A guide to rational eating

February 2023 note: I wrote this in 2018/2019 in an attempt to summarize what I’ve known about rational eating and the obesity epidemic back then. I still agree with the points here, specifically that unchecked sugar intake, big food lobby, poor lifestyle habits including bad sleep and misunderstanding ones dopamine circuitry is the main culprit. The doc is up for serious update / rewrite in better form though.

The main reason I see for people failing to design and maintain a healthy diet is lack of information. Misconceptions are abundant: why we gain or lose weight, what triggers cravings, which diets are safe, which are questionable and which are counterproductive. My main motivation writing this article is to dispel the prevalent misconceptions and bump up your chances of succeeding in leading a sustainable, healthy lifestyle.

Where do the common misconceptions come from? Shouldn’t all the information available in media have by now taught the population what’s good and what’s bad for them? The trouble is for each grain of truth in the media, there’s two tons of commerce trying to sell us on health products, fad diets, kitchen gadgets, cooking courses and gym memberships. Media in general, and social media in particular, are not a good source of dietary information. When it comes to nutrition it is best to seek advice in books, scientific articles, from trusted nutritional experts or strictly independent websites.

Unfortunately for you (and anyone else who has to listen to me), I have a tendency to repeat common-sense / general-knowledge dogmas. Sorry about that, please skip parts that sound obvious to you, I keep them in for completeness.


Unless mentioned otherwise, below applies for people who either don’t exercise or maybe go to the gym twice a week or jog twice a week. Performance athletes need a different diet, pro athletes and people with serious weight issues or health conditions will need radically different diets.

And talk to your doctor before doing anything, of course.

The Caloric Equation

Let’s get right to the physics: any food or drink you swallow has some amount of energy in it (measured in calories). Once it’s in your body it won’t magically disappear, the body has to do something with it. These are the options:

  1. Use up via basic metabolism / keeping the lights on. Examples: maintaining body temperature, heartbeat, breathing, brain activity.
  2. Use up by feeding skeletal muscles during activity. The more vigorous the exercises the higher the caloric demand.
  3. Store excess as fat and glycogen.
  4. Pass whatever was not digested as waste. Not all consumed calories can be digested by human body and there are diseases that hamper digestion of certain foods.

For any given period, the summed energy disposed of by 1. to 4. equals the total consumed calories.

The equation is something to keep in mind as a quantitative model of human metabolism yet it should not be intuitively applied towards weight loss. Not only is the amount of calories one can burn through exercise over long term limited, it is also unwise to try to drastically curb the volume of calories consumed.

As the rest of the article explains, healthy lifestyle and eating habits should instead focus on the nutritional composition of the daily calories, not disturbing the basic metabolic rate and staying active.


Maybe you like to dig around the garden two hours a day, maybe your job is physically demanding like you’re walking and lifting heavy objects all day. Or maybe you are a university squash coach and play squash two to three hours a day. Good for you, you might not need to worry about burning calories. The rest of us generally burn extra calories by exercising more.

What is desirable is a form of exercise that needs relatively little willpower from you and to which you have easy access to. For instance, starting a new sporting activity to help with your calorie balance is tricky in short term because it means the activity is not part of your lifestyle already and you will need to rely on your willpower to kickstart it. Be ready to fail and restart several times before the habit sticks.

Of course, there are people who require no willpower to do daily sports. They either have an existing endorphins addiction (usually built by doing sports throughout teenage years and twenties), or are naturally competitive and addicted to (the idea of) crushing the opposing teams, individuals and sometimes buddies on tennis courts, football pitches, swimming pools and mountain trails. It is desirable to be a part of this zero-willpower-exercise category.

There’s also those who perpetually do sports for social reasons, e.g. most of their friends are part of the given floorball club. This is less reliable way to maintain doing sports long-term as friends leave for other clubs or just give the sport up. It suddenly becomes more difficult to keep at the previous exercise regime.

On top of motivation and availability issues there are sporting injuries. The luckiest athletes are out of the game maybe once a year or so. The most unlucky ones are forced to withdraw from the sport completely due to musculoskeletal issues. The older one gets the higher the chance of the latter. Most active amateur athletes are somewhere in between, their year splits between riding the good times and fighting motivation loss after a period of injury or illness.

Some people have success burning more calories by ditching car and walking to work. Bicycle commuting works too but the commute needs be longer. For instance, 5 km low-effort bike commute of an 80 kg person burns about 150 calories while running the same distance burns about 400 calories.

All in all, you can not rely solely on exercise to get slim, which means the only truly reliable calorie-balancing tool you have at your disposal is controlling what you eat, how much and when.

The above is not to say people shouldn’t exercise: they absolutely should, in a way that is sustainable over years and decades. There are massive secondary benefits from exercising: improved sleep and mood. These are powerful, if not essential, weapons with fighting weight gain. Also, the benefit of doing sports compounds over time. It’s way easier to maintain muscle mass than to build it (in terms of learning curve, willpower, time investment) and the more muscle mass you carry, the higher your basal metabolism.


The bad news: making healthy diet and exercise a habit usually includes some mental suffering which means one has to use his willpower before it sticks. No matter how much willpower an individual has, it will run out eventually if the diet takes too much of it every day.

Thus whatever nutritional plan or exercise regime you devise for yourself make sure it takes it easy on your willpower else one day you will fail and in doing so setup a failure for the next day etc. There are techniques to avoid that:

  1. Start with a single change (“no Starbucks Friday”) and let it click into your lifestyle before continuing with the next one.
  2. Frequently reflect on whether the regime you’ve got isn’t taking too much of your willpower. If it does, ease up to avoid giving up. For instance, replace a strict exercise program for one that suits your schedule better.
  3. Turn the screw a little every now and then (adding more exercise or dropping more unhealthy items). This helps you progress which replenishes your motivation and boosts the willpower.
  4. Do not stack several willpower drains at a time. Periods around major personal events (moving home, new child, new job) are not good times to focus on a new diet.

See Mini Habits for one popular methodology to help building habits with minimal willpower.

Nutrient Types

The topic of nutrition has non-trivial science behind it. Fortunately this document can afford to keep it to the rudimentary, crude minimum. You can always look things up further.

An adult male should target eating 2500 calories a day, adult woman 2000 calories a day. These are rough numbers that change with height, age and other factors. It is also a target to hit, not something to exceed or come short of in order to manipulate one’s weight. For that it’s better to look at the exact source of the calories.

The three major nutrients a human body needs are carbohydrates, fats and proteins. The consensus is that a healthy diet supplies 30% of total calories consumed in protein, 30% in fat and 40% in carbohydrates. One gram of fat has about twice as many calories (nine) as either protein or sugar (four calories each).

Carbohydrates are the most available, basic fuel our bodies burn to perform physical and mental tasks. They categorize depending on their molecular structure into simple (AKA sugars) or complex (polysaccharides). The table (white) sugar is 100% simple sugar (sucrose specifically) of course. But sugars are plentiful in fruit, syrups, candy, sodas, cereals and honey. Higher than low proportions of sugar are undesirable in a diet and polysaccharides should be the bulk of ingested carbs. They come from dark bread, pasta and starchy vegetables like potatoes.

Proteins are essential for regeneration and synthesis of body tissues, especially muscles. Metabolism of proteins has a high thermic effect, meaning the body has to spend about 30% of all calories in the ingested protein to process it (it is only half of that for fats and carbohydrates).

The recommended adult reference intake of protein is your weight * 0.00075. A man of 75 kg should eat 56 grams of protein daily.

Fats can be saturated and unsaturated. Saturated fats are found in animal products (meat, milk, cheese, butter), usually solid at a room temperature and considered unhealthy in high quantities. Unsaturated fats are generally found in plants (nuts, avocados, vegetable oils) and are liquid at normal temperatures. There are many exceptions, palm oil for instance is a saturated fat. Unsaturated fats in moderate quantities are good for you, if not essential.

Fats are what carries much of a taste of a meal. Without a bit of fat in it it’s hard to enjoy eating anything. This is the reason why salads are boring without any dressing but better with plain olive oil or crumbled cheese.

Bloodstream Glucose Levels

One thing I want to explain in detail is how ingested carbohydrates act in the bloodstream.

Before the body can use up any ingested (or stored) carbohydrates for fuel it needs to deliver them to the bloodstream in the form of glucose, a simple sugar. Eating carbs temporarily increases the amount of bloodstream glucose (BG), but since it’s higher than the optimal BG level the body reacts by releasing insulin, a glucose regulator which in healthy individual quickly drives the BG level down.

Plotted in time we would see that blood glucose (BG) level forms peaks during the day which follow times of meals and are themselves closely followed by peaks of insulin levels. After a peak, the glucose level falls off and stays low until the next meal.

There is an optimal, healthy rate at which glucose level should drop after a meal but eating a meal with high proportion of simple sugars adversely disrupts it. Ingesting sugars causes taller spikes of both BG and insulin. There could be enough insulin in some cases for the BG to fall too rapidly and below the levels prior to eating. And because BG is one of the body’s sensors of hunger, the person feels hungry even though he just ate hundreds of calories worth of sugar. Perverted, no?

Exposing the body to frequent glucose spikes will over the course of years make insulin work less effectively. The resulting pathology is known as insulin resistance and means that after a meal the BG will stay high for a long time. Prolonged BG elevation damanges body’s systems (particularly the nerve system), is a precursor for type 2 diabetes and causes body to produce and release even more insulin. The person will also feel more hungry and so more likely to eat sugary meals, etc.

What happens to the glucose that is pushed back by insulin? The body tries to store the energy for times of hunger, using either of two mediums:

  1. Fat, either visceral (around internal organs) or subcutaneous (skin). Neither is desirable.
  2. Glycogen in the liver and skeletal muscles.

While glycogen is an awesome fuel (e.g. for middle-distance runners), the body needs to be trained to both store and use it. More frequently one’s glycogen storage capacity is severely limited and the extra consumed calories end up being stored as fat. Normally this is not a problem either as body fat plays several important roles, a convenient energy store being just one of them, especially if there ever are periods of hunger.

Recently a hypothesis has been popularized with overwhelming supporting evidence by which sugar consumption and insulin resistance causes hormonal imbalance that elevates the fat tissue’s readiness for storing fat even at times when the person does not overconsume. Lowering caloric intake then results in feeling of hunger and accumulation of fat, both at the same time. Moreover, this effect is permanent.

I hope I am making the case against sugars clear: they lead to insulin spikes, which lead to insulin resistance and irreversible changes to fat tissue, which starts accumulating fat even at times food is not abundant.

One does not need to give up carbohydrates entirely but certainly should avoid simple carbs (sucrose, fructose) that are densely packed. These need little work by the metabolism and they are fast-tracked to arrive at the veins all at once to cause metabolic mayhem. (Notice how fruit is fructose-rich yet does not concern us as much because its calories are not as dense.)

On the other hand, the metabolism needs to work hard to obtain glucose molecules from complex carbohydrates, which takes time and energy. The glucose fuel is therefore released gradually and over a wider time window, smoothing out the BG curve into a healthy shape.

The ratio of simple carbs in the given foodstuff is sometimes expressed as Glycemic Index (GI). Indirectly, it is a metric of foods to avoid. The higher it is, the relatively more simple sugars it contains. White bread, ready-made desserts, sweets, beer all have high GI. See Diogenes website for the most comprehensive database of GI in various foods.

Without internet simple rules of thumb for wild-guessing a GI are:

  1. The sweeter the food tastes, the higher the GI.
  2. The more cooked the food or its ingredients are, the higher the GI. Observe that cooked vegetables have higher GI than raw vegetables. This is due to cooking heat breaking down fibre and breaking down complex carbs into simpler carbs. This effect contributes to the sweet taste of a carrot cake.
  3. The more processed the food or its ingredients are, the higher the GI. For instance, white flour bread has higher GI than wholemeal flour bread.


Human hormones and their interactions are complex. Because they affect fat storing, muscle building, sleep and mood, they deserve a mention, albeit brief.


AKA “the T” or “the youth hormone”, this is the favourite hormone of the fitness community as it makes the body react to exercise by building and maintaining muscle tissues. Naturally high T is desirable for many other reasons possibly including:

  • improved cognitive functions,
  • relaxed mood,
  • boosted fat metabolism, and
  • higher libido.

Some people have naturally low T (relative to their gender) and in all people it decreases as they age. Decrease in testosterone levels is a major cause of gaining weight later in life despite no other lifestyle changes. Testosterone replacement therapy (TRT) has a merit when medically indicated (as opposed to “getting more gainz, man”) and something to discuss with a doctor if you find yourself gaining weight suddenly in older age.

There are natural, albeit limited, ways to elevate one’s testosterone:

  • exercise, especially weight lifting,
  • high quality and right quantity night’s sleep,
  • a diet with high amounts of fat, especially plant-based fat, and lowered proportion of carbs (especially sugars),
  • supply of vitamin D (ideally by spending 30 minutes or so a day in the sun with low-factor sunscreen), Zinc (from red meat) and Magnesium (from grains, beans and nuts),
  • frequent sexual activity (according to some studies),
  • engaging in competitive sports (and winning).


Depending who you ask, dopamine is the hormone that motivates you to do something that you find desirable or that makes you feel good while and after you’ve done that. It’s the feel-good hormone. Normally, dopamine rewards come from activities we find pleasurable: eating food, drinking coffee, smoking, consuming alcohol, having sex (including masturbation) and video games. As management gurus like to emphasize, finishing a task at work also rewards you with dopamine. Cocaine gives a massive dopamine hit to first-time users but dopamine plays a role in all chemical drugs. We all are programmed to like our dopamine and by and large operate in ways to get it often every day which is why all of the activities and substances listed above are all mildly to severely addictive.

For people who are not addicted to drugs (including nicotine) food is what answers a portion of our daily dopamine cravings. Nothing wrong with that, but it is something people who have little else than food going on in their lives should watch out for.

As physical activity produces dopamine, there’s yet another reason to regularly exercise.


The lifestyle-minded person’s private enemy #1, cortisol is the stress hormone. When things are going awry and everyone pisses you off and you’re under pressure and feel like yelling or curling into a ball, that’s cortisol doing that to you. And while it makes you feel that way it pumps up your blood pressure and slowly starts disintegrating your brain and body. Weight regulation-wise it impacts you many times over:

  1. When we’re stressed we demand more dopamine and frequently turn to high-calorie foods and drinks to satisfy the need.
  2. In males, cortisol causes the body to store more fat around waist.
  3. Cortisol drives down bloodstream testosterone, making the two hormones kind of sitting on the opposite side of a sea-saw. High cortisol = low T. There’s a theory explaining this: both cortisol and T are synthesized from cholesterol. A stressed body consumes more cholesterol to produce cortisol so less cholesterol is left for testosterone.
  4. Cortisol aids build up of insulin resistance.
  5. Cortisol interferes with proper sleeping patterns, resulting in more fatigue and so even more cortisol the next day.

These all might have causation links but this is not a scientific treaty of cortisol’s mechanism of action, this is to make you appreciate cortisol needs to be avoided at all cost. The commonly cited ways to do that:

  • actively avoiding situations which reliably make you stressed,
  • making sure to turn off from work for several hours every day,
  • getting good night’s sleep,
  • exercising,
  • practicing relaxation and meditation techniques,
  • limiting sugar intake.


Adults need seven to nine hours of sleep every 24 hours. Most adults born after 1980 think they need less, they are wrong. Lack of sleep has several negative physical and cognitive effects. For our purposes however the worst of them is increased bloodstream cortisol signaling body to store more energy into the adipose tissue (i.e. fat). And it works in the opposite direction too whereby a pumped-up, cortisol-loaded brain finds it harder to fall asleep.

High cortisol is not the only bad hormonal effect of poor sleep. Decreased human growth hormone (HGH) which is released during sleep is a problem too. HGH helps restore the body’s tissues and not getting enough of it increases risks of injuries and developing aches. Failing to get enough sleep after a gym day limits the total nightly HGH in the body which in turn limits the upsides of exercising like increased fat metabolism, muscle recovery and muscle growth.

In men, habitually sleeping 5 hours a day lowers testosterone to the level of someone ten years older who sleeps normally. Conversely, some Spanish-speaking countries call a lazy person “huevón” which literally means “one with big testicles.”

There are also anecdotal observations that a poorly rested brain has weakened willpower and craves more sugars. See if you can personally detect this causality.

How to get good sleep

Aim to sleep seven to nine hours every night so you are not tempted to compensate and binge-sleep on the weekend.

Screens of electronic devices (including phones, laptops and TVs) emit blue light which is known to offset sleepiness. Many people who have to work late find blue-light blocking apps helpful. The block should be on at least two hours before going to bed. Most devices (including Windows 10, iOS 12 and modern Linux desktops) have some sort of blue-light block out of the box, it just needs to be manually configured. The original e-ink readers did not have any backlight source so you could use a yellow-light table lamp to read. The modern e-book readers typically have LED backlight which contains blue light in its spectrum and so are not ideal for bedtime reading without using the blue-light blocking app. The blue light phenomenon is something to consider when shopping for bedroom lights.

Alcohol, among other negative effects, also disrupts sleep as it reduces the amount of REM sleep and causes dehydration. Obviously, one should be mindful about his caffeine intake during the pm hours.

Taking measurements

Measuring progress

Establishing a quick feedback loop about your progress is paramount: it puts you on top of your progress (or regress) in achieving your goal. The system I recommend:

  1. Two to four times a week, at the same time of the day, write down your weight and quantity of subcutaneous fat and muscle mass if you have a way of measuring them.
  2. Once every other week, or monthly, see how you did compared to the previous period.
  3. Draw conclusions and tweak your diet and exercise regimes slightly and within the bounds of your willpower.

There are several approaches to measuring visceral and subcutaneous fat. What your digital scale has is not precise but certainly better than nothing. A good method to measure subcutaneous fat at home is using calipers, although you’ll have to learn how to do that. There are modern medical devices that measure both types of fat very precisely but one needs to visit a hospital and probably pay for it. Still worth doing once a year or so, if you can afford it.

In the long run it does not matter at which time of day you take your measurements as long as it’s the same time.

When analysing the progress note that bodily metrics are notoriously noisy: after eating moderately and doing sports one day you will inexplicably find your weight up by 0.5 kg the next day. This is usually normal and caused by water retention and it is why I would not recommend evaluating the metrics more often than every other week: there’s just too many variables impacting the weight. What’s relevant is the overall trend over long periods. This data noisiness is yet another factor that makes succeeding in regulating body weight hard, especially if you are not aware of it.

The metrics should move in the desired direction very slowly. What should alarm you is not just trend opposite to the desired one. A change that is in the right direction but too fast (like losing 5 kg in a month) is a cause for concern too as it is likely unsustainable and will reverse with vengeance.

Measuring inputs

This is advanced, but I recommend not stopping at measuring your progress like current weight or muscle mass but also measuring the inputs and keeping track of how much you actually eat. For example, my dinner is usually around 600 calories. When preparing pasta dish for myself I know I want to cook precisely 130 grams of pasta. This gives me about 400 calories, leaving plenty of margin to add pesto, veggies or ragu. Knowing the dried pasta weight of my typical pasta dinner and actually bothering to take out the scales assures that I don’t end up hungry or overeating.

At the same time it also gives me a gauge I can manipulate with. If I decide to shed 3 Kg of body weight for a cycling event I start cooking only 115 grams or perhaps just 110 grams. The point is that the long-term baseline of 130 g has been established and now I can tweak the knobs, avoiding drastic swings in the total daily calories.


Honourable mention of the measuring section: wearables. Their recent commodification can be a boon for healthy living, particularly for those analytically oriented. Besides giving feedback about one’s daily activity (something to work in when analysing recent progress weekly or fortnightly) they are especially useful for monitoring sleep quality. Because good sleep is crucial for maintaining healthy weight a fitness tracker is a reasonable investment on the quest to systematically improve it. Even inexpensive device will reliably flag the sleep after a pub night or after a stressful day as low-quality. One can conclude that it does measure something and thus can be used to map out patterns of activities that lead to low-quality sleep. Seeing the data should not stop you from socializing but it might highlight one hidden cost of drinking alcohol.

Sourcing food

If you forget about the occasional date-night restaurant dinner, work lunch, on-the-go snack when traveling and eating at your mum’s on Sunday, there’s three to six meals every day that you have complete control over. This section explains how to avoid making the wrong choices.

The best and costliest approach is a personal chef whom one explains his dietary needs and goals and the chef follows them like Holy Writ sprinkling deliciousness all over. I can’t say I have a personal experience with this so I won’t elaborate further. It must be great!

You can eat out all the time. Anecdotally, I’ve known people who have lived that way and none of them have looked fit. The cheap take-away options are inevitably of a low nutritional value. Going into a respectable restaurant for three meals a day is time-consuming and costly.

What most mortals realistically resort to for bulk of their meals is sourcing food from a supermarket.


Which brings us to shopping. Supermarkets, not kitchens, are where most weight-adjusting battles are lost or won. An individual who does not have enough willpower in the supermarket and ends up buying junk food will certainly not have the willpower to keep the junk food in cupboard forever or throw it away in the end. I want to bore you by emphasizing this more: the easiest way to stop eating junk food is by not putting it in the basket and not checking it out of the store.

Entering a supermarket having a shopping list ready (backed by a list of meals to cook that week) is a good idea. That way you can both eat healthy and cut down on food waste. Without a shopping list the tendency is to shop impulsively, resulting in a fridge full of food you either don’t know how to cook, don’t want to eat or junk food.

I recommend having groceries delivered from an online store. For one, it saves time. Mainly though it forces you to literally make a shopping list, providing more opportunities to keep junk food out. Shopping for groceries online is like shopping on eBay: expert execution requires you do it sober and allow yourself enough time for it. You still end up ahead with the time saved driving, browsing isles, waiting for a checkout and hauling the stuff back home.

You can save a lot of money by shopping on farmers’ markets. Compared to supermarkets the vendors save on marketing and retail space and they certainly don’t want to drive home with half-full vans. Their prices reflect that. Plus, because all they often sell is fruit and veg, it’s straightforward to stick to buying only fruit and veg.

To a large degree with supermarket food, you get what you pay for. For instance, cheap fruit is sometimes either not ripe or about to spoil soon, making you less likely to eat the fruit after you bring it home, making you more likely to eat crisps for a snack. Price of course is by no means an absolute quality measure of groceries: in many countries forking over extra for “organic” or “bio” food does not yield less artificial or tastier food. Familiarize yourself with your country’s legislation on this.

A couple of tips to save money on food and still eat healthy:

  • Avoid food waste.
  • Follow your shopping list. Especially resist the temptation to buy discounted junk food. Not on the original shopping list? Not in the basket.
  • Tweak your weekly menu according to the fruit and veg seasonality, aim for the locally produced stuff
  • Surf between the online grocery shops. Nowadays each of these tracks the shit out of your purchases (what you buy, how often you make orders, when you get them delivered) and they can precisely calculate the moment you started shopping with them exclusively. No more freebies or special discounts for you if you’re already loyal.
  • Consider cutting down on your meat to about 70 g/day or less.
  • Learn how to prepare legumes (like beans and lentils). It’s a cheap source of non-animal protein. And there’s nothing to it, you just boil them.
  • Not all junk food is cheap so cut it out.

Junk food

Junk food is anything that meets the following two criteria:

  1. Provides nothing besides one specific nutritional item (calories in the form of simple sugars and saturated fat, typically).
  2. Tricks your brain into Lovin’ It, no matter how not hungry you are.


  • sodas
  • energy drinks
  • candies
  • ice-cream
  • sweet caffeinated beverages (but plain black coffee is not junk food)
  • hot dogs, burgers etc. sold at fast foods or corner shops.
  • crisps
  • most ready meals in the supermarket
  • most pastry
  • most cereals, check labels for sugar content
  • processed fruit juices

If a product is advertised in media, it’s probably junk food. There are no carrot ads during Formula 1 commercial breaks.

From the list above, sodas are by far the worst. The maximum recommended sugar intake for a man is 37.5 g per day. One can of coke already takes you over the budget with its 39 g of sugar.

On the topic of coffee house beverages. There have been Starbucks drinks with whopping 99 g of sugar per serving and most small-size lattes have around 20 g. Is it still coffee or already soda? My recommendation is researching how much sugar there is in your favourite cup and coaching your barista to add no syrups, sugars or powders into your cup. Even better option is making your own coffee or getting a colleague or a spouse make it for you.

Sugar addiction

This could be said in connection to junk food but is actually the core issue for most people with weight troubles.

Sugars are addictive. We discussed how our brains dopaminise us for eating sugary things (“Easy fuel!” thinks the mammalian brain). Sugary food and drinks are also very available. For instance, I bet it’s closer than 7 minutes walking from your work desk to the nearest coffee chain outlet. Frequently, sugar-rich food and drinks appear cheap per unit, that is until you work in the cost of your health and that your purchase will be repetitive once you’re hooked. It is completely legal to sell sugar to anyone, even kids. And there’s also commercials that make drinking sodas look very cool. The addiction recipe is complete.

Sugars are just a nutrient type, granted, but the form in which they occur in nature has nothing to do with refined sugars found in candy and other junk food. A piece of fruit will also contain sugars, but much less densely, meaning they occupy more space in your stomach and make you feel full sooner, not least because they contain a lot of fibre which also slows down the sugar digestion. To illustrate: two oranges have about the same amount of sugar as 50 g of a lemon cake. Eating two oranges is some work, you have to peel them, they’re a bit sour, it takes time to chew them and you’ll be bored and somewhat fed by the end of it. Eating a small piece of cake is a piece of cake and you’ll probably want more afterwards.

While it is entirely possible to have a perfectly healthy diet for someone who is vegan, vegetarian or has severe food allergies, I contest it is not possible to have a healthy diet on top of a sugar addiction. It’s simple to see: if one eats too much carbs, either the total calorie budget increases or one ends up eating less fats and proteins.

Sugar addiction is the main contributor to obesity epidemic in the western world. Sugar addicts need a Starbucks before getting to work, hope for a birthday cake in the office, tend to order dessert after lunch, get some pastry with 5 pm tea, eat pancakes for dinner and then have ice cream to watch Netflix with.

The ultimate advice to beat sugar addiction is not to get there: be mindful of things that taste too good to be true and employ self-regulation while it’s relatively easy. Don’t buy candy even if you have the spare change for it, refuse when offered.

I’m not aware of a bullet-proof sugar-rehab programme. Much like with other addictions, I don’t think there’s such a thing. There are only some guidelines.

Start watching it. Learn how many grams of sugar there is in everything you tend to consume regularly. What was the most sugary item today and yesterday?

Seek snacking alternatives. Because there is nothing more convenient that tearing open a Mars bar, we often default to confections for quick snacks. Instead, research and create a list of healthy snack alternatives. Those can be fruit, veggies, nuts, hummus, beef jerky, unsweetened milk products like cheese, quark, cottage cheese, Greek yogurt). To gamify this snacking a little, be on the lookout for new types of healthy food you haven’t tried and aim to include one every week until the supermarkets can’t offer anything new to you.

Be aware of “fake healthy”. A nasty scam which food companies have been increasingly pulling off during the last decade is “0% fat” dairy products, e.g. yogurt. A real yogurt has about 10% fat, it contributes to what makes it taste great and what makes it nutritionaly valuable. The food companies take the fat away to produce another, higher margin food (typically cheese) and now they are stuck with a fat-less substance they want to sell to customers, repeatedly. What do they do? Add a thickening agent and about 15 g of sugar to every 100 g of the substance and call it “0% fat yogurt”. This sugary food will in the end make a person more fat than a regular plain yogurt. Moral of the story: read labels, particularly on items that taste too good to be true.

Give yourself time to wind down from sugars gradually. Sodas must go first. Then no desserts with meals unless someone else at the table suggests to get them. Then reduce number of candies in your weekly supermarket basket to five, three and finally a single item. Then no-Starbucks Monday. Then also no-Starbucks Friday. Then no desserts ever. You get the idea.

Remove sugars from your environment. Ask your closest family, friends and colleagues to help you en route, e.g. by not bringing sweets or pastry into your house or office.

Some dieting gurus recommend weekly “cheat days” when you can (ch)eat what you want. I experimented with this and had a Saturday cheat day for a while. It turned out that I got the worst weekly craving for sugars on Sunday, the day after the cheat day, not the day before. That suggests that cheat day actually does not alleviate the cravings, quite the opposite, it reawakens a dwindling sugar addiction. YMMV.

Regularly reflect on your daily sugar consumption. Is there a particular situation in your daily routine that makes you crave sugars? How difficult is it for you to remove or dampen down the trigger?

This will take time on both macro and micro levels. On the macro level, you’re mainly fighting your lifelong ignorance about sugar and food in general and climbing a learning curve. On the micro scale, preparing celery sticks with blue cheese dip for dessert is more effort than taking a Cadbury trifle out of fridge. Remember: you’re investing the time in yourself.


One gram of alcohol amounts to 7 calories. Those can not be used as energy by the cells, but can be transformed into fat by liver. Moreover, during times of intoxication, the body scrambles to get rid of the alcohol and pauses metabolic processes that get energy from stored fat. Alcohol is also appetizing. Finally, alcoholic drinks often have some carbohydrates inherently present (beer) or mixed in (Jack and Coke, yeah!). It’s those carbs and not the calories of the alcohol itself that are most detrimental to a slimming diet.

Alcohol disrupts sleep. It also dehydrates the body at night and brings on hangovers which do not really boost the willpower or energy to cook healthy and exercise.

In the UK the NHS has guidelines about how much alcohol is OK to drink weekly. I would be wary following those, the number is likely inflated. For one reason, in countries where alcohol is legal, the alcohol companies have a strong lobby. If a strong proof existed that the healthiest amount of alcohol to drink was zero alcohol (the revered red wine included), would the government get away with encouraging it? Second, the guideline number likely has the risk of addiction as a primary concern, healthy diet is secondary.

My advice would be kicking any alcohol for life, but that would literally be preaching water while drinking wine. Instead keep your eyes open, keep tabs on how much you drink and don’t give in to the peer pressure and advertising.


Does eating fat make me fat?

It likely does not and if it does then indirectly.

Unlike for simple carbs, the body has to do a lot of metabolic lifting to process fats and either use them up for energy or store them again as fats. The process takes some time and the products of the initial fat breakdown (fatty acids and glycerol) do not spike bloodstream insulin. So you end up feeling fed for longer than with simple carbs.

Are there downsides to eating fat-based diets? Yes. Some studies link saturated fat (majority of animal fat) consumption and cardiovascular diseases. There is also strong evidence for saturated fat boosting one’s appetite.

tldr; target 30% of all daily calories from fat, preferably as vegetable fats (nuts, avocados, olive oil, etc.) and fatty fish (e.g. salmon).

Does eating sugars make me fat?

It does, the exact mechanism how is described above.

Sugars are the dominant reason why the fat people in western world are fat. Our bodies are not specifically designed to be gaining fat from sugars, it is a synergistic result from a combination of factors:

  • Ancient humans never ate calories as densely packed as Salted Caramel Haagen-Dazs so there’s no evolutionary reason why the current day human bodies should be able to cope with it.
  • Our brains stupidly reward us with pleasurable feelings when consuming simple sugars.
  • The 21st century agriculture can manufacture highly concentrated sugars really cheap (think refined sugar, high-fructose syrup, corn syrup), making sugary junk food relatively cheap (not counting the hidden costs of your health) and abundant.

Also see junk food discussions above.

I have been overweight my whole life. Can I still lose weight?

Perhaps to a degree and if you can do it through other means than calorie-restriction diets.

An extreme example of “too late” is the American version of The Biggest Loser reality TV show. In a study by Kevin Hall over 90% of successful contestants regained weight in the six years after the end of the competition. And it was not because they stopped caring. The study showed that with the initial weight loss their resting metabolisms slowed down drastically, much below the rate normal for an average person (in one case below 2000 calories per day for a male). This exposed the contestants to excruciating hunger, forcing them to eat more and gaining again. To quote NY Times reporting the same study:

It was as if their bodies were intensifying their effort to pull the contestants back to their original weight.

The results of Hall’s study confirm what dietologists have known intuitively for decades: the more diets someone tried, the harder it is for them to maintain low weight.

Second, basal metabolic rate is thought to decrease as we age by about 1.5% every decade. If it was hard for you to lose weight ten years ago, now it’s harder and will be even harder ten years from now.

Third, severe obesity makes it hard to start and sustain regular exercise: the joints and tendons are overloaded and injuries are bound to be frequent.

The moral of the story: the odds of losing weight gained over decades are stacked against the obese. Remember this if you are healthy, in your twenties and have a stressful life where you sit on an office chair 8-10 hours a day, eat Chinese take-outs for lunch, own a loyalty card in the Caffè Nero next door and spend weekends partying and playing Xbox.

If you are obese already then do make changes to your diet and lifestyle ASAP. Be super-gradual and calculated about it. Be smart and patient.

Do women risk getting a “ripped” look if they lift weights?

Exercising up to five times a week, without use of anabolic steroids: resolutely no.

It takes a lot of lifting in the gym even to the most manly man to look ripped. A 50 minute workout in the gym two times a week has no risk of causing bulking up yet the benefits for overall well-being are tremendous.

Besides, an old Irish proverb says there’s only two types of women:

  1. Whose thighs already benefit from deep barbell squats.
  2. Whose thighs would benefit immensely from deep barbell squats.

Granted, gym is not for everyone. But it would be a shame to dismiss it by thinking it will inevitably make you look like a Hulk.

Do meat-free diets cause muscle loss?

Yes, if you are not mindful about including enough protein in your diet. Meat is a good protein source but so is cheese, quark, eggs, tofu, fish, beans (also in bean spreads like hummus), nuts and mushrooms.

What is up with zero-calorie artificial sweeteners (ASs)?

The situation is unclear. There is apparently no consensus whether ASs are OK or harmful. They probably increase one’s appetite which causes intake of actual calories. Some studies even show that they negatively impact metabolism through interference with gut bacteria, even making lab mice gain weight.

The commonly noticed phenomenon that ASs do not cause weight loss has even been observed by a US president.

Drinking zero-calorie sodas is less harmful for one then drinking the sugar-laden versions. Nonetheless I’d still advise to avoid them.

Calorie-restriction diets

Calorie-restriction diets are a family of diets where the individual limits his daily caloric intake compared to his long-term baseline or even to the normal level given his sex, height and age. Some research reports beneficial outcomes of the regime like offsetting effects of aging, improved alertness, retaining more lean muscle mass over time, reduced inflammation.

For the unsophisticated mildly overweight just “eating less” is the default, intuitive, first approach to weight loss. For this purpose it usually fails because in reaction to sudden cut in caloric intake the body (perhaps permanently) throttles basal metabolism. Ultimately one feels more tired and becomes less active. The dieter will experience great weight loss initially but he will gradually re-gain the kilos especially if he is not able to maintain the diet essentially forever. Simply put, calorie-restriction does not work for long-term weight loss.

There is a place for calorie restriction for truly obese who overeat. It might not help them reduce weight but can prevent gaining further and hopefully prevent or offset development of related diseases like diabetes. The rest is probably better served looking elsewhere.

Vegetarian and vegan

Vegetarian is someone who doesn’t eat meat and there’s no consensus if fish are considered meat for this purpose. Vegan is someone who eats strictly plant-based food. A vegan won’t eat fish nor any other animal products like eggs or milk. There is no consensus among vegans whether insects count as animals, so honey may or may not be admissible.

Scientific evidence has existed for some time now that animal fats do increase risk of cancers and cardiovascular diseases and boast your appetite. There are also environmental considerations: farming cattle and seafood produces substantial volume of greenhouse gasses (however, it’s up to much debate even from the climato-vegetarian community how much).

How much meat is OK to consume for a person? British NHS says no more than 70 grams a day which could be a good initial target. Notice how little it actually is: despite being enhanced with water a raw supermarket chicken breast of 150 g will still be about 100 g cooked. That was your daily budget and then some. What about your breakfast slice of ham and lunchtime burrito? And the 70 g/day marking is likely still too high, the NHS is financed by the government who doesn’t want to alienate the farmers.

My recommendation to the general population is to follow the NHS advice ASAP and start experimenting with limiting meat consumption further. Try being vegetarian one or two days a week flexitarian-style and reflect how you feel compared to the rest of the week. Importantly, follow the diet for a prolonged period and assess its measurable effects.

Purely plant-based diets are historically proven. There are places (AKA Blue Zones) where generations have been eating this way for centuries and statistically enjoy the longest, healthiest lives.

Going vegan is an order of magnitude more difficult than vegetarian, however. The main pitfall is sourcing protein when many good options including fish, eggs and cheese are off limits. Second, all vegetables have carbohydrates and so tip the caloric composition towards high-carb. To counter this, one should consume relatively low amount of starchy vegetables (potatoes, beets, corn, etc.) and high-carb fruits (bananas) and consume major part of vegetables uncooked. Third, no vegetable or grain contains all of the essential amino acids the body needs. In effect a rational vegan must know which amino acids are represented in each food stuff and design his menu accounting for that. Finally, plant-based diets supply no vitamin B12. B12 deficiency causes all sorts of freaky physical and neurological disorders. If you decide to go vegan make a plan on how you supplement B12 (yeast is one good source).

Before turning vegan try to compile a sample weekly vegan menu for yourself. Depending on the vegan options where you live, you might find it surprisingly difficult to arrive at the 30% proportion of consumed calories in protein. In other places (including UK) it is relatively easy but you still have to go out of your way and sometimes pay up.

Absolutely prepare to exert higher effort while researching, shopping and cooking. Granted, you will benefit from leaving out animal fats entirely, but make sure to calculate the real and hidden costs. Insufficient protein intake has worse impact on children, youngsters and athletes so be mindful if imposing the diet on one of those groups. I would be cautious adopting a strictly plant-based diet cold-turkey. There are too many things an inexperienced vegan has to watch out for and easily does himself more harm than good.

Gluten-free and lactose-free

These diets were all the rage in early 2000s: people, no doubt influenced by media, assumed their particular ailments could be explained by food allergies, so they experimented.

In fact, lactose intolerance or gluten sensitivity causes only few and quite specific issues and before jumping to the conclusion your doctor should test you first.

Otherwise it is probably better idea to avoid such diets if you have been used to eating e.g. what-flour bread since childhood and obviously do not have a medical condition imposing it. There is no evidence gluten or lactose are harmful for the generic population yet at the same time one can develop lactose intolerance by having strict lactose-free diet for a long enough time.

Ketogenic diet

Or zero-carbs diet. In this regime you target to eat less than 20 g of carbohydrates a day (80 calories, i.e. less than a tenth of the recommended daily carbs for a male). Dieting this way forces your cells to start processing body fat, breaking it down into ketones. Those can then be measured in your urine (using special strips from the local pharmacy) giving you a nice feedback loop you’re on the right path.

In practice, those who followed the diet did report continual weight loss but also some of the strongest, constant urges of their lifetime to give up and have a bowl of noodles. Some even perceived temporary decrease in cognitive functions and downswings in mood bordering fatigue and depression.

Ketogenic diet certainly does not meet the criteria of something you can adapt for a lifetime. In this sense failure to adhere to it is inevitable. A rebound in weight naturally follows. Long-term safety of ketogenic diet is something yet to be proven. Avoid.

Intermittent Fasting

AKA “IF” and gaining popularity from 2013 onwards, this diet imposes that you eat the recommended daily caloric volume and composition within a shortened period of time. Many variations exist but typically you eat in the eight hours between 12 pm and 8 pm and consume strictly no calories the remaining 16 hours.

The hypothesis behind this diet is sound: evolutionarily, humans were not used to have food available all the time but once the food became available they ate a lot of it before another period of fasting. Such rhythm teaches the body to optimally store and deplete the right amount of glycogen and fat without causing too many glucose spikes, preventing or even reversing insulin resistance.

Lab studies on rats are very promising and some early studies on humans concur the diet is safe and at least as effective as plain calorie-restrictive diet.

The downside? Some people report a hard time initially starting this diet, from food cravings to dizziness. I personally experience funky mental states by the end of a 20-hour fast period: unnaturally lucid with a heightened sense of smell.

Of all the mentioned diets, IF is the only one I’d recommend cautiously trying out, initially in the 12:12 mode, where all meals are consumed in a 12 hour period every day.

Social circle

It’s said that a person is the average of the six people he spends the most time with. Studies have shown that the same applies for body types. Try to approach this factoid constructively or risk being alone. Personally I have a system to help me and my close ones eat healthy:

  1. Within my social circle I never miss an opportunity to engage in a constructive discussion about healthy eating. Everyone still has got a lot to learn.
  2. When shopping for my family I forget to buy an ice-cream or a marmalade which are on the shopping list.
  3. Unless it’s some sort of a celebration, I don’t ask for the dessert menu in a restaurant after a meal. If other people ask, be it, might try a chocolate tart with strawberries. I just make sure it’s not me who brings up the dessert question.
  4. One day a week I strictly avoid processed sugar, to the point I refuse a slice of birthday cake. If people ask, I explain it’s a rule and what the benefits are. That can not fail to make the questioner be more mindful about their own refined sugar intake.
  5. I rarely bring cake, pastry or sweets into my work to share. In some companies the managers sometimes do this during busy periods to keep butts in seats longer hours. Let’s not be like them. Bring fruit if you must.

A system like this is not simply to coerce your family, friends, colleagues into the desired behaviour (of not buying or offering junk food to you). The point is in the other direction: to lead by example, to help the people you hang out with lead a healthy lifestyle and make it harder for them to obtain and justify eating junk.

Gradual change

It is my hope that the article provides concrete actionable advice about improving your diet although I must warn against implementing any changes too fast. Most lifestyle changes are the kind that the brain hates. Sugar reduction, going to bed earlier, exercising more and harder, fasting. Your brain will scream at you to stop and set you up to fail. Contrary to how the entrepreneurial Zeitgeist has it, when it comes to dieting failing is worse than not trying.

Drastic changes in caloric intake lead to swings in the weight, typically by shedding a lot in the first weeks. But the body will be alarmed by the sudden calorie restriction and will gradually throttle the basal metabolism. The hunger will stay and the fat too.

Instead, the change in the actual body weight should happen under the radar of whatever in the brain thinks what the optimal body weight should be. The point is simple but important: apply slight and steady force towards lifestyle changes and avoid anything drastic. Focus on one aspect at a time (sugars reduction, animal fats replacement by plant-based food, better sleep, etc.) and then going slowly within them (5 pieces of candy a week, then 3, then 1).

Tim Ferris describes a trick to reliably reduce your weight by exactly following the gradual method: set a long-enough timeline (years) and graph a curve of shedding weight in the time with a band around it, both above and below the target. Every week see how you’re doing compared to the graph and adjust accordingly, more forcefully if you are sliding out of the band on either side. Foolproof.


Build a nutrition system rather than a diet. The system must be sustainable and you should be able to imagine following it for the rest of your life, with frequent adjustments and without expending too much willpower every day. Bring in any change into your system gradually and appreciate the risk of a permanently slowed-down metabolism after failing a calorie-restrictive diet.

Take it as a hard fact that it’s sugars just as much as animal fats causing the obesity epidemic. As sharply as your sugar addiction allows, drive your sugar consumption to below 37 grams a day and ultimately to zero. Check your meat consumption is within 70 g/day and prospect to reduce it further. But at any rate stop drinking soft drinks for good this instant.

Learn to spot junk food by habitually reading the labels / small prints on packages and assessing (dare I say counting) calories and nutrient types. A man needs 2500 kcal a day, woman 2000 kcal. If a flavoured yogurt has 5 g of protein and 14 g of sugar per 100 g, an average man would have to eat 1.1 kg of it a day to cover his protein needs. It would however cause him to exceed the maximal recommended daily intake of sugar four times. Such yogurt is junk food.

Get used to the idea that good, healthy food is not fast and sometimes not cheap and convince yourself it is still well worth the investment, no questions asked.

Take weight measurements regularly, evaluate them and keep adjusting your regime.

If you are not rich enough to have a personal chef, learn to prepare your own food, even cook. Convince your housemates, partners or kids to cook too so each of you needs to cook once or twice a week at most. Be careful about putting your whole love into cooking which tends to produce delicious yet unhealthy meals.

Find healthy sources for dopamine hits. Exercise, sex, healthy food and coffee are great ones.

Keep learning about metabolism and food. There are plenty of unanswered questions in the dietary science but researchers make progress all the time. Be open to learn from dieting experience of people even if you don’t intend to copy them. They can provide early data points into the new fads and they might teach you about new cooking techniques and ingredients you didn’t know.

Distrust big food with zeal.

If you are young then get on the healthy path while your metabolism is still reasonable. It is more difficult once your metabolism slows down with age, or when you have diabetes or once your day-to-day becomes so draining you have precisely zero willpower left for adjusting eating habits (long hours in the office, long commutes, little kids to look after).

Control your stress levels and your mood, be mindful of your momentarily cortisol. Take a day off work here and there if needed and find ways to properly relax. Reflect frequently if the lifestyle you’re leading will keep you alive and kicking until your seventies, eighties and nineties.


Below I give a crude list of references I remember vividly reading or watching. It’s pitifully incomplete.

As an athlete in teenage years I followed dietary advice of Petr Fořt (Czech only).

I further started to question the mainstream approaches towards food after reading 4 Hour Body by Tim Ferris.

Chris Hoy’s How to Ride a Bike summarizes the latest conventional wisdom of sports nutrition well.

Scott Adams’s How to Fail at Almost Everything meandering bio/self-help book offers surprisingly relevant, actionable advice on eating low-carb, for-happiness.

The only cookbook I’ve read cover to cover is The Food Lab. Consider it an endorsement as much as a sign of my ignorance.

Hana Kahleova et al. is a group of researches studying intermittent fasting and plant-based diets. There’s a great interview with Dr. Kahleova for the YouTube-fond.

There is much support now for the hypothesis that sugars, and not fats, are to blame for obesity epidemic. Gary Taubes’s article is a good summary of why the researches were getting this crucial aspect wrong.

Some great pop-sci documentaries about food are Forks Over Knives, Super Size Me and Food, Inc.. Fed Up does a great job of explaining the relationship between sugars, obesity and meddling of corporations into our diets. It is on YouTube.

Jacques Peretti’s The Men Who Made Us Fat and The Men Who Made Us Thin drives home many points about fast foods, sugar’s role in obesity epidemic, fad diets and commerce surrounding food and exercise. Highly recommended.

From the well-known websites, NHS has the least commercial, down-to-the-ground advice. Healthline comes up in specific Google searches frequently and I don’t have a reason yet to distrust them.

I like to talk food, dieting and exercise with my friends, some of whom are competitive national-level athletes, others devotees to particular dieting principles. Thanks guys for all those discussions, you enlighten me.

Thanks to #finisher Petr for corrections.