On any product packaging today we see the word “calorie content— – and the numbers opposite it. It would be better not to see. Because to find out that a tiny (as it seemed) eclair just eaten cost you 700-plus calories is really painful. Terrible thoughts immediately come to mind that the abstract figure on the package will become a very real figure on the scales by the evening, and all the pleasure from the beloved cake evaporates instantly.
But what does this terrible word “calories” really mean? How in reality does the caloric content of foods affect our weight and well-being? Exactly how many calories do I need to eat per day to maintain or lose weight? And why did the low-calorie diet, which turned the neighbor into a slimmer, in my particular case did not work?
What are calories?
In a school textbook on physics, you can easily find a definition that a calorie is the amount of thermal energy that allows you to heat one gram of water by one degree Celsius at standard atmospheric pressure. The name of this unit of measurement came from the Latin calor — “heat”.
But the energy value of food is usually measured in larger units – kilocalories, in 1 kcal — 1000 calories, and in this case we are talking about a kilogram of water.
That is, calories are units of energy contained in food, which our body can either use immediately or reserve.
How is the caloric content of food measured?
In fact, it is quite difficult to understand the relationship between an abstract kilogram of water and a real eclair, which contains, say, 790 kcal. And it is also not easy to explain on the knee how caloric content is considered. Today, products are not heated, but burned in a special chamber, measuring the amount of energy they emit using a calorimeter device. But even more often they are chemically decomposed into proteins, fats and carbohydrates, their specific gravity and total caloric content are considered. Moreover, the calorie values for different food groups are well known to us, back in the 70s of the XIX century, they were experimentally obtained by the American scientist Wilbur Atwater, who is considered the father of dietetics: the calorie content of carbohydrates is 4 kcal / g, proteins – 4 kcal / g, fats – 9 kcal / g.
Interestingly, the concept of calorie content became known to the general population only in the 90s of our century. Calorie counting has become part of the idea of the American government in the fight against the problems of excess weight, which is particularly acute in the United States: in 1990, manufacturers were legally required to write the number of calories on the packaging of any product. This practice took root in the USA, and then all over the world.
How many calories does a person need to live?
The answer depends on the conditions of the problem.
There is a concept of basal metabolism – this is the minimum energy expenditure required by the body to maintain vital functions: breathing, digestion, etc. Roughly speaking, this is the energy consumption of the average person who is awake (energy consumption decreases in a dream), but does nothing, but lies on the couch and does not move either hand or foot. Moreover, in scientific language, he is in a state of thermal neutrality: that is, he is neither hot nor cold. The value of basal metabolism for adult women with normal weight is about 1330 kcal, for adult men with normal weight – about 1680 kcal. That is, to maintain basic vital activity, it is enough for us to eat, in the roughest approximation, two eclairs a day.
It is clear that any movement will require additional costs from you. In addition, each person’s real need for calories is strictly individual and depends on gender, age, body weight, lifestyle, proportions of muscle and adipose tissue and other factors. There are a lot of calorie counting systems in which basal metabolism is multiplied by individual coefficients reflecting these indicators, but this is a rather difficult task, which is better to consult a specialist.
Another indicator, the “gold standard” of the daily measure of calorie intake, which is found in the medical literature— is an indicator for a person of an average level of activity. In women it is 1600-1800 kcal, in men – 2000-2500 kcal. But this is also such an “average temperature in the hospital”, which was measured more for statistics than as an individual indicator for real people. Although, in order to keep within the limits and not overeat, these figures can be kept in mind.
How much do I need (and do I need) to reduce my calorie intake in order to lose weight?
There is such a famous “3500 kcal rule”, which is probably known to everyone who has ever tried to lose weight. It sounds like this: to reduce body weight by 500 g per week, a deficit of the energy value of the daily diet by 500 kcal is necessary. If we multiply 500 kcal for 7 days, we get exactly those 3500 kcal per week, the subtraction of which from our diet should automatically mean minus half a kilo on the scales. Such an equation has existed in dietetics since the 50s, and it should have been broken and forgotten for a long time, but it does not work. Physiology is not mathematics, it cannot be calculated in absolute terms. Our body is cunning, it believes that fat accumulation is necessary for us, and diligently postpones them for a rainy day. They are like a survival insurance for him, it is inherent in genetics.
Therefore, it will not be possible to simply cut the diet and lose weight: even if the results are pleasing at first, after some time the plateau effect will inevitably come — the nightmare of all losing weight when the weight freezes in place, despite diet and physical exertion. And here it is necessary to give an additional boost to metabolism by reviewing not so much the caloric content as the qualitative components of nutrition.
If we continue to simply reduce caloric intake, the body will go into austerity mode, freeze many functions until better times, which can lead to a lot of negative consequences – from chronic fatigue and weakened immunity to fatal hormonal failure.
Does it make sense to count calories at all?
As a general, very approximate coordinate system, the caloric index somehow works. No one has canceled the rules “eat less, move more — it means you lose weight”.
But there are a lot of nuances. Let me remind you once again that the Atwater system, which underlies all modern labeling of calorie content of products, was developed almost a century and a half ago. But during this time, many of our knowledge about the world has gone ahead. For example, at the time of Atwater, science knew nothing about vitamins, dietary fibers, minerals and other micronutrients, that is, that not only the quantity but also the quality of food affects our weight and well-being.
Since then, humanity has been consuming much more “empty calories”, that is, refined sugar, butter, flour. Atwater, of course, could not have foreseen this. Today, many scientists believe that in order to maintain and adjust weight, it is important not so much to know the calorie content as the glycemic index of the product, which means the rate at which it increases the level of glucose in the blood. Refined products, which are rapidly processed and almost instantly absorbed into the blood, have this indicator much higher than those of the same products in their natural state. Thus, the glycemic index of purified white rice is almost one and a half times higher than that of brown rice, in which the shell of the grain is preserved, while the number of calories they have is about the same.
There is another pitfall in the established counting system, which in the language of dietetics is called the “Atwater trap”. The calculation does not take into account the physical condition and consistency of food. Today it has been proven that soft and heat-treated food is processed faster and more completely than raw and the one that needs to be eaten with jaws. So, in reality, it receives more energy than stated on the label. Let it be a fork of 10-20%, but over time, quite significant indicators are obtained. Japanese scientists conducted a very interesting study, however, not on humans, but on rats. They kept 20 rats on a feed of different consistency: half were given food in hard granules that had to be chewed, and the others were fed porridge-like food containing exactly the same substances and the number of calories. After 22 weeks, the rats from the soft food group weighed about 6% more than their relatives, and they had 30% more fat deposits than the animals from the control group, which meant the 2nd degree of obesity.
Simply put, you need to ask yourself not only the question “How many calories do I get?”, but also “From what source?”. 300 kcal in bran is not at all the same as 300 kcal in a muffin made of refined fine flour. And avocado fats cannot be qualitatively equated with fats from smoked lard, although they will be equal in absolute caloric values.
And finally, the most fundamental puncture. Today there is confirmed evidence that different components require different amounts of calories to digest. Fat is absorbed the fastest, followed by carbohydrates, and worst of all – proteins. The greater the proportion of protein in food, the higher the energy consumption for its digestion. Studies in recent years have shown that people whose food contained a lot of fat received the same weight gain as those who consumed almost five times more calories, but in the form of carbohydrates. That is, losing weight by replacing candy with nuts is not the best idea. Although this is not a reason at all to exclude from the diet, for example, butter or the same nuts: lack of fat, especially during periods of hormonal growth and decline, that is, during adulthood and, conversely, at a later age, negatively affects not only appearance, but also causes cognitive dysfunction, even developmental delay or premature senile dementia.
Then isn’t it easier not to limit yourself in food, but to burn excess calories in the gym?
Judge for yourself: in half an hour of intensive running on the track, 300 kcal are burned, about 700 kcal is consumed in an hour of lawn tennis, an hour of fast cycling we lose 600 kcal, climbing the stairs to the 5th floor – 400 kcal. How so? Did you sweat on the treadmill for half an hour, and “worked out” no more than half of yesterday’s eclair? Really, it’s a shame. But we, as it happened in the process of evolution, are extremely energy-saving designs. To maintain life, a person needs 20 times less energy relative to his own body weight than the same rat. After all, in ancient times a person was not brought food on a plate, he had to run around in order to find in the wild the same modest, as it seems to us now, 300 kcal. The desire to save energy is our genetics. All recent studies prove that physical activity can help solve a lot of problems: build a body relief, build muscle mass, maintain vascular and heart health, but, alas, demonstrates catastrophic inefficiency in terms of weight loss as such. If there is a specific goal — to lose weight, then on some workouts, without a properly structured diet, nothing will work.
By the way, do you know what is the most energy-intensive organ in our body? These are not biceps at all, but the brain, which eats from 200 kcal a day (in a state of sleep) to 1000 kcal (in a state of high tension: for example, during exams). So the expression “lose weight under stress” is not a figure of speech at all, but a scientifically based fact. But it is impossible to call such a method healthy, as soon as the situation normalizes, the body will quickly regain its spent fat reserves.
What could be the consequences of the fact that the concept of proper nutrition is increasingly reduced to a formal calorie count?
In this regard, one of the most harmful, in my opinion, trends of recent times is the appearance of so-called “low-calorie” products from which calories are artificially removed: “zero” curds, low-fat confectionery creams, light cheese options or butter spreads. In fact, these are deceptive products, because along with fats, fat-soluble vitamins are also removed from them, calcium and proteins that are in conjunction with fats, and many other valuable things will not be absorbed from them. In addition, it is fat that is known to be the main conductor of taste, so to imitate it, you have to add substitutes for everything: taste, density, smell.
But the main thing is that such castrated products do not give a feeling of satiety. In response, we either increase portions, or force our body to work in a mode of constant stress and lack of vital elements, thereby again sending it into a blind defense. Therefore, those who want to lose weight should first of all learn the axiom: you can effectively lose weight only on highly nutritious natural food, which correctly makes the metabolism work and normalizes lipid metabolism.
Are there any products with “negative calorie content”, which they write about so much?
This is a myth that contradicts physical laws. After all, how is “negative calorie content” usually defined? When more energy is spent on digesting a product than it brings into the body, that is, we eat and lose weight at the same time. Most often, this property is attributed to various fiber-rich vegetables and fruits like grapefruit, salad leaves, spinach, celery and others. But we know that the body spends no more than 20-30% of the energy entering it for digestion, and the remaining calories still remain with us. Another thing is that vegetable fibers really dull hunger, and more energy is spent on their processing than, for example, refined products, which is why fiber is so important for losing weight. But if you want to be not only thin, but also healthy, then the main thing is not to create a calorie deficit, but a balanced diet.