There is No Meaning in Simply Calculating Calories You Consume


  1. The Atwater coefficient is based on averages
  2. How we digest food and absorb it differs in each person
  3. The fundamental cause of obesity can be explain by base weight value
    The Bottom Line

I’d like to talk about how meaningless it is to calculate the accurate caloric intake for the day, and apply it to weight control to lose weight.

It is said that the caloric values of food that we use to calculate caloric intake are based on the Atwater system(the coefficient of 4 kcal/g for protein and carbohydrate, 9 kcal/g for fat, and 7 kcal/g for alcohol), but various problems have been pointed out regarding the accuracy of these factors.

[Related article]
  Calorie Calculation: Why the Atwater Coefficient Is Not Perfect

I believe that one of the problems is that digestibility and absorption rates are based on a system of  averages, and I would like to explain that. (This article focuses on how people absorb energy differently, and I won’t mention the process after absorption such as the metabolic process or the differences in hormone secretion, etc.)

1.The Atwater coefficient is based on averages

Daily caloric intake

It is said that, "if you take in more calories than your body needs, you will gain weight, and if you burn more calories than you take in, you will lose weight."(Note 1) This message is very simple, and in a way, it sounds very direct.

However, it is dangerous to accept because the phrases "calories your body needs," and "calories you take in," are ambiguous.

It is said that the calories that the body actually expends including basal metabolism are constantly changing[1], and in my opinion, the calories that the body actually absorbs from food are constantly changing as well.

So, I think it is difficult to derive an accurate value by simply comparing total caloric intake and expenditure.

The Atwater coefficient is based on the average energy value that we can absorb from food, but it seems like it has not been investigated how the absorption rate varies depending on what time of day you eat, how often you eat, or how you combine other foods in a meal.

Also, since this factor is calculated from an average of the subjects, it assumes that everyone has the same digestion and absorption ability[2].

<Note 1>
In 1878, German nutritionist Max Rubner crafted what he called the "isodynamic law".[1] The law claims that the basis of nutrition is the exchange of energy,[2] and was applied to the study of obesity in the early 1900s by Carl von Noorden.(Wikipedia [A calorie is a calorie])

2. How we digest food and absorb it differs in each person

Because I was very thin, my digestibility was poor, and I often had gastrointestinal problems. I felt like I was a guinea pig. If I ate too much fatty or fibrous food, my stomach would be upset even after several hours. And if I forced myself to eat my next meal in that state, I felt that I lost even more weight.

In the Atwater coefficient, fat is said to have a caloric value of 9 kcal/g because its physical combustion heat is 9.4 kilo calories and its digestibility coefficient is set at 95% [3], but for people who have trouble digesting it, including myself, that number is meaningless. 

In the following, I will explain how our absorption rate varies for an individual based on my experience.

(I)  Absorption rate is not constant but increases from hunger or exercise

Some experiments have shown that when people who want to lose weight reduce their caloric intake and semi-starve themselves, their basal metabolic rate also decreases[1], but I do believe that the absorption rate also changes.

The absorption rate should increase during prolonged periods of hunger or after exercise. This, I believe, is true, not only for energy sources but also for all nutrients, including calcium and other micronutrients.

When you are too hungry and tired, your body is working hard trying to take in more nutrients; if you drink alcohol, you may get pretty intoxicated, or if you eat ramen noodles or sweets, your blood sugar level may spike.

Blood glucose level

To be more specific, even if you reduce the 700 kcal lunch to 400 kcal and eat nothing until dinner, there is still breakfast in your gut, and your intestines wil be working really hard to take in nutrients out of what is left. 

Even when the body uses stored energy sources, not all of them lead to a reduction in body fat because some energy sources are used first. In addition, I believe, the more hunger continues, the higher the absorption ability after dinner is, so the body fat should not be reduced as calculated even if the reduced 300 kcal of energy each day is totaled, for instance, for a two-week period.
(The body is said to be in equilibrium with less weight loss than expected, since the basal metabolism also decreases along with weight loss.)

On the contrary, if you continue to force yourself to eat every three to four hours even though you are not feeling hungry, your absorption rate will decrease, relatively speaking. (Of course, it differs from person to person.)

Consider this for instance, after we eat food, it digests for a few hours, and finally, when it is starting to be  absorbed, another food comes into the stomach. So, the body will perceive that, “here comes some more food... we can simply take nutrition from that.”

In the previous example of blood glucose, if you eat ice cream two hours before a meal, the rise in blood glucose levels at the meal should slow down. 

Protein Supplement

While a person doing intense exercise with barbells may need to drink protein and milk between meals, the average person doing light exercise may lose weight from this type of eating because the absorption rate decreases, and energy for digestion (diet-induced thermogenesis) is increased, which can be beneficial for weight loss! 

(II) The absorption rate varies depending on the combination of foods

How we combine different foods in a meal also makes a difference in hunger and the absorption rate.

As an example, consider a 400 kcal of breakfast (a slice of toast, ham, fried egg). Even if the caloric intake increases, I think adding a burdock salad, cheese, beans, sautéed mushrooms, etc., to breakfast will suppress hunger at lunch and help reduce the rise in blood glucose levels.

I believe it’s partly because that by constantly eating indigestible foods that contain a lot of fiber, or foods that take a long time to digest, undigested food will remain in the gut which suppresses hunger and decreases the absorption rate. It might also be possible that the fiber itself slightly hinders absorption.

Fibrous vegetables

Therefore, even if caloric intake is increased, adding these foods to the three daily meals can still be beneficial for dieting.

Conversely, even if caloric intake is reduced, eating only fiber-poor and highly processed foods which are digested quickly give us a lot of energy for very little work[4]. It may increase the absorption rate because of the constant feeling of hunger, and in turn, it may result in repeated ups and downs in blood sugar levels.

(III) Fat does not always make you fat

How we combine macronutrients such as carbohydrates, proteins, and fats in a meal also makes a difference.

Based on calorie theory, we are taught by nutritionists, doctors, and TV programs, that "if you eat a lot of fat, you will get fat" because fat has nine kilo calories of energy per gram.

However, studies have repeatedly shown until the 1970's that diets that reduced carbohydrates and increased protein and fat as much as one wanted, as seen in carbohydrate-restricted diets, had caused weight loss in subjects, even though their daily caloric intake increased[5].

The DIRECT (Dietary Intervention Randomized Controlled Trial) study conducted in Israel in 2008 also confirmed that the "Mediterranean Diet" and the "Atkins Diet" (low carbohydrate) had a greater effect on body fat loss than the "low-fat diet" [6 ].

Of course, it is known that the energy to digest protein (diet-induced thermogenesis) is higher and that it makes a difference in the hormones stimulated, but what I’d like to add is the absorption factor.

For the same reason as the indigestible fibrous foods in section (2) above, a diet with less easily digestible refined carbohydrates and relatively more indigestible fats and meats (especially unprocessed slabs or chunks), etc. will reduce hunger, decrease absorption, and help you lose weight because the undigested food will remain in the gut for longer periods of time. More benefits should be obtained by incorporating fat into each meal or even between meals as snacks.

Of course, this effect may be less pronounced for people or ethnic groups that can digest fat and protein quickly, but for those who cannot digest fat quickly, including myself, consuming more fat will not cause weight gain.

I believe this may be related to data showing that in the U.S., the rates of obesity defined as having a body mass index of thirty or more increased dramatically from 1977 as a result of the promotion of low-fat diets (high carbohydrate) between 1976 and 1996 [7].

[Related article] Eating Fat/Oil Is a Deterrent to Gaining Weight

3.The fundamental cause of obesity can be explain by base weight value

The explanation in section 2 above is how the absorption rate changes in an individual, but as I’ve mentioned throughout this blog, the fundamental difference between overweight and thin people can be explained by the difference in base weight value.

Two meaning to the phrase 'gaining weight'

When you gain or lose some weight depending on the amount of calories ingested or burned, I believe it is within the range of [A] ( blue arrow in the figure). 

But the increase in base weight itself is not directly related to the amount of calories you take in, because it is induced by the intestinal starvation mechanism.

And my theory is that this higher base weight means a state of "absolutely higher absorption" than a person of average weight, and since I believe that all nutrients are increased, the increase in weight is related not only to body fat, but also to increased muscle mass.

At this point, I can't point out the discrepancy in the Atwater coefficient to explain how one’s base weight changes, but I would certainly like to prove that people can gain weight due to intestinal starvation.

[1] Jason Fung, The Obesity Code, 2019, P.67.
[2] Rob Dunn,"Science Reveals Why Calorie Counts Are All Wrong",2013.
[3] Japan Food Research Laboratories, 「The Energy Content of Food (食品のエネルギーについて)」,2003.
[4] Rob Dunn,"Science Reveals Why Calorie Counts Are All Wrong",2013.
[5] Gary Taubes, Why We Get Fat, 2013, P164-175.
[6] Jason Fung, The Obesity Code, 2019, P.177-179.
[7] Jason Fung, The Obesity Code, 2019, P.54-55.

The Bottom Line

(1)While it makes sense to calculate daily caloric intake as an average guide in the case of mass food preparation (school lunches, elderly homes, etc.), it does not make much sense to apply it for dieting for each individual. There are many other problems in the concept of being overweight.

(2)The Atwater coefficient is based on the average subject’s ability to digest food , but the process of human digestion and absorption is complex and cannot be described by a system that consist of an average value.

(3)In my opinion, one’s absorption rate varies with how hungry you feel and the intensity of exercise you do. Moreover, what time of the day you eat, meal intervals, and which different foods are combined in a meal also affect the outcome.

(4)I believe that the fundamental cause of being overweight can be explained by "higher base weight," and reducing caloric intake may result in temporary weight loss, but in the long run, it will not be effective.