Misunderstanding of the Relationship Between Diet, Exercise, and Body Weight


  1. The relationship between “diet and exercise” is the most commonly used excuse
  2. Expended energy will be regained
  3. What does “diet is the priority” mean?
    The bottom line


The fact that many people who play sports are lean, and that we see athletes who have gained a lot of weight after retiring from active sports, seems to make the formula 'exercise = losing weight' true.

Most experts see it this way, but the relationship between exercise and weight should not be as simple as this.

However, with my three-basis theory, that is to say: 1) each person has the ability to maintain their present condition (base weight) ; 2) the phrase “gain weight” has two meanings ; 3) base weight value increases by inducing intestinal starvation, it becomes much easier to explain the relationship between diet, exercise, and body weight.

1. The relationship between “diet and exercise” is the most commonly used excuse, for specialists 

see a doctor

First of all, for those who have not lost weight even after exercising, physicians and specialists would say, "After all, you must be eating a lot somewhere," and for those who have not lost weight even after restricting calories, they would say, "You are not exercising enough, are you?" 

That is to say, the relationship between diet and exercise has been regarded as a "calories-in/calories-out" relationship, which has been used as an excuse by experts, and the relationship has not even been considered in an in-depth manner.

2. Expended energy will be regained

I repeat, but those who believe that, "eating more will always make you gain weight/ exercising more will help you lose weight," see it as shown in Figure-1

calories in,out


They tend to think that "caloric Intake and burned calories" are opposites, and you will gain (or lose) weight depending on the relationship between the two.

In reality, however, it should be like Figure-2.

Energy circulates(1)


Since “foods we eat” and “the energy used in our body” are mediated by absorption, an increase in energy expenditure will increases absorption rate, which in turn work up an appetite .

In contrast, if you increase the amount and frequency of eating when you are at rest and not hungry, the absorption rate will decrease.

Exercise certainly consumes more energy, but the opposite reaction-that the body tries to regain energy that it has expended-should work.

In other words, exercise is essentially a force that pushes the body in the direction of gaining strength (and ultimately, storing energy and gainning weight) as it tries to re-energize the body and restor energy circulation. (In particular, it works more strongly in resistant exercises such as lifting weights.)

However, whether or not you gain weight depends on how you control the way you eat.

Diet” is always the priority.

This is why false theories emerge like, “people exercising everyday are lean, even if they eat a lot.”

3. What does “diet is the priority” mean?

The simple explanation is that even though exercise is powering the body to store energy, if some undigested food is always left in the intestines, as a result, intestinal starvation does not occur and the base weight value remains the same.

I will explain this in greater detail several ways.

(1) Not gaining weight while doing exercise

As Dr. John Briffa, the author of “Escape the Diet Trap,” says in his book, it is better to think that, "originally lean people start running marathons or playing soccer, etc. and eventually become athletes.”[1]
It may be a cynical view, but I think it’s probably correct. 

What’s more, they know they never gain weight even though they eat a lot, and most athletes eat three well-balanced meals, plus other nutritional supplements and snacks. 

Japanese breakfast

(Traditional Japanese breakfast)

This is because when we try to exercise, our mindset is that we need to be nourished and that we need to eat well. 

In other words, a person who is originally lean can maintain the same weight over the years because their base weight does not increase by eating well-balanced meals three times a day (some undigested foods tend to remain in their intestines throughout the day) .

(2) Putting on some weight after quitting exercise 

On the other hand, there are athletes who say they have put on weight since retiring from active sports, and others who say they have gained weight because they work at a desk and have not been exercising recently. 

However, skipping meals, eating light meals, eating a carbohydrate-heavy diet, or irregular eating habits are more of a problem than not exercising. This is because the intestinal starvation mechanism is more likely to be induced. 

Desk work

When we have nothing to do or do light physical work all day, we tend to think that we need to eat less, don't we?

Perhaps some people might go to work without breakfast, or have a simple lunch such as ramen noodles or a hamburger.

In this case, the body's ability to take in nutrients is low compared to when exercising, but on the other hand, intestinal starvation is more likely to occur, and in the long run, the body is more likely to gain weight. 

There are people who say, "When I was young I didn't gain weight even if I ate a lot, but recently I’m gaining weight because I haven’t exercised.”
But in other words, it means that they didn’t gain weight when they were young since they ate well-balanced meals a few times a day, but now they are eating light meals (not enough vegetables) and are experiencing being hungry over many hours, so they’re gaining weight.


(3)Gaining weight while doing exercise

Fighters and sumo wrestlers exercise, of course, and they need to gain weight due to the nature of their sports.

However, we often hear that it’s not easy for some of them to gain muscle and weight even if they eat a lot of meals and protein supplements. 

On the other hand, those who don’t want to gain weight, sometimes put on weight easily. This is because, as I have mentioned so many times, the intestinal starvation mechanism is necessary in order to gain weight. 

High-intensity exercise using barbells,etc. is more of a force accelerating to the direction of gaining strength than aerobic exercise, but if you eat balanced meals including high-calorie foods and protein supplements every four to five hours every day in order to gain weight, some undigested foods tend to remain in your intestines throughout the day. And it can hinder inducing intestinal starvation.

An example of sumo wrestlers

Sumo wrestlers (Japanese national sport) are famous for being big, but their main diet traditionally consists of a lot of rice and hot-pot dishes called “Chanko” (stewed chicken meat and vegetables, etc.) which is easy to digest. 

In addition to this, they always do early morning practice, not eating breakfast. They eat only twice a day(at eleven am and six pm) after practice.

Therefore, the food they eat can be more easily digested in the entire intestines and their base weight value tends to increase. 

In this case, we can say that the "fattening force" of exercise and the "starvation mechanism" are pointed in the same direction. That is to say, it is a logical way to increase muscle strength and weight.

[1]Escape the Diet Trap, Dr. John Briffa, 2012, Page 223. 

The bottom line

(1)The relationship between diet and exercise is not simply an energy "in/out" relationship.
Exercise is essentially a force that works toward gaining strength (and weight) because the opposite reaction-that the body tries to regain energy that it has expended-should work (especially in the case of high-intensity exercise).

(2) However, the priority is in how we control our diet. The way we control our eating habits (what to eat, when to eat, how to eat, etc.) has a huge effect on whether we gain weight or not. 
People who are originally lean start athletics, soccer, etc., and if they eat three well-balanced meals every day, they are less likely to gain weight and maintain the same body shape over the years.

(3) Some people who live a sedentary life or do light physical work tend to eat less or skip meals.
In this case, the body's capability to absorb and store fat is actually lower than during exercise, but they end up feeling hungrier and intestinal starvation is more likely to be caused, resulting in an increase in one's base weight.