— Topics —
Exercise, Workouts


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 “gaining 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.

Two meaning to the phrase 'gaining 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.

Jone Briffa. Escape the Diet Trap. London: Fourth Estate, 2013, 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.


For Dieting, Meal Improvement Rather than Exercise


  1. Little benefit of expended calories
  2. Improving diet is more important
     (1) Deceived by hype
     (2) When proposing exercise, always provide meal coaching, too
    The bottom line

Please read Is Exercise Really Necessary to Lose Weight?, first.

In the above article, we considered how exercise can really help people lose weight, but let's explore that in more detail.

1. Little benefit of expended calories

"A 250-pound man will burn three extra calories (kcal)climbing one flight of stairs, as Louis Newburgh of the University of Michigan calculated in 1942.

“He will have to climb twenty flights of stairs to rid himself of the energy contained in one slice of bread!” 

So why not skip the stairs and skip the bread and call it a day?

After all, what are the chances that if a 250-pounder does climb twenty extra flights a day he won't eat the equivalent of an extra slice of bread before the day is done?"
(Gary Taubes. Why We Get Fat. New York: Anchor Books, 2011, Page 48.)

"Other experts took to arguing that we could lose weight by weightlifting or resistance training rather than the kind of aerobic activity, like running, that was aimed purely at increasing our expenditure of calories.

The idea here was that we could build muscle and lose fat, and so we'd be fitter even if our weight remained constant, because of the trade-off. Then the extra muscle would contribute to maintaining the fat loss, because it would burn off more calories—muscle being more metabolically active than fat.

resistance training

To make this argument, though, these experts invariably ignored the actual numbers, because they, too, are unimpressive.

If we replace five pounds of fat with five pounds of muscle, which is a significant achievement for most adults, we will increase our energy expenditure by two dozen calories(kcal) a day. 

Once again, we're talking about the caloric equivalent of a quarter-slice of bread, with no guarantee that we won't be two-dozen-calories-a-day hungrier because of this.

And once again we're back to the notion that it might be easier just to skip both the bread and the weightlifting."
(Taubes. Why We Get Fat. Pages 54-5.)

2. Improving diet is more important

Walking, jogging, and other forms of exercise are undoubtedly necessary for the prevention of chronic diseases, and for mental and physical health, but as we reviewed in detail in section[1] above, they are not that effective in terms of caloric expenditure.
I suspect that t
hose who say that they have lost weight through exercise are doing so through a set of dietary improvements (such as balanced diet and how often they eat, etc.)

There is a book written by a Japanese exercise specialist, Takuro Mori, on this subject, and I would like to dive deeply into this:
Sports coach declares. For dieting, exercise should be ten percent and meals should be ninety percent 

Mr. Mori worked in a fitness club for five years, and though he is a sports coach, he says it’s impossible to lose weight only with exercise.

(1) Deceived by hype

“As an exercise instructor, I’ve seen hundreds and thousands of clients. However, what I saw there were long-time club members who had not gotten slim, and moreover, some staff who had not lost weight despite the fact that they worked as coaches in a sports club.(*snip*) 

The key to successful dieting is mostly the improvement of diet and the mentality to support it. 

As for exercise, I believe that it is very small in comparison to those two factors, and if we can manage to improve diet and mentality, we can get mostly good results, even if we omit the exercise guidance.

It is also true that I was deceived by various diet-related hype and believed, unknowingly, that anyone could lose weight with effective exercise....(omitted) 

That is just an advertisement, so it is natural that it is an exaggeration to attract customers. Because of that, it’s manipulating people’s general perception.”

(2)When proposing exercise, always provide meal coaching, too

Through my past exercise and diet coaching, I have become acutely aware that most people actually do not achieve results with only exercise. As I interacted with many clients, I began to see a trend in those who failed to achieve results.
They all had problems in their eating habits such as they kept eating what they liked or didn’t want to change their eating habit.

Considering the body's mechanism for losing weight, there is no more effective way to lose weight than by controlling diet, and the appropriate approach is to add the necessary amount of exercise to it.

If you pick up any diet book on the street, you will find that most of them refer to diet, even if they explain a particular exercise regimen.

Successful dieters lose weight by improving their diet (eating a balanced diet and eating more often, etc.), not by exercising. (*snip*)

It is necessary to understand the basic premise that exercise creates a beautiful body style, and if you want to lose weight and size, you must improve your diet and other aspects of your life."[1]


This is what I wanted to tell you, but I had to quote an exercise expert because he is more convincing.

Diet books that claim, "you can lose weight with exercise," always mention improving your diet. 
The trend these days seems to be changing to eating fewer carbohydrates, and eating more protein (meat, eggs, etc.), vegetables, dairy products, etc., while exercising. 

You might think that exercise has contributed significantly to your weight loss since you lost weight by eating enough, but you would be mistaken.

It may be better to think that changing your eating habits can actually help you reduce weight and size, and that exercise is more about building a lean, toned body while you lose weight.

[1]Takuro Mori. For dieting, exercise should be ten percent and meal should be ninety percent (森 拓郎,「ダイエットは運動1割、食事9割」). 2013. 

The bottom line

(1) Calories burned in exercise are not that many . Those who exercise but do not get results from dieting often have some problem with their eating habits, such as wanting to lose weight while eating what they like.

(2) To lose weight, it is more effective to review one's daily eating habits. Reducing carbohydrate intake to some extent and increasing protein, fat, dairy products, and vegetables can be helpful.
On the other hand,
 exercise helps to improve overall health, maintain muscle strength, and build a toned body.

(3) The reason exercise is not fundamentally helpful for weight loss is because the relationship between diet, exercise, and weight is misunderstood.

[Related article]   Misunderstanding of the Relationship Between Diet, Exercise and Body Weight


Is Exercise Really Necessary to Lose Weight?


  1. Exercise is good for your health, but what about losing weight?
  2. Some reasons to doubt the weight-loss benefits of exercise
  3. Energy expenditure and intake are closely linked
  4. Evidence that exercise has no effect on weight loss was ignored
    The bottom line


"Imagine you're invited to a celebratory dinner.

The chef's talent is legendary, and the invitation says that this particular dinner is going to be a feast of monumental proportions. Bring your appetite, you're told—come hungry.
How would you do it?

You might try to eat less over the course of the day,—maybe even skip lunch, or breakfast and lunch. You might go to the gym for a particularly vigorous workout, or go for a longer run or swim than usual, to work up an appetite. You might even decide to walk to the dinner, rather than drive, for the same reason.

Now let's think about this for a moment. The instructions that we're constantly being given to lose weight–eat less and exercise more —are the very same things we'll do if our purpose is to make ourselves hungry, to build up an appetite, to eat more.

Now the existence of an obesity epidemic coincident with half a century of advice to eat less and exercise more begins to look less paradoxical."
(Gary Taubes. Why We Get Fat. New York: Anchor Books, 2011, Page 40.)

1. Exercise is good for your health, but what about losing weight?

“It's now commonly believed that sedentary behavior is as much a cause of our weight problems as how much we eat. And because the likelihood that we'll get heart disease, diabetes, and cancer increases the fatter we become, the supposedly sedentary nature of our lives is now considered a causal factor in these diseases as well.
Regular exercise is now seen as an essential means of prevention for all the chronic ailments of our day.

(*snip*)Faith in the health benefit of physical activity is now so deeply ingrained in our consciousness that it's often considered the one fact in the controversial science of health and lifestyle that must never be questioned.(*snip*)

But the question I want to explore here is not whether exercise is fun or good for us or a necessary adjunct of a healthy lifestyle, as the authorities are constantly telling us, but whether it will help us maintain our weight if we're lean, or lose weight if we're not.
The answer appears to be no. (*snip*)

Malathon runner

The ubiquitous faith in the belief that the more calories we expend, the less we’ll weigh is based ultimately on one observation and one assumption.

The observation is that people who are lean tend to be more physically active than those of us who aren't. This is undisputed. Marathon runners as a rule are not overweight or obese.

But this observation tells us nothing about whether runners would be fatter if they didn't run or if the pursuit of distance running as a full-time hobby will turn a fat man or Woman into a lean marathoner."
(Taubes. Why We Get Fat. Page 41, 46.)

2. Some reasons to doubt the weight-loss benefits of exercise

In the following article, I believe I mentioned that adding exercise to a conventional calorie-restricted diet has not been very effective, and I will try to explore why. I would like to address the following five points.
【Related article】  Dieting Doesn’t Work in the Long Run

(I)Overweight among the poor

"In the United States, Europe, and other developed nations, the poorer people are, the fatter they're likely to be. It's also true that the poorer we are, the more likely we are to work at physically demanding occupations, to earn our living with our bodies rather than our brains. (*snip*)

They may not belong to health clubs or spend their leisure time training for their next marathon, but they're far more likely than those more affluent to work in the fields and in factories, as domestics and gardeners, in the mines and on construction sites. 

manual labor

That the poorer we are the fatter we're likely to be is one very good reason to doubt the assertion that the amount of energy we expend on a day-to-day basis has any relation to whether we get fat.

If factory workers can be obese, as I discussed earlier, and oil-field laborers, it's hard to imagine that the day-to-day expenditure of energy makes much of a difference. "
(Taubes. Why We Get Fat. Page 41-2.)

(II) Exercise makes you hungrier

Many people have probably realized that exercise and manual labor will make them feel "hungrier" and have a greater appetite than in a sedentary life such as a desk job. Some of you may have exercised to lose weight, but ended up eating chocolate or other sweets because you were tired and then regretted your own weak will and "lack of self-control.”

However, I believe that these are the correct mechanisms for humans. I will explore this issue in more detail in the next section 3.
(III) Increased absorption rate

The effect of aerobic or anaerobic exercise on body fat loss is said to be different, but either way,  I believe the energy once expended through exercise will basically come back

Energy circulates

When we exercise, our muscles need energy. Depending on the intensity of the exercise, energy is produced mainly from blood glucose, muscle glycogen, and fatty acids from fat cells. Of course, energy expenditure will increase once, but then I believe the body will increase its absorption rate to absorb more nutrients from food in the intestines to compensate for those lost nutrients.

Increased absorption rate” might be difficult to understand but think of it this way: When a person drinks alcohol on an empty stomach or drinks alcohol after exercising, it will make them more intoxicated or a person turns redder than usual (AKA the Asian glow)

And, if you are not a drinker, eating or drinking something sweet after exercise may cause your blood sugar to rise more rapidly than usual.

(IV) Become less active at other times

It is said that when people increase their amount of exercise, they naturally tend to become inactive the rest of their lives.

For example, after completing a thirty-minute jog, one may end up relaxing on the couch for a couple of hours because of the fatigue, or may become less active than usual over the course of the day.[1]

relaxing on a couch
(V)Small amount of body fat burned

Body fat is a stored form of energy, so it is not used immediately. Therefore, in the case of high-intensity anaerobic exercise that stresses the muscles, ATP and creatine phosphate stored in the muscles are used as an energy source for about 15 seconds from the start. After that, what is being expended is blood glucose and glycogen, the fast-acting energy source stored in the muscles.

In aerobic exercise such as jogging, which is said to burn more body fat, there is a concept of a fat-burning zone (low-intensity exercise that keeps your heart rate between 60 and 69 percent of  maximum heart rate), but even in this case, about fifty percent of the calories burned come from fat.[2].

Even if the calories burned in thirty minutes of jogging are two hundred kcal, that does not all translate into a reduction in body fat.

3. Energy expenditure and intake are closely linked

In section [2] above, I explained about increased absorption rate, having a bigger appetite, and becoming inactive after exercise, but I will quote again from "Why We Get Fat" for a more scientific explanation.

"The very notion that expending more energy than we take in-eating less and exercising more-can cure us of our weight problem, make us permanently leaner and lighter, is based on yet another assumption about the laws of thermodynamics that happens to be incorrect. 

The assumption is that the energy we consume and the energy we expend have little influence on each other, that we can consciously change one and it will have no consequence on the other, and vice versa. (*snip*)

Intuitively we know this isn't true, and the research in both animals and humans, going back a century, confirms it. People who semi-starve themselves, or who are semi-starved during wars, famines, or scientific experiments, are not only hungry all the time but lethargic, and they expend less energy. And increasing physical activity does increase hunger; exercise does work up an appetite. (*snip*)

In short, the energy we consume and the energy we expend are dependent on each other. Mathematicians would say they are dependent variables, not independent variables, as they have typically been treated. Change one, and the other changes to compensate. (*snip*)

Anyone who argues differently is treating an extraordinarily complex living organism as though it were a simple mechanical device. (*snip*)

In 2007, Jeffrey Flier, dean of Harvard Medical School and his wife and colleague in obesity research, Terry Maratos-Flier, published an article in Scientific American called “What Fuels Fat.”

In it, they described the intimate link between appetite and energy expenditure, making clear that they are not simply variables that an individual can consciously decide to change with the only effect being that his or her fat tissue will get smaller or larger to compensate. "
(Taubes. Why We Get Fat. Page 77-8.)


4. Evidence that exercise has no effect on weight loss was ignored

"As it turns out, very little evidence exists to support the belief that the number of calories we expend has any effect on how fat we are.

In August 2007, the American Heart Association (AHA) and the American College of Sports Medicine (ACSM) addressed this evidence in a particularly damning manner when they published joint guidelines on physical activity and health. (*snip*) Thirty minutes of moderately vigorous physical activity, they said, five days a week, was necessary to “maintain and promote health.”

But when it came to the question of how exercising affects our getting fat or staying lean, these experts could only say: “It is reasonable to assume that persons with relatively high daily energy expenditures would be less likely to gain weight over time, compared with those who have low energy expenditures. So far, data to support this hypothesis are not particularly compelling." (*snip*)

From the late 1970s onward, the primary factor fueling the belief that we can maintain or lose weight through exercise seemed to be the researchers' desire to believe it was true and their reluctance to acknowledge otherwise publicly. 

Although one couldn't help being “underwhelmed” by the actual evidence, as Judith Stern, Mayer's former student, wrote in 1986, it would be “shortsighted” to say that exercise was ineffective, because it meant ignoring the possible contributions of exercise to the prevention of obesity and to the maintenance of any weight loss that might have been induced by diet. (*snip*)

As for the researchers themselves, they invariably found a way to write their articles and reviews that allowed them to continue to promote exercise and physical activity, regardless of what the evidence actually showed. 

One common method was (and still is) to discuss only the results that seem to support the belief that physical activity and energy expenditure can determine how fat we are, while simply ignoring the evidence that refutes the notion, even if the latter is in much more plentiful supply."
(Taubes. Why We Get Fat. Page 43-4, 53-4.)

[1]Dr. John Briffa. Escape the Diet Trap. 
London: Fourth Estate, 2013, Page 222.

[2]University of Hawai‘i at Mānoa Food Science and Human Nutrition Program.「Fuel Sources for Exercise」. 2018.

The bottom line

(1) The idea that the more calories we burn, the lighter we weigh is based on the observation that "lean people tend to be physically more active than those who are not." However, there is little evidence to support this.

(2) Everyone would probably agree that "lean people tend to be more physically active than those who are not." However, it is not as simple as, "if you increase caloric expenditure through exercise, you will lose weight.” The relationship between exercise and weight is more complex.

【See more】Misunderstanding of the Relationship Between Diet, Exercise and Body Weight

(3) Calories consumed and calories expended are interconnected, and if you exercise more, you will feel hungrier and have a bigger appetite. Even if you keep your caloric intake the same, your body will try to regain lost energy source and nutrients due to increased absorption rate after exercise.

(4) The problem with being overweight is that one's base weight value is elevated, and while energy expenditure through exercise may lead to temporary weight loss, it is not effective in the long run. 
As we’ll see in more detail in the following blogs, it is more important to improve dietary balance and intake methods (when or how often you eat, etc.) in combination with exercise.

【Related article】   For Dieting, Meal Improvement Rather than Exercise