Base Weight; The Precondition Regarding the Rebound Effect


  1. Each person has the ability to maintain their present condition
  2. What makes the difference of each person’s base weight value?

1. Each person has the ability to maintain their present condition

First of all, I want to explain the most important point. It's the assumption that each person has the ability to maintain their present condition, also known as preserving current stasis in the body.
I recognize that this is the precondition of everyone regarding weight control.

For example, there are three women:

(A) 48kg・・・who can't gain weight even if she eats a lot.
(B) 58kg・・・who can easily gain two kilos if she lets her guard down and eats a little more.
(C) 85kg・・・                   〃

All through the year, we get thinner when we are busy, and we gain a little fat when we aren’t active and eat a lot. Although everyone repeats the same pattern, even if we don't calculate calories strictly, the body shape of person won't change so easily. Fat people are fat and thin people are thin. 

In other words, I believe that each person has a stable weight based on their body's homeostatic functions, which I define as their "base weight."

[Base weight] = The stable weight one returns to after spending 3-5 days relaxing without excessive exercise or work, while consuming calories based on their daily energy needs.

(Note: The concept of a "set point for body weight" exists among some researchers, which is essentially synonymous with this idea.)

In this example, Person A's base weight is forty-eight kilograms. However, for Persons B and C, the weights they quickly revert to when they let their guard down and eat a lot—sixty kilograms and eighty-seven kilograms, respectively—can be considered their actual "base weight." This means that their homeostatic functions are working to maintain those weights. 

So, it’s difficult to assume a person’s body and weight condition only with caloric intake.

Consider the example above, that if A continues an intake of 100kcal over her recommended daily caloric intake every day for several months or years, the assumption is that it will accumulate into fat and she will eventually gain weight up to the eighty-kilogram level. This is wrong (She might gain weight but that is a different mechanism).


Base weight-2
Base weight-1

In general, people who are overweight are more likely to be restricting calories and eating modestly, so their current weight is often lower than their base weight. On the other hand, thin people don't have caloric restrictions, so their current weight and their base weight are often close

Therefore, ‘thin A’ won't gain weight even if she eats a lot, and B and C will gain weight immediately as soon as they eat a lot.

▽Example of Hozumi Hasegawa, the professional boxer who defended his title ten times as the twenty-sixth Champion of WBC World bantamweight class.

The Bantamweight limit is fifty-three-point-five kilograms(53.5kg). As his body got older, losing weight became harder. For a defending match, he had to lose more than ten kilograms in a month. 

But, as soon as the match was over and he started to eat, his weight increased ten kilograms in a few days. The rate of going back to his base weight was fast. Those who have tried diets and eat less than usual might have experienced this. Often, it's called the rebound effect.

2. What makes the difference of each person's base weight value?

I arrived at this idea of "base weight" through my own experience and by observing people around me, but according to Dr. Jason Fung, the author of “The Obesity Code,” in 1984, two researchers, Keesey and Corbett, first proposed that there is a "set point" for body weight and fatness. 

According to this idea, homeostatic mechanisms in the human body work to defend this body set weight against changes. 

Set weight

When caloric intake is reduced and weight drops below body set weight, the basal metabolism begins shutting down to conserve energy and appetite is increased, which causes body weight to return to its base.

When caloric intake is increased and weight goes above body set weight, the basal metabolism activates and the appetite decreases to lower to the original body set weight[1].

However, I have a different view about it.

It makes total sense that when the body has less energy available, it lowers its metabolism to conserve energy expenditure, and that when you eat a lot, your basal metabolism conversely increases, but isn't that a consequence of what happens in the body when you increase or decrease your intake of calories? That idea may explain the rebound effect after dieting, but it does not explain the fundamental difference between fat and thin people-the reason why some people gain weight. 

I believe that each person's base weight (set weight) value is determined by the absorption ability of the   intestines (the small intestine is also known as the "second brain”). This is my conclusion from my own experience, and I believe I can prove that theory with the help of experts.

[1] Dr. Jason Fung, The Obesity Code, 2016, Page 62