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03/03/2016

The Set-Point Weight; The Precondition Regarding the Rebound Effect

Contents

Each person has the ability to maintain their present condition
Encounter with the set-point theory

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 initially defined 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.

However, despite the lack of official proof or definition, some researchers have already used the concepts of 'set-point weight.' Additionally, my "base weight" can be confused with "baseline weight," which is used in some studies. Therefore, I will use 'set-point weight' or ‘set-point’ for body weight going forward."

In this example, Person A's set-point 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 set-point 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).

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 set-point weight. On the other hand, thin people don't have caloric restrictions, so their current weight and their set-point weight are often close. (Temporary overeating may lead to further weight gain beyond the body’s set-point, but I believe this weight gain is temporary and does not alter one’s set- point weight.）

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 set-point 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. Encounter with the set-point theory

Most of us do not consciously adjust our daily energy intake and expenditure. Nevertheless, an individual's body weight remains relatively stable.

Individual body weight variance is typically only 0.5% over periods of 6 to 10 weeks[1,2] (Khosha and Billewicz 1964). According to cross-sectional data, weight changes over longer periods of time are still modest, and even diabetic individuals display coefficients of body weight variation of only 3.7– 4.6% over a period of five years[1,3] (Goodner and Oglive 1974).

With the global increase in obesity since the 1970’s, these coefficients of body weight variation may no longer be as accurate. However, many people still stay lean (especially in Asia), and, in fact, even those who are overweight or obese manage to maintain their weight, heavy as they may be, for many years[4].

In other words, despite some fluctuations in weight in daily life, there must be an internal regulatory mechanism that works to keep weight and fat within a certain range over the long haul.

■In recent years, the role of homeostatic regulation has been acknowledged, and there is growing evidence that the body employs physiological mechanisms to control energy balance and maintain body weight at a genetically and environmentally determined "set-point."[5]

When a person loses weight, the body substantially lowers energy expenditure, often more than expected based on changes in body composition or the thermic effect of food.

Additionally, it triggers hormonal changes that increase appetite and modifies food preferences through behavioral adaptations, aiming to restore body weight to its set-point range[6].

This feedback mechanism is known to apply not only to weight loss but also to temporary overeating[7].

When I started writing this blog, I had no knowledge of the theory about the body's "set-point," but it almost aligned with what I had always believed. I now believe that understanding the set-point theory is crucial in preventing the spread of obesity and proposing effective weight loss methods.

In particular, to explain the global rise in obesity since the 1970’s, I believe it is essential to understand how (I) genetic and biological factors, and (II) environmental and behavioral factors combine to increase the body’s set-point for weight. I believe my intestinal starvation theory can contribute to this understanding.

For more details, please refer to the articles below.

References：
[1]Richard E. Keesey, Matt D. Hirvonen. Body Weight Set-Points: Determination and Adjustment. The Journal of Nutrition, Volume 127, Issue 9, 1997, Pages 1875S-1883S, ISSN 0022-3166.

[2]KHOSLA T, BILLEWICZ WZ. MEASUREMENT OF CHANGE IN BODY-WEIGHT. Br J Nutr. 1964;18:227-39.

[3]Goodner CJ, Ogilvie JT. Homeostasis of body weight in a diabetes clinic population. Diabetes 1974 Apr;23(4):318-26.

[4] Gary Taubes. 2011. Why we get fat. New York: Anchor books, Page 59.

[5]Egan AM, Collins AL. Dynamic changes in energy expenditure in response to underfeeding: a review. Proc Nutr Soc. 2022 May;81(2):199-212. doi: 10.1017/S0029665121003669. Epub 2021 Oct 4. PMID: 35103583.

[6]Ganipisetti VM, Bollimunta P. Obesity and Set-Point Theory. 2023 Apr 25. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 37276312.

[7]Bray GA.The pain of weight gain: self-experimentation with overfeeding. Am J Clin Nutr. 2020 Jan 1;111(1):17-20.

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