How the number of meals affects obesity?


  1. The relationship between the number of meals and weight gain
  2. How many meals a day makes you fat the most?
  3. Can eating more often help you lose weight?
  4. Cause and effect are sometimes reversed


(1) If you take into account the fact that “the phrase ‘to gain weight’ has two meanings”, there are several possible patterns.
[related article]→ 2 meanings to the phrase "gaining weight"

(2) One or two meals a day tend to make you gain weight in the long term, but the number of meals alone does not decide if you will gain weight. The most important thing is "what to eat” and other factors can also influence.

(3) Increasing the number of meals may help you lose weight.

(4) Studies that only examine the relationship between the number of meals and obesity are useless. A reverse causality may arise when people are already big or overweight and thus eat four to five meals a day.

1. The relationship between the number of meals and weight gain is not so simple

Some experts say that if the total calorie you take in a day is the same, then "how many meals you eat a day does not matter," but I definitely insist that the number and timing of your meals can affect your weight gain (or loss). 

I mentioned that the phrase "to gain weight" has two meanings, so let me explain part (A) first.

Many people think that “taking in more calories makes you gain weight”, which means going back to their Base Weight(BW).

In this case, it’s nothing to do with “how many meals you eat a day".
But people who usually be on a diet and keep their weight lower, or who endure hunger in a long time, may gain weight if they eat more calories than they need.

As for part (B), the opposite is true: Since it is the mechanism of hunger (strictly speaking, intestinal starvation) that increases the BW itself, eating more often and taking in more calories do not mean increasing the BW.
Rather, taking in the same calories by eating more often is less likely to lead to weight gain. When you feel hungry, foods enter your stomach again, which means that undigested foods are more likely to remain in your stomach and intestines. 

Therefore, eating four or five times a day for thin people to gain weight is counterproductive.
Also, for people who want to lose weight, skipping breakfast or lunch in order to reduce calories intake and eating only two meals a day while putting up with hunger can easily increase their BW in the long run. Thus, it may lead to the opposite result.

2. How many meals a day makes you fat the most?

Based on my idea, people tend to gain weight (that means their BW increases) if they skip breakfast or lunch and eat only two meals a day. However, eating two meals a day does not necessarily make everyone overweight. And conversely, even if you eat four or five meals a day, you will not always lose weight. 

It is pointless to argue that only in terms of “how many meals a day you eat”. If I explain this relationship from the perspective of the intestinal starvation mechanism, “how many meals you eat a day” actually means "meal intervals", and that is not the deciding factor for gaining weight. The most important thing is "what to eat (quality and balance of foods)”.


(three balanced meals a day ↑↑)

(three unbalanced meals a day ↑↑)

Others that may affect are "timing of eating (e.g., is lunch at 12 pm or 2 pm?)" and a person's "digestive power". This mean that, even if they eat exactly the same foods in the same way, people who can digest them faster make the state of intestinal starvation faster.

[related article]→ What does it mean to eat relatively less?

■A friend of mine who gained weight only with one meal a day

A friend of mine in college worked part-time in a restaurant. He ate only the meal for employee there and nothing else, so he had one meal a day.

(His meals there were often a bowl of rice and a few side dishes, miso soup, etc.)

He gained about 10 kilograms since he started working. He once could not gain weight even though he was eating three meals a day and more calories, in high school (i.e. this is not a calorie issue).

■A friend of mine who gained weight by eating four to five meals a day

Another friend of mine gained more than 10 kilograms by eating four to five meals a day when he was studying for a college entrance exam after graduating from high school. He belonged to a judo(Japan’s national sport) club in high school, and was very thin even though he ate a lot. 

But please note that it is not the five meals a day that make you fat, but what you eat (quality and balance of foods) and how you eat that matter. He told me that light meals such as sweet bread, rice balls, and cup noodles made up more than half of his meals.

If even a light meal such as a pastry, hamburger, or rice ball counts as "one meal", how many meals you eat a day does not account for the result.

3. Can eating more often help you lose weight?

Although what you eat is the most important thing, and I cannot make an assertion only based on the number of meals, I believe that increasing the number of meals a day is one right way to lose weight soundly.

According to a study by Professor Imai and her group at Osaka University (2016), there was a change in blood sugar levels in diabetic patients depending on what time of day they ate cookies.

The results of the experiment showed that eating cookies between meals kept the peak blood sugar levels lower than eating them just after a meal.

This is an experiment with a snack, but you can change cookies with a bit heavier diet, like cheese, fried mushrooms in oil, or even sautéed meat.

Please don’t get me wrong. I am not saying that it helps you lose weight because it is less likely to raise your blood sugar levels.

Rather than enduring hunger for a long time and eating with a bang, snacking throughout a day in order not to create hunger leaves more "undigested" food in your intestines and reduces “absorption rate” first, which results in less blood sugar levels.  I believe reducing “absorption rate” is more crucial in regard to losing weight.

4. Cause and effect are sometimes reversed

In some cases, studies only about “the number of meals” may tell a lie.
For example, suppose you surveyed overweight and obese people and asked them how many meals a day they eat. Let's assume that most of them answered four to five times. But you cannot take the overall results and say “eating four or five times a day is likely to make you gain weight”. 

The reason for this, as I said earlier, is that the most important things are missing: what you eat, how you eat, and how much you eat, etc. Additionally, as your body gets bigger, your stomach and intestines also become bigger and have more digestive power, so it is natural that you feel hungry faster even if you eat the same amount as others.

In other words, it is not because you eat more often that you gain weight, but because you have a bigger body, and thus you may end up eating more frequently than others as you cannot put up with hunger. Therefore, in this case, the cause and effect are the opposite.