This is because some people drink too much water in the hope of killing their appetite. They say that half a bucket a day.
It has long been an idea to replace extra snacks with a glass of water. This is because sometimes people confuse thirst and hunger. That is, they want something, and they start eating. They were just thirsty, though. Therefore, it is best to start with a glass of water. Maybe you don't want anything else.
There is also an opinion that a glass of water will fill the stomach, and nothing else will fit there. That is, it is better to eat water without calories than anything with calories.
Modern nutritional guides call plain water the best drink to drink with lunch.
We will not recall any separate nutrition and dilution of gastric juice with water, because this is nonsense. Better to remember the idea of a bag with a hole.
We are with you already discussed the saturation mechanism in people who are overweight and in people of normal weight.
After eating, our intestines release hormones that prevent the stomach from emptying. At the same time, food does not come out of the stomach, and excess calories are not absorbed.
In overweight people, the intestines go crazy from the abundance of refined food, forgets about hormones and about the stomach. As a result, the stomach empties continuously. And in the direction of the intestines. From this, more and more portions of food enter the intestines. Vicious circle. Obesity.
The trick is that in people of normal weight, the stomach does not just slow down its emptying. He also relaxes. From this, a person can stuff an additional portion of food into himself after eating. This is fine. But it would be better if instead of food he stuffed just a glass of water inside himself. It has no calories.
Something like that...