Medical theories that are not true. There are many but let’s start with obesity. The theory is eating less and exercises more and you will lose weight. It might have worked in Auschwitz where people did not have food. This sounds very simplistic and if true everyone would be thin. There is something going on here that they ignore that is the cravings for food people have. Let’s look at what would cause cravings there is an illness called pica it normally is referred to people and animals that eat things that are not considered food like [light bulbs, paint, paper, dirt, wood, or horses eating guard rails]. This is well documented as being caused by a mineral deficiency usually by two or three minerals but it is not that simple because the interaction of minerals is like a dance you need one to absorb another or one might prevent you from absorption. It is a proven fact that when a vegetarian sees a horse eating a guard rails he will tell the farmer to give the horse a salt block which is not all salt but a mixture of many minerals. When people get all the minerals their craving goes away and they lose weight. It would not matter if you had a craving for light bulbs or potato chips the illness is the same. I can give you other failed medical theories if you like.
Eating less and exercising more will make you lose weight. That's a fact. Your speech about cravings might explain why some people have trouble eating less but does nothing to change the fact. Eating the right foods is important for good health but, even with no change in what you are eating, eating less will help you lose weight.
You are right, if you can eat less you will lose weight but, if it was so simple, why are so many people over weight? Like I said, in Auschwitz nobody was overweight. With the availability of food and the cravings for it, that is why.
Like you said, it's hard to overcome the cravings and therefore hard to have the discipline to eat less. Another factor is exercise. As we get older exercise becomes more difficult. With limited ability to exercise, eating less and eating right becomes more important.
One of the problems is eating right in 1980 there was a 15% obesity rate in the US in 1980 the USDA Dietary Guidelines for Americans came out and now the population is 35% or more obese. These are the people who say what is good to eat???
When I first visited Thailand in 1987, it was rare to see an obese Thai. At that time, about the only fast food joint was Dunkin Donuts. Now, 28 years later, there are many obese and of course, there is just about every fast food place available. In the jungle and small villages, people are still fit!
There is next to no nutrition value in fast foods so your body craves more looking for certain minerals.
There is actually a theory that depriving the body of food can actually cause it to gain weight instead of losing it. I don't know if this is actually true, but it does make some sense. It seems that with diet systems that don't deprive people that these seem to have the higher success rate. You know the ones you see them advertised on TV all the time, these plans maybe expensive but they get results because the plans are about teaching different eating habits not depriving people.