Genetics > Food > Exercise in my experience.

Of course if you have good genetics, you do not eat more food than your body needs and with moderate 3 times a week exercise you can have a good looking body and good health.

Most people in real life however do not combine all three factors.

I know people will probably disagree with me but that is my view about it.

sorry for saying upfront, but one cant enjoy food, eat well and still be thin and healthy.

@Gerald

Genetics plays a huge factor.

I myself, have been skinny and lean all my life, no matter what, or how I eat. My high performing metabolism is genetically inherited - my dad, and his dad, are the same. Yes, I can eat a whole pizza for dinner. I can stuff myself full of chocolate whenever I want. My weight does not change, ever.

There's a theoretical model for body types, which states that there are 3 categories that we all fall into. There's the ectomorphs, who find it extremely hard to gain either fat or muscular mass. Then there's the endomorphs, the opposite of the ectomorphs, with a larger frame and easily accumulate adipose tissue and find it hard to shrug this off. And finally, the mesomorphs, which most of the general populace is said to be, which fit somewhere in between, and display characteristics from both.

In France, we are also taught that eating too fast isn't good, and that it increases the risk of obesity.

There are several causes: if you eat faster, you still feel hungry even though you've eaten enough food as it's takes some time (about 15-20 minutes I believe) for the stomach to "say" it has had enough.

Another thing is that with bread, pasta and rice, we aren't hungry for a while. It's the kind of ingredients that should be included in most lunches.

Finally, there would be habits, in France, we do give a lot of importance to meals, and it is rare to see adults snacking outside of those meals (kids do have an afternoon snack, and a morning one for the younger ones). (I exclude the snacks that some who have physically tiring jobs might take, as it is totally understandable)

Dear Parvaneh, one thing that is very important too is the time that we eat. You should never eat much before you go to sleep for example. And then especially no fast carbs like sugar. You will not use that energy, and that sugar in your blood will turn into fat. For example never have a big meal at say 22.00 hours, and then go to sleep an hour after that. That is deadly. Well, not deadly perhaps, but not very healthly at the least.