Why people believe "low fat and high carbohydrate diet" can help us not getting overweight?

Provided you eat healthy carbs and not simple, processed carbs, you can lose weight on high carb low fat diets. High carbs gets your metabolism working as long as you eat high volume, low carb foods in large volumes(like raw veges). Durianrider on youtube eats up to 70 bananas a day and has 3% bodyfat. And there is 100 calories in one banana, so whoever says high carbs make you fat isnt eating properly. Loads of fruit and veges, lots of water and some exercise and you will be lean as a bean in a month or two.

Carbs are what make you FAT.

What you need to do is have no more than 20 carbs a day for a few months. Without all the extra carbs your cells do not save fat. You can eat fat and calories and they are not stored by your cells.