The type of food doesn't make you fat, its how much food you eat
. The reasons so many Americans are getting fat is because they're eating too much. The only reason we get so much bullshit about health thrown at us at all the time is because its a huge money maker. Its easier to make money selling books telling you what you should, how you should eat it and when you should eat it- then it is to simply say "just eat less"
The reasons certain diets work is because they make calorie deficit easier. Its easy to eat less calories on a low carb diet, its also easier to control how much you eat when you intermittent fast rather than eat 6 small meals a day. There's nothing special about these diets, they're just calorie control.
Clean eating is also bullshit, because there so many different interpretations to clean eating. Quite frankly, the only clean eating we need to take to heart is making sure the food doesn't fall on the floor.