Normal food is fine and if you eat too much and don't do enough exercise you will gain weight no matter what you eat. A balanced diet between healthy food and exercise is required which most of us stick to.
Where we all fall down is snacks between meal times. A bar of CHOCOLATE or a bag of CRISPS are things that we could do without but don't. The snacks are the killer and is our weakness. These are the diet killers that we can't resist.
If you see an overweight person 995 of the time they eat badly. What I mean is they may eat healthily but there are some snacks somewhere along the way. If I have snacks and I do I always do some extra exercising somewhere to make sure I don't gain weight.
My mum is a health freak and reads a lot, she was telling me not so long ago that the foods that make us overweight are man mad.
Anything that is fresh from a field and has never been in a factory and processed will keep us health and thin.
In some countries where they have no access to processed foods they live the healthiest lives, they have no cancer no obesity and there skin is healthy.
From the end of the world war people were healthy, they lived without processed food and lived healthy, once the war was over the government needed away to feed the country and fast and then processed foods came into play, feeding thousands of people with added ingredients that are known by the government to make us fat, unhealthy and in poor health.
Almost everything that starts with:
Unless perhaps you use them moderately.
I would call them snacks or junk food
Chocolate is the main one. Anything with sugar in it is not good for you and will cause you to gain weight fater then healthy foods.