"Magic" foods

There seems to me to be a major disorder of thought out there. People think that eating "special" foods will cure all their ills. It's not just the "eat grapefruit" diets, eat protein diets, etc. that I'm thinking of. It's the idea that the quantity doesn't matter. If I eat 90 calories of sugery crap, I'll get fatter than if I eat 100 calories of nutrious fruit. UNTRUE. Calories are calories.