Well, I would argue that eating less calories definitely help. But sugar doesn't stop the hunger, and you need a certain amount of vitamin, protein, and fibers as well. My mom calls food with just sugar 'empty calories', a term that covers the load pretty well, I think.

I find that fat, proteins, and carbs help me to feel full. I can eat four donuts and still feel like I barely ate something. But one egg and I'm good to go for another hour.