Simple formula for losing weight: Eat foods with higher fiber content. They require more chewing and take longer to digest, both of which reduce appetite. The average American eats 15 grams of fiber a day. Women need (on average) 25 grams and men 38 grams. (Apparently there are age dependencies for fiber intake. And another guideline recommends 14 grams of fiber for every 1,000 calories eaten (and also advises against eating too much fiber).