Eat more fiber! Research at Tufts University found that whole grains, like wheat, brown rice, and oatmeal, contain about double the fiber as processed foods, like white rice, white bread, and crackers. The researchers also found people who get plenty of fiber consume fewer calories overall. People who eat lots of fiber also have a faster metabolism. Bottom line: Replacing processed grains in your diet with whole grains, and adding more fiber from produce, can help you lose weight and keep it off just as effectively as a brisk 30-minute walk every day.