1. Grass-Fed Beef Yeah, I know: grass-fed beef is a little pricey. But its higher ratio of good-for-you fats make it well worth the cost: A study in Nutrition Journal found that grass-fed meat contains higher levels of omega-3 fatty acids, which are known to reduce the risk of heart disease. And when it comes to your waistline, grass-fed beef is naturally leaner and has fewer calories than conventional meat. 2. Olive Oil Olive oil is rich in cancer-fighting polyphenols and heart-strengthening monounsaturated fats, and when it comes to looking lean, it's backed by some pretty strong facts. A recent study from Obesity found that an olive-oil-rich diet resulted in higher levels of adiponectin than did a high-carb or high-protein diet. 3. Coconut Coconut is high in saturated fat, but more than half of that comes from lauric acid, a unique lipid that battles bacteria and improves cholesterol scores. And get this: A study published in Lipids found that dietary supplementation of coconut oil actually reduced abdominal obesity. Of the participants, half were given two tablespoons of coconut oil daily and the other half were given soybean oil, and although both groups experienced overall weight loss, only the coconut oil consumers' waistlines shrunk. Sprinkle unsweetened flakes over yogurt or use coconut milk in a stir-fry to start whittling your waist. 4. Dark Chocolate Good news for your sweet tooth: Chocolate can help you flatten your belly. Dark chocolate, that is. But to truly take advantage, don't wait until dessert: A recent study found that when men ate 3.5 ounces of chocolate two hours before a meal, those who had dark chocolate took in 17 percent fewer calories than those that ate milk chocolate. The researchers believe that this is because dark chocolate contains pure cocoa butter, a source of digestion-slowing stearic acid. 5. Almond Butter Numerous studies have indicated that almonds can help you lose weight despite their high fat content. In fact, a study from the International Journal of Obesity and Related Metabolic Disorders compared two diets over the course of six months. One group followed a low-fat, calorie-restricted diet (18 percent fat) and the other followed a moderate-fat diet (39 percent fat) in which the extra fat was supplied by almonds. The latter group lost more weight than the low-fat dieters, despite the fact that both groups consumed the same amount of total calories.