Feeling full after a meal results in a complex signal to stop eating, called satiety. The satiating power of a food refers to the ability of that food to reduce feelings of hunger. The satiating power of a variety of common foods fed in 240 calorie portions was measured in human volunteers.? This study, which? we have referred to in the past few issues of CFFH, showed that foods with higher water content, more fiber and fewer calories per ounce were generally associated with feeling more satisfied. For example, a medium-sized 5-ounce baked potato reduces hunger more than an ounce of potato chips even though they both contain the same amount of calories. Choosing foods that fill you up on fewer calories allows you to control your weight without ?dieting? or chronic hunger.Water content has by far the greatest effect on the concentration of calories found in a food. But simply drinking more water with a meal and/or adding water to food are not the key to reducing how many calories you need to eat to feel full. Anyone who believes that a soda is preferable to hard candy for weight loss simply because the calorie density of the soda is much lower than that of the hard candy (190 versus 1700 calories per pound), is likely to be disappointed. Research in animals shows that they often increase their calorie intake when given sugar in water versus dry form. Clearly there is more to satiety than simply increasing water content.One reason sugar in water may be less satiating than hard candy, despite a lower concentration of calories, is that it takes much longer to consume the hard candy. Another example is that 240 calories of oranges (about 4 oranges) or cherry tomatoes (2 pounds) take longer to eat than a small bag of M&Ms or 1.5 ounces of peanuts, also 240 calories each. In addition to their lower calorie density, the oranges and tomatoes would also supply a lot more fiber, which is likely to enhance satiety as well. Dr. Jay?s law is that in general, foods that take longer to eat (and slow calorie intake) tend to provide more satiety.Natural whole foods like potatoes, oatmeal, whole-wheat pasta, brown rice, fruits, vegetables, and beans have a high satiating power. Prepared and refined foods like crackers, bagels, cookies and candy have less. Why? Whole foods have a much higher fiber content and they digest more slowly and less completely, resulting in more calories and fiber reaching the latter part of your small intestine. Research suggests that this results in a powerful satiety signal that keeps you from getting hungry.Do I have to give up all tasty foods to lose weight? No. Reducing calorie concentration while maintaining palatability is a challenge but not impossible. Not all high calorie-dense foods are palatable and not all low calorie-dense foods are unpalatable. For example, fresh ripe strawberries can be very palatable at only 137 calories per pound, whereas vegetable shortening at 4040 calories per pound is quite unpalatable.Your best bet for foods that are low in calories and high in palatability are lowfat versions of: soups, stews, chili, pasta dishes, rice dishes, stir frys, baked potatoes, fruits, steamed vegetables and salads with low-fat dressing. The creative use of spices, condiments, high intensity sweeteners (e.g. aspartame, sucralose) and fat substitutes (e.g. Nutrim and Oatrim) can all be used to make a lower calorie-dense diet more palatable without increasing its calorie density.Does tasty food cause you to overeat? No! Research in both animals and people clearly show that they don?t eat more calories simply because their food tastes better.The use of aspartame was demonstrated to help prevent overweight women from regaining lost weight over a 175-week period without any reported increase in hunger.? Other studies have demonstrated a significant drop in caloric intake when aspartame replaced sugar and other high calorie sweeteners. It appears that the calorie density of the diet is far more important in affecting satiety and food intake than the palatability of the diet.Bottom Line: Reducing the calorie density of the diet while maintaining a reasonable degree of palatability may prove to be the best strategy for losing body fat and keeping it off, especially when coupled with regular exercise. The easiest way to do this is to greatly increase your intake of fruits, vegetables, whole grains and beans. Omit or limit foods that have a high calorie density such as cookies, candy, donuts, baked goods, crackers, potato chips, whole dairy products, and fatty meats.Dr. Jay Kenney, PhD, RD, FACN, is the Nutrition Research Specialist for the Pritikin Longevity Centers. He is on the Board of Directors for the National Council Against Health Fraud. He is Board Certified as a specialist in Human Nutrition Sciences by the American Board of Nutrition.See the insert in this issue for Dr. Kenney?s full text article with references andquestionnaire for obtaining 2CPE hours for RDs or visit our website at www.foodandhealth.com for all of our self-study programs published in CFFH.