FEEL FULL ON FEWER CALORIES
By Barbara J. Rolls, Ph.D. and Tanja V.E. Kral, Nutrition Department, The Pennsylvania State University


Athletes wanting to lose body fat or maintain a low body weight often need to reduce their calorie intake. In the best of all worlds, these athletes want to consume a lower calorie diet but not feel hungry all the time; is that possible?

Research shows different foods and nutrients affect how full and satisfied people feel. For example, a number of studies indicate that calorie-for-calorie, protein makes a person feel more full than carbohydrates or fat. This suggests that eating adequate lean protein can help control hunger and food intake. Additionally, dietary fiber has been shown to affect satiety (that full feeling associated with eating) and food intake.

Research shows that eating an additional 14 grams of fiber per day is associated with a 10 percent decrease in calorie intake and a loss of body weight of about four pounds in four months. Eating more high-fiber foods such as fruits, vegetables and whole grains is a nutritionally sound way to not feel as hungry when reducing calorie intake. (Note: Athletes wishing to increase fiber should do so gradually to avoid stomach upset, gas and diarrhea.)

In addition to nutrients such as protein and fiber, the energy content of food, gram for gram, also affects how full it makes a person feel. The term for this is energy density , which is simply the amount of calories in a gram of food.

The relationship between the weight of food and its calorie content is largely affected by the amount of water in the food. Water adds weight but not calories, so the higher the water content the lower the energy density.

Studies consistently show that over the course of a day or two, a person eats about the same weight of food. On average, the weight of food eaten is more constant than an individual’s daily calorie intake. Thus, if a person eats the same amount (i.e. weight) of food, but lowers the calories in each portion, he/she will consume fewer calories. Studies also indicate that the calories won’t be missed, the individual will feel just as full.

Some tips for lowering a diet’s energy density include:

Increase intake of water-rich fruits, vegetables, and soups

Increase consumption of dietary fiber

Limit intake of dry foods Choose beverages wisely

Practical advice on how to apply the science of satiety and lower the energy density of a diet is in several consumer books recently published (see references six and seven). We expect energy density to be “the next big thing” in weight management because it is based on science and is a healthy way of eating. Athletes wishing to reduce calorie intake may benefit from this new science.

References

1. Doucet, E., Tremblay, A. Food intake, energy balance and body weight control. Eur J Clin Nutr 1997;51:846-55.

2. Howarth, N.C., Saltzman, E., Roberts, S.B. Dietary fiber and weight regulation. Nutr Rev 2001;59:129-39.

3. Rolls, B.J., Bell, E.A. Dietary approaches to the treatment of obesity. In: Jensen, M.D., ed. Medical Clinics of North America, Volume 84, March 2000. Philadelphia: W.B. Saunders Company, 2000: 401-18.

4. Poppitt, S.D., Prentice, A.M. Energy density and its role in the control of food intake: evidence from metabolic and community studies. Appetite 1996; 26:153-74.

5. Stubbs, R.J., Ritz, P., Coward, W.A., Prentice, A.M. Covert manipulation of the ratio of dietary fat to carbohydrate and energy density: effect on food intake and energy balance in free-living men eating ad libitum. Am J Clin Nutr 1995; 62:330-7.

6. Rolls, B., Barnett, R.A. The Volumetrics Weight-Control Plan: Feel Full on Fewer Calories. New York, NY: Quill, HarperCollins Publishers, 2000.

7. Hensrud, D.D., editor. Mayo Clinic on Healthy Weight. Rochester, MN: Mayo Foundation For Medical Education and Research, 2000.