Obesity

What about herbal fen/phen?

Since the withdrawal of fen/phen from the market, "herbal fen/phen" has been proposed as an alternative in treating obesity. But the U.S. Food and Drug Administration has issued a warning that "herbal fen/phen" has not been shown to be a safe and effective treatment for obesity and may contain ingredients that have been associated with injuries.

The main ingredients in most herbal fen/phen products are ephedrine and St. John's wort. Ephedrine acts like amphetamines in stimulating the central nervous system and the heart. Ephedrine promotes weight loss in part by an increase the body's temperature, and when this happens, the body burns more calories. Ephedrine use has been associated with high blood pressure, heart-rhythm irregularities, strokes, insomnia, seizures tremors, and nervousness. There have been reports of deaths in young individuals taking ephedrine. St. John's wort has been used in Europe to treat mild depression but not obesity. The action, effectiveness, and side effects of St. John's wort either alone or in combination with other agents have not been adequately studied.

What about meal substitutes, artificial sweeteners, and over-the-counter (OTC) products?

Meal substitutes

When used as substitutes for regular meals, meal substitutes are a convenient way to reduce calories as part of a low-calorie diet plan. A typical meal substitute available in powder and liquid form is Slim-Fast. Ensure is another meal substitute available in both liquid and bars. Meal substitutes should provide protein and be low in fat and calories. The label should include the amount of calories per serving and the percentages of protein, carbohydrates, and fat. The total number of calories per serving is predetermined so it is easier to keep track of the daily consumption of calories. As with all dramatic changes in your diet, you should consult your health-care provider to make sure that these changes will not have negative consequences.

Artificial sweeteners

Saccharin (Sweet'N Low) and aspartame (Equal) are sugar substitutes that provide little or no calories. They may be used as a substitute for table sugar. Using saccharin instead of a teaspoonful of sugar eliminates 33 calories from the diet. People with phenylketonuria (a serious genetic disease in which an individual is unable to break down and eliminate an amino acid, phenylalanine) should not use aspartame because it contains phenylalanine.

Fructose, sorbitol, and xylitol may be used as alternatives to sugar, but they provide more calories than saccharin and aspartame. Excessive use of sorbitol also may cause diarrhea.

OTC weight-loss products

Despite claims by manufacturers, the use of OTC products alone does not cause weight loss. Herbal weight-loss products or preparations called "fat burners" are even more misleading. These products may contain a combination of ma huang (a botanical source of ephedrine), white willow (a source of salicin), Hoodia gordonii, and/or guarana or kola nut (a source of caffeine). These agents are stimulants, which theoretically increase the metabolism and help the body break down fat. Nevertheless, there is no evidence that they are effective for weight loss. In addition, ma huang has been linked to serious side effects such as heart attacks, seizures, and death. Chromium also is a popular ingredient in weight-loss products, but there is no evidence that chromium has any effect on weight loss.

Weight-loss teas contain strong botanical laxatives (Senna, cascara sagrada) and diuretics (Rhamnus purshiana) that cause diarrhea and loss of water from the body. Diarrhea and water loss lead to the depletion of sodium and potassium and can lead to dehydration. Although an individual's weight may decrease, the loss is due to a decrease in fluid and is only temporary. Moreover, low sodium and potassium levels may cause abnormal heart rhythms and can even lead to death.

Guar gum preparations have also been promoted as a weight-loss agent. Guar gum is thought to work by leading to a feeling of fullness early in the meal. It has not been scientifically proven and has been associated with abdominal pain, gas, and diarrhea.

All of the OTC products discussed above are not considered drugs and are therefore not regulated by the Food and Drug Administration. As a result, there is little information on their effectiveness or safety. You should discuss any OTC weight loss products you are planning on taking or are taking with a health-care professional.

REFERENCES:

National Institutes of Health (NIH); "Classification of Overweight and Obesity by BMI, Waist Circumference, and Associated Disease Risks." "Body Mass Index Table."

Manson JE, Colditz GA, Stampfer MJ, Willett WC, Rosner B, Monson RR, Speizer FE, Hennekens CH.; "A prospective study of obesity and risk of coronary heart disease in women." N Engl J Med. 1990 Mar 29;322(13):882-9.

W. B. Droyvold, T. I. Lund Nilsen, S. Lydersen, K. Midthjel, P. M. Nilsson, J. Nilsson, J. Holmen; "Weight change and mortality: the Nord-Trondelag Health Study." Journal of Internal Medicine. Volume 257 Issue 4, Pages 338 - 345

National Center for Health Statistics; "National Health and Nutrition Examination Survey." http://www.cdc.gov/nchs/nhanes.htm.

World Health Organization; "Global Database on Body Mass Index."

Life Measurements, Inc. (www.bodpod.com)

United States National Library of Medicine, National Institutes of Health; "Bioelectric Impedance Analysis in Body Composition Measurement."

Lars Sjöström, M.D., Ph.D., Anna-Karin Lindroos, Ph.D., Markku Peltonen, Ph.D., Jarl Torgerson, M.D., Ph.D., Claude Bouchard, Ph.D., Björn Carlsson, M.D., Ph.D., Sven Dahlgren, M.D., Ph.D., Bo Larsson, M.D., Ph.D., Kristina Narbro, Ph.D., Carl David Sjöström, M.D., Ph.D., Marianne Sullivan, Ph.D., Hans Wedel, Ph.D.. "Lifestyle, Diabetes, and Cardiovascular Risk Factors 10 Years after Bariatric Surgery." New England Journal of Medicine. Volume 351:2683-2693, December 23, 2004.

U.S.  Department of Health and Human Services, U.S. Department of Agriculture; "Dietary Guidelines for Americans."

Medically Reviewed by a Doctor on 12/9/2015