Despite how it might appear in their advertising campaigns, most weight-loss supplements do not work miracles. A few, however, provide a small advantage to people already eating well and exercising regularly. To help customers decide which supplements to try, you must first know how they work.

Now that ephedra's days on the market appear numbered (see news story on cover), the thermogenic properties of green tea (Camellia sinensis) are making it one of the most popular components in weight-loss supplements. Green tea's power comes from the combination of caffeine and the plant chemical epigallocatechin gallate. Together, these constituents boost nonadrenaline hormone levels, thereby increasing metabolism and the number of calories burned.

In a 1999 study published in the American Journal of Clinical Nutrition, healthy men were randomly given either a green tea supplement (containing 90 mg EGCG and 50 mg caffeine), 50 mg caffeine or placebo. The men then ate a normal diet and did not exercise. Results showed only those who took the green tea supplement experienced a significant increase in calorie burning.

What to recommend: Steer your clients to standardized green tea supplements that contain caffeine.

Chromium
Rather than increase calorie burning, the essential mineral chromium helps turn ingested calories into muscle instead of fat. Chromium works its magic by increasing the effectiveness of the hormone insulin. This in turn boosts glucose absorption into cells, where it is used as energy, rather than stored as fat. In his book Anti-Fat Nutrients (Pax Publishing, 1997), Dallas Clouatre, Ph.D., suggests as many as 90 percent of Americans are at least marginally deficient in chromium. Therefore, supplementation with this mineral might give your clientele the extra edge they need to lose a few pounds.

What to recommend: Suggest customers try chromium in the easily absorbed picolinate form.

L-Carnitine
The amino acid L-carnitine, produced in small amounts by the body, transports fatty acids across cell membranes into the mitochondria where they are burned for energy. This nutrient also helps remove waste products from cells and helps rid the liver of stored fat.

Although results of clinical studies examining L-carnitine supplementation's effect on fat metabolism are mixed, there is no doubt a deficiency in this amino acid is linked to fatigue, elevated lipids and muscle weakness. Individuals with certain types of obesity may have a genetic tendency to produce less carnitine. Supplementing with the amino acid may help people burn fat and feel more energetic.

What to recommend: Advise customers to take L-carnitine in capsule form, on an empty stomach.

Conjugated Linoleic Acid
It won't necessarily burn more fat, but conjugated linoleic acid may keep pre-existing fat cells from getting any larger. This nonessential fatty acid found in meat and dairy products was shown to exert anticancer effects as well as increase fat loss during dieting. In a study published in the Journal of Nutrition (2000) overweight and obese individuals who did not change their diets or exercise habits, but took 3.4 g to 6.8 g of CLA daily for 12 weeks, had a slight reduction in fat mass.

What to recommend: CLA is sold in capsule form to be taken in divided doses.

Flavonoids
Besides being packed with antioxidants and fiber, fruit and vegetable pigments known as flavonoids may also help people lose weight, water and maybe even cellulite. For example, studies show Pycnogenol—a branded flavonoid found in pine bark and other plants—stimulates fat burning and may prevent fat deposits by inhibiting a fat-producing enzyme (Phytotherapy Research, 2000). Flavonoids extracted from grape seeds and bilberry fruit were also shown to reduce fluid retention.

What to recommend: Customers should follow the dosage information on flavonoid supplements.

FiberOne of the biggest dieting hurdles is feeling full with fewer calories. Boosting fiber intake can help customers feel satiated. The soluble, semi-soluble and insoluble fiber found in fruits, vegetables, legumes and whole grains can also help shuttle fat out of the body. Fiber supplements, such as those made from psyllium husk, may also help people eat less and still feel full.

What to recommend: Good fiber products are sold in capsule and powder forms and should be taken with lots of water.

Protein
Studies show eating more protein can also help people consume fewer calories. In a six-month trial published in the International Journal of Obesity (1999), researchers put 65 obese people on one of two diets: a diet with 12 percent of total calories coming from protein, or a diet with 25 percent of calories coming from protein. Although none of the subjects exercised, those who ate more protein lost more weight.

What to recommend: Suggest protein powders and bars low in sugar and fat.

When discussing weight loss products with your customers, be sure to first recommend they eat well, exercise and drink lots of water. In addition, a visit to their health practitioners is a wise idea before starting any new supplement regimen.

Linda Knittel is a Portland, Ore.-based freelance writer who specializes in nutrition, fitness and women's health.