The US Food and Drug Administration (FDA) has sent warning letters to 16 dietary supplement distributors making false and misleading claims for weight loss products promoted over the internet.

"Obesity in America is at epidemic proportions, and we will not tolerate companies making false claims promising easy fixes," Health and Human Services Secretary Tommy G. Thompson said. "There is no substitute for eating well and remaining physically active."

Many of these products claim to block starch, carbohydrates and fat calories, while allowing consumers to lose weight without any changes in lifestyle. For example, some of the product labels have claimed:

"Eat All You Want! Block the Starch and Lose Weight!"; "Neutralize up to 66 per cent of the starch consumed in a meal"; "This advanced dietary-fat inhibitor helps block the absorption of fat calories"; "Take 3 capsules before bedtime. Watch the fat disappear!"; and "Guaranteed to block the breakdown of carbohydrates and simple sugars from being converted into fat."

"These products give unfounded hope to people who are attempting to lose weight. False and misleading claims have significant health consequences to individuals that may be overweight because these products do not produce the desired results," said Acting FDA Commissioner Lester M Crawford, DVM, Ph D. "FDA will continue to enforce the law and pursue products that lure consumers with unsubstantiated weight loss claims."

Although dietary supplement labeling may include claims about the supplement's effect on the structure or function of the human body, the law requires that "structure/function" claims must have substantiation and be truthful and not misleading. After reviewing the claims of the various products, FDA concluded that claims being made regarding these products are not supported by reliable scientific evidence.

FDA is requesting a response from the firms in writing within 15 days of receipt of the warning letters stating the action the firms will take to correct the noted violations and to ensure that similar violations do not occur in the future.