- Some of the ingredients in these pills--such as guar gum and chitosan--can cause side effects like diarrhea, vomiting, flatulence (gas), bloating and other problems as they prevent your body from absorbing certain nutrients, which in turn increases the loss of other nutrients.
- Some diet pills can cause heart palpitations or arrhythmias, and even heart attacks, stroke or death. Some can also cause seizures, insomnia and/or hypertension (high blood pressure). Avoid diet pills containing ephedra (which has been banned, but is available online), country mallow and bitter orange (and other "ephedra substitutes").
- The diet pill industry is largely unregulated by the FDA, and many weight loss claims are mostly unsubstantiated by solid long-term evidence. Look for packaging that has an FDA disclaimer. Among the "doesn't work" or "little evidence" drugs and herbs are hoodia, chromium and green tea extract.
- Even seemingly innocuous products contain some of these herbs and supplements. Some multivitamins claim to help with weight loss, as do some "enhanced water" drinks and other products sold in stores. Read the labels and check the ingredients to know what you are consuming.
- The long-term effects of some diet drugs and herbs is unknown, while others (like ephedra) are known to be dangerous. There is little evidence to support their weight loss claims, but there is growing evidence on the side effects and the dangers of using some of them.
