- One is by helping the body to break down body fat. This involves releasing it from fat cells, where it enters the bloodstream as free fatty acids that are then transported to muscle cells where they may be burned.
- The second action of weight loss supplements is to suppress appetite, which is a complex process. Many hormones and neurotransmitters are involved. We don't have all the answers in this area, but research continues. The human body's instinct is to survive, and once appetite suppressants are stopped, people become hungry.
- The third way weight loss supplements may work is by inhibiting the body from absorbing fat during digestion. Fat blockers don't work if a person isn't eating fat in his or her diet. They also won't prevent weight gain if a person is overeating protein or carbohydrates. The negative side effects of these supplements include stomach discomfort, diarrhea, and inability to absorb many important fat-soluble vitamins and other nutrients. In addition, they may interfere with the effectiveness of certain medications, especially birth control pills and estrogen.
Often, weight loss supplements contain more than one substance to generate weight loss from more than one angle. The ingredients are available alone, or with other substances. The following is a partial listing of some of the weight loss supplements you may see:
Promoted as a fat burner, carnitine naturally occurs in the body, and people can obtain it through eating meat, fish, poultry, and some dairy foods. Carnitine helps transport fatty acids to the muscle. In theory, it makes sense that more of it would help people get more fatty acids into the muscles, burning additional fat. Unfortunately, it doesn't live up to expectations, because taking its supplemental form doesn't result in increased fat burning.
Although this mineral helps metabolize carbohydrates and fats, it has not lived up to claims of increasing lean body mass and decreasing fat. As a matter of fact, the majority of the research done on this supplement shows it is not effective as a weight loss supplement. Some research showed damage to DNA with excess chromium picolinate that is exacerbated with Vitamin C. Taking in more than the body requires can actually reduce the binding capacity of iron in the blood, potentially resulting in iron deficiency and decreased ability to carry oxygen in the blood. This could negatively impact one's ability to exercise and expend calories.
This is probably the most popular substance in fat-burners on the market today. It acts like a hormone the body makes — norepinephrine. The action of this substance is associated with increased fat release from adipose (or fat) tissue, increasing free fatty acids in the bloodstream. Also increased are heart rate, heart contractility, body heat production, and metabolic rate. Ephedrine may also be able to suppress hunger. Studies have demonstrated that dieters were able to lose slightly more weight when taking ephedrine vs. placebos — but not nearly the amounts referenced in TV and magazine ads. It has been shown that ephedrine is even more effective when combined with caffeine — but so are the side effects, including tremors, dizziness, insomnia, heart arrhythmias, headaches, and increased blood pressure.
The U.S. Food and Drug Administration (FDA) has reported numerous adverse incidents and a number of deaths from taking supplements containing ephedrine or its precursors, ephedra or ma huang. Anyone with high blood pressure, heart disease, or diabetes, and pregnant women need to avoid this supplement. The National Football League (NFL) has listed it as a banned substance, and Canada prohibits its sale. Although ephedrine may help some people lose an extra few pounds, it doesn't seem worth the risk.
When a supplement touts "proven in clinical trials," you need to dig deeper. If the manufacturers are citing animal studies, it may have no merit in terms of human outcomes. For one reason, fat metabolism in rats is different than in people. Often, preliminary research is done on these animals, but the same results often don't pan out in humans. We are learning that fat burning and some hormonal responses are not the same between the two species. Some supplement manufacturers jump the gun before substances can be proven in humans, often in the name of big bucks. Another caveat is that when research is done, sometimes amounts of the ingredients or the ingredients themselves that the scientists use are not available to the public. Scientists may use substances in large amounts when studying them — not what is generally available at your local health food store. The supplement you find may contain additional components that alter the effect of the main ingredient. In addition, there is no guarantee that the supplement you buy has exactly what the label indicates.
Once again, there is really no safe short cut or quick fix to losing weight, no matter how slick the ads! And fat burners, despite the hype, do not work as advertised.