If you're having a hard time dropping unwanted pounds, you may want to consider other options, such as diet pills. While some of these over-the-counter pills contain the "best" ingredients at promoting weight loss, they don't produce dramatic results. Consultation with a doctor is recommended to discuss safety and effectiveness of these types of diet pills and also to learn about prescription diet pill options.
Many diet pills contain caffeine as a single ingredient or in the form of an herb such as guarana, yerba mate or kola nut. As a stimulant, caffeine increases metabolism, but generally not enough to create a significant weight loss, according to the Office of Dietary Supplements.
The caffeine-containing herbs may help with weight loss by delaying gastric emptying -- meaning they keep your stomach full longer -- according to a 2001 study published in the Journal of Human Nutrition and Dietetics. However, caffeine-containing diet pills cause mild but adverse effects, such as nervousness, or serious, such as swelling of the brain, and use of these type of pills is discouraged.
Green tea is also a source of caffeine, but that's not the only active ingredient believed to help with weight loss. The tea also contains catechins, which are phytochemicals that may increase metabolism. However, while green tea is a source of nutrients that help you burn calories, it doesn't help you lose much weight, according to a 2012 study published in The Cochrane Database of Systematic reviews. The researchers of this review study, which included a total of 14 studies and 1,562 participants, concluded that weight loss from green tea was so small it wasn't clinically important
Green Coffee Bean Extract
Green coffee beans, which are unroasted beans, are also a source of caffeine and contain high amounts of chlorogenic acid. This particular acid has been shown to help prevent the accumulation of fat in both mice and humans, according to the Office of Dietary Supplements. While it appears that green coffee bean extract is promising for weight loss, very few human studies without biased data exist, according to a 2011 review study published in Gastroenterology Research and Practice. To better assess how green coffee bean extract might help with weight loss, additional clinical research is necessary.
White Kidney Bean
White kidney beans are legumes native to Central and South America that prevent the breakdown and absorption of carbs and suppress appetite. In diet pills, the legume appears as Phaseolus vulgaris. When taken as part of a reduced-calorie diet, participants in a small study -- published in 2014 in Obesity -- lost 6 pounds over a 12-week period, compared to 2 pounds in the control group. However, a review study from 2011 published in the British Journal of Nutrition says much of the research on white kidney beans and weight loss are flawed, and recommends larger, more rigorous studies to figure out how well it works.
Conjugated Linoleic Acid
Conjugated linoleic acid, or CLA, is made from linoleic acid and occurs naturally in animal foods such as milk and beef. Scientists theorize that CLA helps promote weight loss by destroying fat cells. Supplementation with CLA appears to help promote weight loss in obese people, according to a 2012 study published in Nutrition. However, the researchers note that, even though the study subjects lost some weight, they still didn't lose much, suggesting CLA alone isn't a magic bullet for significant weight loss. Additionally, a review study on CLA and weight loss reports mixed results, and study authors expressed concern that it might increase triglyceride and LDL, or bad, cholesterol, while lowering HDL, or good, cholesterol. If you're worried about your cholesterol levels, that's a significant drawback.
Pyruvate is a chemical produced by your body during the production of glucose. It's also found in some diet pills, usually in the form of calcium pyruvate. Pyruvate might increase your fat-burning potential and metabolism, which could theoretically help you lose weight. While pyruvate does appear to help promote small amounts of weight loss, the current research is limited, according to a 2014 review study from Critical Reviews in Food Science and Nutrition. And like many of the ingredients found in diet pills, more research is needed to further evaluate weight-loss claims.
Chromium is an essential trace mineral that helps control your blood sugar levels, and fuels an active lifestyle by helping your cells access glucose, a fast and easy source of energy. It might help you increase your lean body mass and burn more. Chromium supplementation is linked to weight loss, according to a 2013 review study published in Obesity Review, which looked at the results from 11 prior studies. However, like other diet pills, chromium alone didn't trigger significant weight loss; it seems to offer a modest benefit at best.
- Office of Dietary Supplements: Dietary Supplements for Weight Loss
- Journal of Human Nutrition and Dietetics: Weight Loss and Delayed Gastric Emptying Following a South American Herbal Preparation in Overweight Patients
- The American Journal of Clinical Nutrition: Caffeine: A Double-blind, Placebo-Controlled Study of Its Thermogenic, Metabolic and Cardiovascular Effects in Healthy Volunteers
- International Journal of Sport Nutrition and Exercise Metabolism: Dietary Supplements for Improving Body Composition and Reducing Body Weight: Where Is the Evidence?
- Cochrane Database of Systematic Reviews: Green Tea for Weight Loss and Weight Maintenance in Overweight or Obese Adults
- Phytotherapy Research: Lipolytic Activity of Svetol, a Decaffeinated Green Coffee Bean Extract
- Gastroenterology Research and Practice: The Use of Green Coffee Extract as a Weight Loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials
- Obesity: Weight Reduction and Maintenance With Iqp-pv-101: A 12-Week Randomized Controlled Study With a 24-Week Open Label Period
- British Journal of Nutrition: The Efficacy of Phaseolus Vulgaris as a Weight-loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials
- Journal of the International Society of Sport Nutrition: A Review on Effects of Conjugated Linoleic Fatty Acid (CLA) Upon Body Composition and Energetic Metabolism