If you are looking for dietary supplements that claim to help with weight loss, you may find hundreds of them on the market. Any of them are the “magic pills” for weight loss? A few reviews may tell you what scientists think after they have evaluated the literature on the effectiveness of dietary supplements for weight loss.

    Pittler and Ernst assessed the evidence from rigorous clinical trials, systematic reviews, and meta-analyses on the effectiveness of dietary supplements in reducing body weight. Data on the following dietary supplements were evaluated: chitosan, chromium picolinate, Ephedra sinica, Garcinia cambogia, glucomannan, guar gum, hydroxy-methyl butyrate, Plantago psyllium, pyruvate, yerba maté, and Yohimbe (1).

    These authors stated that the reviewed studies provided some encouraging data but no evidence beyond a reasonable doubt that any specific dietary supplement in that list was effective for reducing body weight. The only exceptions were E. sinica– and ephedrine-containing supplements, which had been associated with an increased risk of adverse events. They concluded that the evidence for most dietary supplements as aids in reducing body weight was not convincing. None of the reviewed dietary supplements could be recommended for over-the-counter use (1).

    Watanabe et al reviewed clinical studies up to March 2020. They categorized dietary supplements by their potential mechanisms of action, such as improvement of carbohydrate metabolism, increased lipolysis or energy expenditure, and reduced hunger. A recommendation for every food supplement was provided based on the quality of evidence, the strength of preclinical evidence, the clinical relevance, and the safety (2).

    Among evaluated food supplements with a primary impact on nutrients absorption: Green tea, Ginseng, White kidney bean, Chitosan, beta-Glucans, Psyllium, Glucomannan, Guar Gum, Agar, Inulin, the authors marked Green tea and White kidney bean as potentially recommended.

    Among evaluated food supplements with a primary impact on appetite regulation: Caralluma, Spirulina, Whey protein, Coffee (caffeine and chlorogenic acids), Bitter orange, Guarana, Whey protein and Coffee (caffeine and chlorogenic acids) were suggested as potentially recommended.

    Among evaluated food supplements with a primary impact on energy expenditure modulation: Capsaicin (capsaicinoids and capsinoids), Curcumin, and L-Carnitine, none of them was recommended.

    Among evaluated food supplements with a primary impact on fat metabolism: Pyruvate, Dyacilglycerol, Licorice, Garcinia Cambogia, Resveratrol, Conjugated linoleic acid, Aloe vera, Flaxseed, and Grapefruit, the authors potentially recommended Dyacilglycerol, Resveratrol, Conjugated linoleic acid, and Flaxseed.

    Among evaluated food supplements with a primary impact on carbohydrate metabolism: Mangosteen, Chromium, and Lipoic Acid, none was recommended.

    Interestingly, these authors came up with a combination of food supplements with various mechanisms of action as a potential combination formulation to promote weight loss (2).

    I wish these authors could have emphasized that whether this formulation could be potentially beneficial for weight loss would depend on when the fundamentals for energy balance were in the right direction, which is energy intake needs to be less than energy output. No matter which category the food supplements may fall into, the key actions would be either reducing the food intake (i.e. reducing the absorption or appetite) or increasing the energy utilization (metabolism or energy expenditure).

    Batsis et al. conducted a systematic literature review to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in adults. Of 20,504 publications, they reviewed 1,743 full-text articles, of which 315 were randomized controlled trials evaluating the efficacy of 14 purported dietary supplements, therapies, or a combination thereof. The authors found that the risk of bias and data sufficiency varied widely. Few studies (n=52 [16.5%]) were classified as low risk and sufficient to support efficacy. Of these, only 16 studies (31%) reported significant pre/post inter-group differences in weight (range: 0.3 to 4.93 kg). They concluded that dietary supplements and alternative therapies for weight loss had a limited high-quality evidence base of efficacy. Health professionals should be aware of the scientific evidence of dietary supplements before recommending use (3).

    The dietary supplements and alternative therapies that were evaluated for weight loss included: Acupuncture, Calcium-Vitamin D Supplementation, Chitosan, Chocolate/Cocoa, Chromium, Ephedra/Caffeine, Garcinia and/or Hydroxycitrate, Green Tea, Guar Gum, Conjugated Linoleic Acid (CLA), Mind-Body Therapy, Phaseolus, Phenylpropylamine, and Pyruvate (3).

    The authors stated that despite many citations evaluating dietary supplements and alternative therapies for weight loss, their review did not support strong, high-quality evidence of efficacy for any of the products. The authors specifically pointed out that studies should be free of potential commercial bias and their findings suggested this might not be the case. They emphasized the importance of well-designed, randomized, double-blinded controlled trials of sufficient duration to demonstrate the efficacy of any dietary supplements for weight loss (3).

    These few reviews on dietary supplements for weight loss may give you a sense of what scientific evidence are out there for the so-called weight loss dietary supplements on the market. When you read more of these scientific evaluations, you would realize that there are no “magic pills” for weight loss.

    Sustainable weight loss requires a combination of a healthy diet and regular exercise, actually a lifestyle change. While there may be dietary supplements available that may aid weight loss, they are not a replacement for a healthy lifestyle.

    As pointed out by the authors of these reviews, a vast amount of literature that was available for dietary supplements and weight loss was often of low quality since the supporting studies were typically conducted or sponsored by dietary supplement manufacturers if any. The dietary supplements that are labeled to help with weight loss may have limited or no high-quality scientific studies to support the claims.

    Obesity is mainly driven by energy imbalance such as eating too much high-fat and high-sugar-containing foods and lacking physical activity, and the excess fat accumulation can only be reduced when the energy in would be less than energy needed. If a dietary supplement can actually shut down a person’s appetite then this person can reduce energy intake by not eating. However, if that happens, then this dietary supplement would be well considered as a drug.

    It is crucial to keep dosage in consideration as it is acknowledged in many fields that dosing can make the difference between beneficial effects and toxicity, and too often commercially available supplements provide highly variable amounts without even properly acknowledging it on labels. Some weight loss supplements may even have potentially harmful side effects. In addition, no government agency is regulating these dietary supplements on the market.

    Rather than looking for an easy fix with “magic pills”, it may be best to focus on making sustainable changes to your lifestyle. This can include things like incorporating more healthy foods such as whole grains, which are B-vitamin-containing foods, and B vitamins are essential cofactors for energy metabolism, plus doing more physical activities. When you work towards weight loss goals, keep in mind the fundamentals for energy balance: when the energy in is less than energy out, then there is a chance of losing weight.

References:

1. Pittler MH, Ernst E. Dietary supplements for body-weight reduction: a systematic review. Am J Clin Nutr. 2004 Apr;79(4):529-36. doi: 10.1093/ajcn/79.4.529. PMID: 15051593.

2. Watanabe M, Risi R, Masi D, Caputi A, Balena A, Rossini G, Tuccinardi D, Mariani S, Basciani S, Manfrini S, Gnessi L, Lubrano C. Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review. Nutrients. 2020 Sep 20;12(9):2873. doi: 10.3390/nu12092873. PMID: 32962190; PMCID: PMC7551574.

3. Batsis JA, Apolzan JW, Bagley PJ, Blunt HB, Divan V, Gill S, Golden A, Gundumraj S, Heymsfield SB, Kahan S, Kopatsis K, Port A, Parks EP, Reilly CA, Rubino D, Saunders KH, Shean R, Tabaza L, Stanley A, Tchang BG, Gundumraj S, Kidambi S. A Systematic Review of Dietary Supplements and Alternative Therapies for Weight Loss. Obesity (Silver Spring). 2021 Jul;29(7):1102-1113. doi: 10.1002/oby.23110. PMID: 34159755; PMCID: PMC8231729.
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