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Study Shows Weak Effectiveness for Weight Loss Supplements

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Key Takeaways:

  • Supplements for weight loss are readily available in stores and online, but are not heavily regulated or tested for effectiveness by government authorities.
  • A new systematic review evaluated the effectiveness of weight loss supplements for adults.
  • The review shows that there isn’t strong, high-quality evidence of the efficacy of any of the weight loss products.

More than two-thirds of American adults are overweight or obese, and many consumers turn to dietary supplements that promise to help with weight control. A recent systematic review published in Obesity took a closer look at the effectiveness of these weight loss products.

Many weight loss strategies have a bad reputation for leading to failure. Even FDA-approved weight loss medications and bariatric surgeries only promote modest weight loss results.

When struggling with options for weight control, many consumers turn to dietary supplements and alternative therapies that are marketed for fast, effective weight loss. These supplements provide hopeful promises that they will be a winning solution. Usually, this is not the case for weight loss or maintenance.

About 34% of adults report using dietary supplements to aid in weight loss. In fact, of the 776 dietary supplements identified in the FDA drug database, about 40% are marketed for weight loss. Many are endorsed by celebrity influencers, who are trusted by consumers.

Unfortunately, consumers don’t know that these dietary supplements aren’t tested or thoroughly evaluated for safety and efficacy by the FDA, and most aren't effective.

What Was Studied?

In this systematic review, researchers looked at 20,504 total citations, reviewed 1,743 full-text articles, and included 315 in the full-text review. They specifically looked for studies on dietary supplements and alternative therapies for weight loss, to search for evidence on the efficacy of these products.

Studies on 14 different dietary supplements and alternative therapies for weight loss were included in the review, including:

What Did the Study Find?

There were plenty of studies evaluating dietary supplements for weight loss, but the review shows that there isn’t strong, high-quality evidence of the efficacy of any of the products.

“Our extensive review of the literature suggested that despite a wide range of supplements and dietary alternatives that are available and marketed to promote weight loss, there is a lack of formal, high-quality, methodologically sound clinical trials to support the evidence in clinical practice,” says John A. Batsis, MD, an associate professor at the University of North Carolina at Chapel Hill and one of the study’s authors.

This review found that many of the published studies have small sample sizes, short study follow-up, don’t consider ethnicity or age of cohorts, have poor study design, and are affected by commercial bias, which often leads to inconsistent conclusions.

“I am not surprised by this result,” says Beth Conlon, PhD, MS, RDN, a dietitian and biomedical scientist with clinical and academic research experience in weight management.

John A. Batsis, MD

Our extensive review of the literature suggested that despite a wide range of supplements and dietary alternatives that are available and marketed to promote weight loss, there is a lack of formal, high-quality, methodologically sound clinical trials to support the evidence in clinical practice.

— John A. Batsis, MD

“It is important to differentiate between how researchers interpret low-quality evidence and how the general public may misinterpret it," says Conlon.

In the case of this new systematic review, Conlon says she was surprised to see that there were so few high-quality studies available, given the enormity of the weight loss supplement industry.

“I agree with their conclusions that practitioners need to consider the research limitations if recommending weight loss supplements to patients,” says Conlon. 

A Better Method for Weight Loss

For those seeking weight loss, the first-line treatment should be through lifestyle changes, like nutrition and physical activity, explains Conlon.

She adds that a better approach than weight loss supplements is to find and follow evidence-based information, to educate oneself on weight loss, and to seek the help of professionals for support and greater sustainability in making lifestyle changes as needed.

“The physician plays an important role in creating a weight loss support team that includes both a registered dietitian nutritionist and mental health professional for greater efficacy,” says Conlon.

But it is vital to find health care professionals without weight bias, which is a negative attitude toward someone based on their size. Look for professionals trained in intuitive eating, who will help you focus on an overall healthy relationship with food.

Beth Conlon, PhD, MS, RDN

For those seeking weight loss, the first-line treatment should be lifestyle changes, like nutrition and physical activity.

— Beth Conlon, PhD, MS, RDN

Are Weight Loss Supplements Safe?

Batsis explains that the supplement industry is required to follow good manufacturing practices, and mandates that new ingredients demonstrate safety prior to marketing. But that may not be enough to prove safety or efficacy.

“Based on our review, there are few high quality, efficacy-based trials for such claims suggesting that more science is needed prior to widespread recommendations,” says Batsis.  

Conlon says that supplements can contain ingredients that may interfere with underlying medical conditions, medications, and foods, so it’s important to speak to trained medical professionals before starting any new dietary supplements. 

What’s Next?

The way that weight loss supplements are studied and marketed needs to change, in order to protect consumers.

“The importance of an academic-industry partnership is critically necessary to determine efficacy of each category and to ensure studies are free of the potential for commercial bias,” says Batsis. “Longer duration trials and larger sample sizes are also needed.”

He explains that this review highlights the importance of the efforts put forth by the National Institutes of Health’s Office of Dietary Supplements to advance the science of nutritional supplementation and a need for high-quality research, and that having a partnership between researchers, funders, and industry is critically needed.

Conlon agrees and adds that academics possess a lot of knowledge of proper study design and evaluation methods but often lack resources (like money and time) to actually conduct the studies, whereas supplement companies often have the resources for studies but don't necessarily have the subject matter expertise that academics have.

“I hope that the results of this study generate discussions on how we can make those bridges happen in the near future,” says Conlon.

What This Means For You

There is little evidence that dietary supplements for weight loss are effective, and safety is not widely tested by the FDA. At Verywell Fit, we generally discourage the use of weight loss supplements due to potentially negative side effects and health concerns. As always, we recommend speaking with a healthcare practitioner prior to adding any supplement or over-the-counter drug to your regime.

 

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  1. National Institutes of Health, Office of Dietary Supplements. Dietary supplements for weight loss. Updated March 29, 2021.

  2. Batsis JA, Apolzan JW, Bagley PJ, et al. A systematic review of dietary supplements and alternative therapies for weight loss. Obesity (Silver Spring). 2021;29(7):1102-1113. doi:10.1002/oby.23110

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