Supplements for Fat Loss: Do They Really Work?

Introduction

Over two-thirds of adults and almost one-third of children and adolescents in the United States are overweight or have obesity (Hales et al., 2020; Stierman et al., 2021). In the quest for weight loss, many people turn to dietary supplements promoted for their supposed fat-burning properties. However, there is little scientific evidence to support the effectiveness of most weight-loss supplements. In fact, some may even be harmful (Manore, 2012).

Despite the lack of evidence, the global weight-loss supplement market continues to grow, driven by aggressive marketing and the allure of a quick fix for weight problems. Consumers often believe that these products are safe and effective because they are “natural” or available over-the-counter. However, supplements for fat loss are not well-regulated, and their long-term safety and efficacy remain questionable.

This article will provide an overview of the most common ingredients found in weight-loss supplements, examine the scientific evidence behind their purported benefits, and discuss potential safety concerns associated with their use. By the end of this article, readers will have a better understanding of the current state of research on supplements for fat loss and be equipped to make more informed decisions about their use.

Common Ingredients in Weight-Loss Supplements

Weight-loss supplements often contain a variety of ingredients claimed to promote fat loss, increase metabolism, or reduce appetite. Some of the most common ingredients include stimulants like caffeine and green tea extract, which may slightly increase energy expenditure and fat oxidation (Jurgens et al., 2012). Protein powders and soluble fibers are sometimes added to enhance satiety and reduce calorie intake (Pittler & Ernst, 2004). Other popular ingredients like conjugated linoleic acid (CLA), garcinia cambogia, and raspberry ketones have been studied for their potential effects on fat metabolism and body composition, but evidence for their efficacy is limited and inconsistent (Onakpoya et al., 2011).

Certain herbs and plant extracts are also commonly found in weight-loss supplements. Bitter orange (Citrus aurantium) contains synephrine, a compound with stimulant effects similar to ephedrine, which was banned by the FDA due to safety concerns (Manore, 2012). Hoodia gordonii, a succulent plant from Africa, has been marketed as an appetite suppressant, but there is little evidence that it is effective (Pittler & Ernst, 2004). Yohimbine, derived from the bark of an African tree, is sometimes included for its supposed fat-burning properties, but it can cause side effects like anxiety and high blood pressure (Manore, 2012).

Minerals like chromium are often added to weight-loss supplements based on claims that they can improve insulin sensitivity and reduce body fat. However, a systematic review found that chromium supplementation had no significant effect on body weight or composition (Pittler & Ernst, 2004). Glucomannan, a soluble fiber derived from konjac root, has shown some promise for promoting weight loss by increasing feelings of fullness and reducing calorie intake (Jurgens et al., 2012). However, more research is needed to confirm its long-term efficacy and safety.

Efficacy of Weight-Loss Supplements

Despite the popularity of weight-loss supplements, most research on their efficacy is of low quality. Many studies have methodological limitations, such as small sample sizes, short durations, and lack of proper controls (Manore, 2012). Results are often inconsistent across trials, making it difficult to draw firm conclusions. A systematic review by Pittler and Ernst (2004) concluded that there was insufficient evidence to recommend any specific supplement for weight loss.

Some ingredients, like garcinia cambogia, glucomannan, and chromium, have shown potential for small short-term weight loss effects in certain studies. However, the clinical relevance of these findings is uncertain, as the observed benefits are generally modest and may not translate to significant long-term weight loss or health improvements (Onakpoya et al., 2011). More rigorous, large-scale trials are needed to evaluate the efficacy and safety of these supplements.

Caffeine and green tea catechins are two ingredients that have a bit more support from research. A meta-analysis by Jurgens et al. (2012) found that green tea supplementation led to small but statistically significant reductions in body weight and waist circumference compared to placebo. The effects were attributed to the thermogenic properties of caffeine and catechins, which may slightly increase energy expenditure and fat oxidation. However, the authors noted that the clinical significance of these modest effects is unclear, and green tea supplements are unlikely to produce substantial weight loss without accompanying lifestyle changes.

Safety Concerns

One major concern with weight-loss supplements is that they are not well regulated by the FDA. Unlike prescription drugs, supplements do not require premarket approval for safety and efficacy (Manore, 2012). This lack of oversight means that products may contain banned substances, prescription drugs, or other ingredients not listed on the label, which can be harmful to consumers. In some cases, supplements have been found to be adulterated with sibutramine, a weight-loss drug that was withdrawn from the market due to cardiovascular risks (Manore, 2012).

Even supplements containing legal ingredients may cause adverse effects in some individuals. Bitter orange, yohimbine, and high doses of caffeine have been reported to cause side effects like increased heart rate, high blood pressure, anxiety, and gastrointestinal distress (Manore, 2012; Pittler & Ernst, 2004). Garcinia cambogia and green tea extract have been linked to rare cases of liver toxicity, although the exact relationship is not clear (Crescioli et al., 2018; Navarro et al., 2017). In 2004, the FDA banned the use of ephedra in dietary supplements due to reports of serious side effects, including heart attacks and strokes (FDA, 2004).

Certain ingredients in weight-loss supplements may also interact with medications or have contraindications for specific health conditions. For example, bitter orange contains synephrine, which can have additive effects with stimulants like caffeine and may be unsafe for people with cardiovascular disease (Manore, 2012). Glucomannan and other soluble fibers can decrease the absorption of some medications, so they should be taken separately (Pittler & Ernst, 2004). To minimise potential risks, it is important for individuals to consult with a healthcare professional before taking any weight-loss supplement, especially if they have underlying health issues or are taking medications.

The Role of Diet and Exercise

While some weight-loss supplements may have modest effects on body weight or composition, it is important to emphasise that they are not a substitute for a healthy lifestyle. The most effective and sustainable way to achieve and maintain a healthy weight is through a balanced diet and regular physical activity (Heymsfield & Wadden, 2017). Supplements should be considered only as an adjunct to these fundamental lifestyle changes, not as a primary means of weight loss.

A healthy dietary pattern for weight loss should emphasise whole, minimally processed foods, such as fruits, vegetables, whole grains, lean proteins, and healthy fats. Reducing overall calorie intake is necessary for weight loss, but it is also important to focus on the quality of those calories. Diets that are overly restrictive or eliminate entire food groups may lead to nutrient deficiencies and are difficult to maintain long-term (Heymsfield & Wadden, 2017).

Regular physical activity is also crucial for weight loss and weight maintenance. The Australian Physical Activity Guidelines recommend that adults engage in at least 150 to 300 minutes of moderate-intensity or 75 to 150 minutes of vigorous-intensity aerobic physical activity per week, as well as muscle-strengthening activities at least twice a week (Department of Health, 2021). Increasing daily non-exercise activity, such as taking the stairs instead of the elevator or walking instead of driving short distances, can also contribute to overall energy expenditure and weight management (Heymsfield & Wadden, 2017).

Behavioural Strategies for Weight Loss

In addition to diet and exercise, behavioural strategies can be effective tools for promoting weight loss and long-term weight management. Self-monitoring, such as keeping a food diary or tracking physical activity, can help individuals become more aware of their habits and identify areas for improvement (Burke et al., 2011). Setting specific, measurable, achievable, relevant, and time-bound (SMART) goals can provide motivation and direction for weight loss efforts (Heymsfield & Wadden, 2017).

Developing a support system, whether through friends, family, or a structured weight loss program, can provide encouragement and accountability. Cognitive-behavioural therapy (CBT) techniques, such as identifying and challenging negative thought patterns related to food and body image, can also be helpful for some individuals (Heymsfield & Wadden, 2017). Stress management and adequate sleep are also important considerations, as high stress levels and poor sleep quality have been associated with weight gain and difficulty losing weight (Geiker et al., 2018).

Medical Interventions for Obesity

For individuals with obesity who have difficulty losing weight through lifestyle changes alone, certain medical interventions may be appropriate under the guidance of a healthcare professional. Prescription weight-loss medications, such as orlistat, liraglutide, and phentermine/topiramate, can be effective for some people when used in combination with diet and exercise (Khera et al., 2016). However, these medications can have side effects and are not appropriate for everyone.

In severe cases of obesity, bariatric surgery may be considered. Procedures such as gastric bypass, sleeve gastrectomy, and adjustable gastric banding can lead to significant and sustained weight loss, as well as improvements in obesity-related comorbidities like type 2 diabetes and cardiovascular disease (Heymsfield & Wadden, 2017). However, surgery also carries risks and requires significant lifestyle changes and long-term follow-up care.

It is important for individuals considering medical interventions for obesity to have a thorough discussion with their healthcare provider about the potential benefits and risks, as well as realistic expectations for weight loss and long-term management. A comprehensive approach that addresses diet, physical activity, behaviour, and underlying medical issues is essential for successful weight loss and improved health outcomes.

Conclusion

Based on the available evidence, there is little convincing support for the efficacy of most dietary supplements marketed for weight loss. While some ingredients, such as caffeine and green tea catechins, may have small effects on energy expenditure and fat oxidation, these benefits are unlikely to translate to clinically meaningful weight loss without accompanying changes in diet and physical activity (Manore, 2012; Pittler & Ernst, 2004). Many of the claimed mechanisms of action for popular supplements, such as reducing fat absorption or suppressing appetite, have not been consistently demonstrated in high-quality human trials (Pittler & Ernst, 2004).

In addition to the lack of strong evidence for their efficacy, many weight-loss supplements carry potential safety risks. The lack of regulatory oversight means that products may contain undisclosed ingredients or contaminants that can be harmful (Manore, 2012). Even legal ingredients like bitter orange, yohimbine, and high doses of caffeine can cause adverse effects in some individuals, particularly those with underlying health conditions (Pittler & Ernst, 2004). Rare cases of liver toxicity have been reported with certain supplements, such as garcinia cambogia and green tea extract (Crescioli et al., 2018; Navarro et al., 2017). Given these risks, it is important for consumers to be cautious and consult with a healthcare professional before using any weight-loss supplement.

Ultimately, the most effective and safest way to achieve and maintain a healthy weight is through a balanced diet and regular physical activity. Dietary supplements should not be relied upon as a sole or primary means of weight loss, as they are unlikely to produce substantial or lasting results without accompanying lifestyle changes (Manore, 2012). The best approach is to adopt a healthy dietary pattern that emphasises whole foods, such as fruits, vegetables, whole grains, and lean proteins, while limiting processed and high-calorie foods (Heymsfield & Wadden, 2017). Incorporating regular physical activity, such as brisk walking or strength training, can also help to promote weight loss and improve overall health. For individuals with obesity who have difficulty losing weight through lifestyle changes alone, certain prescription medications or surgical interventions may be appropriate under medical supervision (Heymsfield & Wadden, 2017). However, these options should be considered only after a thorough evaluation of the potential risks and benefits by a qualified healthcare provider.

Key Highlights of Learnings and Actionable Tips

• Dietary supplements for weight loss encompass a wide variety of products, including herbs, fiber, caffeine, and minerals. Many have not been proven effective and some may have harmful side effects.
• The best way to lose weight and keep it off is to follow a sensible approach that incorporates a healthy eating plan, reduced caloric intake, and moderate physical activity under the guidance of a healthcare provider.
• Dietary supplements are not regulated as strictly as drugs by the Food and Drug Administration (FDA). Manufacturers are responsible for ensuring their products are safe and label claims are truthful, but they do not require FDA approval before marketing.
• Some common ingredients in weight-loss supplements, such as bitter orange, caffeine, and green tea, can have potentially harmful side effects like increased heart rate and blood pressure. Ingredients may also interact with medications.
• Many weight-loss supplements contain multiple ingredients that have not been adequately tested in combination with one another. The safety and efficacy of multi-ingredient formulas are often unknown.
• Fraudulent and adulterated weight-loss products are common. Supplements have been found to contain undeclared drug ingredients and even controlled substances that could be harmful.
• Before taking any dietary supplements for weight loss, talk to a healthcare provider to discuss potential benefits and risks, especially if you have any health conditions or are taking medications.

What are some of the most common ingredients found in weight-loss supplements?

Some of the most common ingredients found in weight-loss supplements include:

• Caffeine – Acts as a stimulant and may increase metabolism and promote fat burning. Found in many supplements, including green tea extract.
• Green tea extract – Contains caffeine and catechins like EGCG that may increase fat oxidation. However, effects on body weight are small.
• Garcinia cambogia – Contains hydroxycitric acid (HCA) which is claimed to inhibit fat production and suppress appetite, but evidence for significant weight loss is lacking.
• Glucomannan – A soluble fiber that may promote feelings of fullness and reduce calorie intake, but weight loss effects are inconsistent in studies.
• Conjugated linoleic acid (CLA) – Claimed to reduce body fat, but effects are small and clinical relevance is questionable according to reviews.
• Bitter orange – Contains synephrine, a stimulant similar to ephedrine. May increase metabolism but can cause side effects like rapid heart rate. Safety concerns exist, especially when combined with other stimulants.

Can dietary supplements help me lose weight quickly?

While some dietary supplements may lead to small amounts of weight loss, none have been proven to be effective for substantial or rapid weight reduction. Most clinical studies show only modest weight loss of a few pounds over several weeks or months, if any.

Supplements are not a magic bullet for quick weight loss. The most effective way to achieve lasting weight loss is through lifestyle changes – consuming a healthy, calorie-controlled diet and increasing physical activity. These behaviors take time and effort but are the foundation for long-term weight management.

Some people may turn to weight-loss supplements for faster results, but using these products does not necessarily lead to long-term success. Many have not been tested for safety and efficacy, and some may have harmful side effects or interact with medications. Relying on supplements for quick weight loss is unlikely to lead to lasting results and is not a substitute for making healthy lifestyle changes.

How do I know if a weight-loss supplement is safe and effective?

Evaluating the safety and effectiveness of a weight-loss supplement can be challenging. Unlike drugs, supplements do not require premarket review and approval by the FDA. Manufacturers are responsible for ensuring product safety and accurate labeling, but the FDA does not test products before they are sold.

A few tips when considering a weight-loss supplement:

• Look for products that have been tested in human clinical trials, ideally randomized controlled trials, with results published in peer-reviewed scientific journals. Be cautious of exaggerated claims based only on animal or lab studies.
• Pay attention to dosages used in clinical studies. Effectiveness and safety may vary depending on the dose. Many supplements contain proprietary blends with undisclosed amounts of active ingredients.
• Check if the product has been tested for safety and potential side effects, especially with long-term use. Keep in mind that supplements can interact with medications and cause adverse reactions.
• Be wary of products that make extreme claims like “lose 30 pounds in 30 days” or promise rapid weight loss with no changes to diet or exercise habits. If it sounds too good to be true, it probably is.
• Talk to your healthcare provider before taking any weight-loss supplements, especially if you have health conditions or are taking medications. They can help you weigh potential benefits and risks.

Remember, just because an ingredient is natural does not necessarily mean it is safe or effective. Careful research and medical guidance are important when considering weight-loss supplements.

Are there any prescription medications available for weight loss?

Yes, there are several FDA-approved prescription medications used for weight management. These include:

• Orlistat (Xenical) – Reduces fat absorption in the intestines. Available in prescription strength and over-the-counter (Alli).
• Phentermine – An appetite suppressant that acts on the central nervous system. For short-term use only.
• Liraglutide (Saxenda) – Mimics a hormone called GLP-1 to regulate appetite. Also used to treat type 2 diabetes.
• Naltrexone/bupropion (Contrave) – Combines two drugs that act on the brain to reduce appetite and food cravings.
• Phentermine/topiramate (Qsymia) – Combines phentermine with an anticonvulsant drug. Suppresses appetite and increases feelings of fullness.
• Semaglutide (Wegovy) – A newer medication similar to liraglutide. Helps regulate appetite by acting on GLP-1 receptors.

Prescription weight-loss medications are typically reserved for people with obesity who have not been able to lose weight through diet and exercise alone, and who have health conditions related to their weight. They are used in combination with lifestyle changes, not as a substitute for healthy habits.

These medications can have side effects and are not appropriate for everyone. A doctor must determine if potential benefits outweigh risks for each individual patient. Long-term safety and effectiveness are still being researched for many of these drugs.

It’s important to note that weight-loss medications are not a quick fix or a replacement for a healthy lifestyle. They should be used as part of a comprehensive treatment plan that includes diet, exercise, and behavioral changes. Regular follow-up with a healthcare provider is necessary to monitor progress, side effects, and long-term safety.

Will I regain weight if I stop taking a weight-loss supplement?

Weight regain is a common concern after stopping the use of a weight-loss supplement or discontinuing any short-term weight-loss method. Many supplements have not been studied for their long-term effects on weight maintenance.

In some cases, people may experience a rebound effect and regain the weight they lost, or even gain more weight, when they stop using a supplement. This can happen for a few reasons:

1. Supplements do not change eating habits or activity levels. If these lifestyle factors have not been addressed, weight regain is likely when the supplement is stopped.
2. Some supplements may cause loss of water weight or lean muscle mass rather than body fat. This type of weight is more easily regained once the supplement is discontinued.
3. Certain ingredients in supplements, such as stimulants, may decrease appetite while they are being taken. When stopped, appetite may increase, leading to overeating and weight regain.
4. If a supplement was effective for weight loss, an individual might have relied on it as a “crutch” without learning sustainable lifestyle changes. Discontinuing it means losing that crutch.

The most effective way to maintain weight loss long-term is to make permanent changes to diet and exercise habits. Supplements may provide a temporary boost, but they do not teach the skills needed for lasting weight management.

If you do choose to use a weight-loss supplement, it’s best to think of it as a short-term tool within the context of a long-term healthy lifestyle plan. Focus on eating a balanced diet, controlling portions, and staying physically active. These behaviors will serve you better in the long run than relying on a supplement indefinitely. Talk to a healthcare professional about a sustainable strategy for maintaining weight loss.

References

Crescioli, G., Lombardi, N., Bettiol, A., Marconi, E., Risaliti, F., Bertoni, M., Menniti Ippolito, F., Maggini, V., Gallo, E., Firenzuoli, F., & Vannacci, A. (2018). Acute liver injury following Garcinia cambogia weight-loss supplementation: case series and literature review. Internal and Emergency Medicine, 13(6), 857-872. https://doi.org/10.1007/s11739-018-1880-4

FDA. (2004). FDA Issues Regulation Prohibiting Sale of Dietary Supplements Containing Ephedrine Alkaloids and Reiterates Its Advice That Consumers Stop Using These Products. https://www.fda.gov/news-events/press-announcements/fda-issues-regulation-prohibiting-sale-dietary-supplements-containing-ephedrine-alkaloids-and

Hales, C. M., Carroll, M. D., Fryar, C. D., & Ogden, C. L. (2020). Prevalence of obesity and severe obesity among adults: United States, 2017–2018. NCHS Data Brief, no 360. Hyattsville, MD: National Center for Health Statistics. https://www.cdc.gov/nchs/products/databriefs/db360.htm

Heymsfield, S. B., & Wadden, T. A. (2017). Mechanisms, Pathophysiology, and Management of Obesity. The New England Journal of Medicine, 376(3), 254–266. https://doi.org/10.1056/NEJMra1514009

Jurgens, T. M., Whelan, A. M., Killian, L., Doucette, S., Kirk, S., & Foy, E. (2012). Green tea for weight loss and weight maintenance in overweight or obese adults. The Cochrane Database of Systematic Reviews, 12, CD008650. https://doi.org/10.1002/14651858.CD008650.pub2

Manore M. M. (2012). Dietary supplements for improving body composition and reducing body weight: where is the evidence?. International Journal of Sport Nutrition and Exercise Metabolism, 22(2), 139–154. https://doi.org/10.1123/ijsnem.22.2.139

Navarro, V. J., Khan, I., Björnsson, E., Seeff, L. B., Serrano, J., & Hoofnagle, J. H. (2017). Liver injury from herbal and dietary supplements. Hepatology, 65(1), 363–373. https://doi.org/10.1002/hep.28813

Onakpoya, I., Hung, S. K., Perry, R., Wider, B., & Ernst, E. (2011). The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. Journal of Obesity, 2011, 509038. https://doi.org/10.1155/2011/509038

Pittler, M. H., & Ernst, E. (2004). Dietary supplements for body-weight reduction: a systematic review. The American Journal of Clinical Nutrition, 79(4), 529–536. https://doi.org/10.1093/ajcn/79.4.529

Stierman, B., Afful, J., Carroll, M. D., Chen, T., Davy, O., Fink, S., Fryar, C. D., Gu, Q., Hales, C. M., Hughes, J. P., Ostchega, Y., Storandt, R. J., & Akinbami, L. J. (2021). National Health and Nutrition Examination Survey 2017–March 2020 Prepandemic Data Files Development of Files and Prevalence Estimates for Selected Health Outcomes. National Health Statistics Reports, (158), 1–50. https://www.cdc.gov/nchs/data/nhsr/nhsr158-508.pdf