Introduction
Diet supplements for weight loss have become increasingly popular among individuals seeking to shed extra pounds. With the prevalence of obesity and overweight in the United States reaching epidemic proportions (Hales et al., 2020), many people turn to these supplements as a potential solution. However, it is crucial to evaluate the safety and efficacy of these products before incorporating them into a weight loss plan.
While some dietary supplements may offer modest benefits when combined with lifestyle changes, experts emphasise that they are not a magic bullet for weight loss. A nutritious diet and regular physical activity remain the foundation for achieving and maintaining a healthy weight (Blanck et al., 2007). It is essential to approach weight loss supplements with caution and consult with a healthcare professional to discuss potential risks and benefits.
This article will explore the current scientific evidence surrounding common ingredients found in diet supplements for weight loss, including caffeine, green tea extract, garcinia cambogia, glucomannan, conjugated linoleic acid (CLA), carnitine, and raspberry ketones. We will also discuss the role of prescription medications and lifestyle changes in the context of weight management. By examining the available research, we aim to provide a balanced perspective on the effectiveness and safety of diet supplements for weight loss.
Common Ingredients in Weight Loss Supplements
Caffeine
Caffeine is a stimulant commonly found in weight loss supplements due to its potential to increase energy expenditure and fat oxidation. A systematic review and meta-analysis by Tabrizi et al. (2019) found that caffeine intake might promote weight, BMI, and body fat reduction. However, the effects on weight loss are generally small, and high doses of caffeine can cause adverse effects such as insomnia, anxiety, and increased heart rate (Temple et al., 2017).
Green Tea Extract
Green tea extract, rich in caffeine and catechins like epigallocatechin gallate (EGCG), is another popular ingredient in weight loss supplements. A systematic review by Jurgens et al. (2012) suggested that green tea preparations may induce a small, statistically non-significant weight loss in overweight or obese adults. However, the authors concluded that the clinical relevance of this effect remains unclear. Moreover, high doses of green tea extract have been linked to liver damage in some cases (Sarma et al., 2008).
Garcinia Cambogia (Hydroxycitric Acid)
Garcinia cambogia, a tropical fruit containing hydroxycitric acid (HCA), has been marketed as a weight loss aid. A systematic review and meta-analysis by Onakpoya et al. (2011) found that HCA might cause short-term weight loss, but the magnitude of the effect is small, and the clinical relevance is uncertain. Furthermore, there have been rare cases of liver toxicity associated with garcinia cambogia supplements (Crescioli et al., 2018).
Glucomannan
Glucomannan is a soluble dietary fiber derived from the konjac plant, which is believed to promote weight loss by increasing feelings of fullness and reducing calorie intake. However, a systematic review and meta-analysis by Zalewski et al. (2015) concluded that glucomannan supplementation does not significantly affect body weight, body mass index, or waist circumference in overweight or obese individuals compared to placebo.
Conjugated Linoleic Acid (CLA)
Conjugated linoleic acid (CLA) is a naturally occurring fatty acid that has been studied for its potential weight loss effects. A systematic review and meta-analysis by Onakpoya et al. (2012) found that CLA supplementation might reduce body fat mass in the short term, but the effects are modest, and the long-term clinical efficacy and safety remain uncertain.
Carnitine
Carnitine is an amino acid derivative involved in fatty acid metabolism and energy production. A systematic review and meta-analysis by Pooyandjoo et al. (2016) suggested that carnitine supplementation might lead to greater weight loss than placebo. However, the included studies were small, and the authors concluded that more rigorous trials are needed to confirm these findings.
Raspberry Ketones
Raspberry ketones, the compounds responsible for the aroma of raspberries, have been marketed as a weight loss aid due to their purported effects on fat metabolism. However, there is a lack of human studies evaluating the effects of raspberry ketone supplementation on body weight or composition. The safety and long-term effects of these supplements also remain largely unknown (Cotten et al., 2017).
Prescription Medications for Weight Loss
In recent years, newer prescription medications for weight loss have shown more promising results in clinical trials when combined with lifestyle changes. Semaglutide (Wegovy), a glucagon-like peptide-1 (GLP-1) receptor agonist, has been found to lead to significant weight loss in individuals with obesity (Wilding et al., 2021). Similarly, tirzepatide, a dual GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist, has demonstrated substantial weight loss in clinical trials (Jastreboff et al., 2022).
However, these medications can cause side effects, such as gastrointestinal issues and increased heart rate, and are intended for individuals with obesity or overweight with a weight-related comorbidity. They also require medical supervision and should be used in conjunction with a reduced-calorie diet and increased physical activity.
Lifestyle Changes: The Foundation for Healthy Weight Loss
While diet supplements and prescription medications may play a role in weight management, experts emphasize that lifestyle changes, including a balanced diet and regular physical activity, are the cornerstone of achieving and maintaining a healthy weight. The 2020-2025 Dietary Guidelines for Americans recommend a dietary pattern that includes a variety of nutrient-dense foods, such as fruits, vegetables, whole grains, lean proteins, and healthy fats, while limiting the intake of added sugars, saturated fats, and sodium (U.S. Department of Agriculture and U.S. Department of Health and Human Services, 2020).
In addition to a healthy diet, engaging in regular physical activity is crucial for weight management and overall health. The World Health Organization (2020) recommends that adults aged 18-64 years engage in at least 150-300 minutes of moderate-intensity aerobic physical activity or 75-150 minutes of vigorous-intensity aerobic physical activity per week, as well as muscle-strengthening activities involving major muscle groups on two or more days a week.
Incorporating these lifestyle changes can lead to sustainable weight loss and improved health outcomes, such as reduced risk of chronic diseases like type 2 diabetes, cardiovascular disease, and certain cancers (Heymsfield & Wadden, 2017).
Safety Considerations and Potential Risks
When considering the use of diet supplements for weight loss, it is essential to be aware of potential safety concerns and risks. Some supplements may interact with medications, exacerbate pre-existing health conditions, or cause adverse effects (Dwyer et al., 2018). For example, high doses of green tea extract have been linked to liver damage in some cases (Sarma et al., 2008), and garcinia cambogia supplements have been associated with rare instances of liver toxicity (Crescioli et al., 2018).
Furthermore, many weight loss supplements contain a combination of ingredients, some of which may not have been thoroughly studied for safety or efficacy. It is crucial to consult with a healthcare professional before starting any supplement regimen to discuss potential risks and benefits, especially for individuals with underlying health conditions or those taking medications.
Regulation of Dietary Supplements
In many countries, including the United States, dietary supplements are not regulated as strictly as prescription medications. The U.S. Food and Drug Administration (FDA) does not require premarket review for safety and efficacy of dietary supplements before they are marketed (U.S. Food and Drug Administration, 2022). Instead, manufacturers are responsible for ensuring the safety and accurate labeling of their products.
This lack of rigorous regulation has led to concerns about the quality, purity, and safety of some weight loss supplements. In some cases, supplements have been found to contain undeclared ingredients, contaminants, or even banned substances (Tucker et al., 2018). Therefore, it is essential for consumers to exercise caution when selecting and using weight loss supplements, and to choose products from reputable manufacturers that adhere to good manufacturing practices and voluntary quality standards.
The Bottom Line
While diet supplements for weight loss are popular among individuals seeking to shed excess pounds, the scientific evidence supporting their efficacy and long-term safety is limited. Some ingredients, such as caffeine, green tea extract, and garcinia cambogia, may lead to modest short-term weight loss, but the effects are generally small, and the clinical relevance remains uncertain. Other supplements, like glucomannan and raspberry ketones, lack sufficient evidence to support their use for weight management.
Prescription medications, such as semaglutide and tirzepatide, have shown more promising results in clinical trials when combined with lifestyle changes. However, these medications can cause side effects and require medical supervision, and are intended for individuals with obesity or overweight with a weight-related comorbidity.
Ultimately, lifestyle changes, including a balanced diet and regular physical activity, remain the foundation for achieving and maintaining a healthy weight. While diet supplements may have a role as part of a comprehensive weight management plan, they should not be relied upon as a sole solution or a substitute for healthy lifestyle habits.
It is crucial for individuals considering the use of diet supplements for weight loss to consult with a healthcare professional to discuss potential risks and benefits, and to choose products from reputable manufacturers. By prioritizing evidence-based strategies and adopting a holistic approach to weight management, individuals can work towards achieving sustainable, healthy weight loss and improved overall health.
Conclusion
In conclusion, while diet supplements for weight loss have gained significant popularity, the scientific evidence supporting their efficacy and long-term safety remains limited. Some common ingredients, such as caffeine, green tea extract, and garcinia cambogia, may lead to modest short-term weight loss, but the effects are generally small, and their clinical relevance is uncertain. Other supplements, like glucomannan and raspberry ketones, lack sufficient evidence to support their use for weight management.
It is crucial to approach weight loss supplements with caution and to prioritise evidence-based strategies for achieving and maintaining a healthy weight. Lifestyle changes, including a balanced diet and regular physical activity, remain the cornerstone of successful weight management. While diet supplements may play a role as part of a comprehensive approach, they should not be relied upon as a sole solution or a substitute for healthy lifestyle habits. Newer prescription medications, such as semaglutide and tirzepatide, have shown more promising results in clinical trials when combined with lifestyle modifications. However, these medications can cause side effects and require medical supervision.
Ultimately, individuals considering the use of diet supplements for weight loss should consult with a healthcare professional to discuss potential risks and benefits, and to ensure that any supplement use is part of a holistic, evidence-based approach to weight management. By focusing on sustainable lifestyle changes and seeking guidance from qualified healthcare providers, individuals can work towards achieving their weight loss goals while prioritising their overall health and well-being.
Key Highlights and Actionable Tips
- Weight loss is a priority goal for many and essential for wellbeing and healthy living
- Nutrition Warehouse stocks Australia’s most trusted brands of weight loss supplements
- Products range from thermogenic fat burners to carb blockers, CLAs, L-Carnitine, Acetyl L-Carnitine, 7-Keto, fat metabolisers and women’s weight loss supplements
- Consuming these supplements alongside a healthy diet and exercise routine can help improve body composition, increase muscle mass and boost energy
What are the most popular types of weight loss supplements?
Some of the most popular types of weight loss supplements include thermogenic fat burners, which aim to boost metabolism and increase fat burning; carb blockers that reduce the absorption of carbohydrates; conjugated linoleic acid (CLA) which may help reduce body fat; L-Carnitine and Acetyl L-Carnitine which play a role in energy production and fat metabolism; and specialised women’s weight loss supplements that often contain ingredients like green tea extract and caffeine.
How do weight loss supplements work in the body?
Different types of weight loss supplements have varying mechanisms of action in the body. For example, thermogenic fat burners often contain stimulants like caffeine which can boost metabolic rate and encourage the body to burn more fat for fuel. Carb blockers usually contain ingredients that inhibit enzymes involved in carbohydrate digestion, reducing the amount of carbs absorbed. CLA is thought to reduce fat accumulation and increase fat burning, while L-Carnitine helps transport fatty acids into mitochondria to be used for energy production.
Can weight loss supplements replace a healthy diet and exercise?
No, weight loss supplements should not be seen as a replacement for a healthy diet and regular physical activity. While they may provide some benefits, they work best when used in conjunction with lifestyle modifications. Eating a balanced diet, controlling portion sizes and engaging in exercise are still the foundations of successful, sustainable weight loss. Supplements can support these habits but are not a magic solution on their own.
Are there any potential side effects of weight loss supplements?
Some weight loss supplements can cause side effects, particularly those containing stimulants like caffeine which may lead to jitteriness, rapid heartbeat and insomnia if consumed in excess. Gastrointestinal side effects like bloating and diarrhoea are also relatively common. Certain ingredients like synephrine and ephedra have been linked to more serious adverse effects in some cases. It’s important to follow dosage instructions, choose reputable brands and consult a healthcare professional if you have any concerns or pre-existing medical conditions.
How can I choose an effective weight loss supplement?
When selecting a weight loss supplement, look for products from reputable brands that list all ingredients clearly on the label. Check if the ingredients and doses used align with those shown to be effective in scientific research. Read reviews from other customers to get an idea of a product’s efficacy and safety. Where possible, opt for supplements that have undergone third-party testing to ensure purity and potency. Finally, keep in mind that individual results can vary and no supplement is a miracle solution, so have realistic expectations and be prepared to make healthy diet and lifestyle changes as well.
References
Blanck, H. M., Serdula, M. K., Gillespie, C., Galuska, D. A., Sharpe, P. A., Conway, J. M., Khan, L. K., & Ainsworth, B. E. (2007). Use of nonprescription dietary supplements for weight loss is common among Americans. Journal of the American Dietetic Association, 107(3), 441–447. https://doi.org/10.1016/j.jada.2006.12.009
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
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
Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M. C., & Stefanski, A. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. The New England Journal of Medicine, 387(3), 205–216. https://doi.org/10.1056/NEJMoa2206038
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
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
Onakpoya, I. J., Posadzki, P. P., Watson, L. K., Davies, L. A., & Ernst, E. (2012). The efficacy of long-term conjugated linoleic acid (CLA) supplementation on body composition in overweight and obese individuals: a systematic review and meta-analysis of randomized clinical trials. European Journal of Nutrition, 51(2), 127–134. https://doi.org/10.1007/s00394-011-0253-9
Onakpoya, I., Posadzki, P., & Ernst, E. (2014). The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials. Journal of the American College of Nutrition, 33(1), 70–78. https://doi.org/10.1080/07315724.2014.870013
Pooyandjoo, M., Nouhi, M., Shab-Bidar, S., Djafarian, K., & Olyaeemanesh, A. (2016). The effect of (L-)carnitine on weight loss in adults: a systematic review and meta-analysis of randomized controlled trials. Obesity Reviews, 17(10), 970–976. https://doi.org/10.1111/obr.12436
Sarma, D. N., Barrett, M. L., Chavez, M. L., Gardiner, P., Ko, R., Mahady, G. B., Marles, R. J., Pellicore, L. S., Giancaspro, G. I., & Low Dog, T. (2008). Safety of green tea extracts: a systematic review by the US Pharmacopeia. Drug Safety, 31(6), 469–484. https://doi.org/10.2165/00002018-200831060-00003
Wilding, J., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., McGowan, B. M., Rosenstock, J., Tran, M., Wadden, T. A., Wharton, S., Yokote, K., Zeuthen, N., & Kushner, R. F. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England Journal of Medicine, 384(11), 989. https://doi.org/10.1056/NEJMoa2032183
Zalewski, B. M., Chmielewska, A., & Szajewska, H. (2015). The effect of glucomannan on body weight in overweight or obese children and adults: a systematic review of randomized controlled trials. Nutrition, 31(3), 437–442.e2. https://doi.org/10.1016/j.nut.2014.09.004
