I’m pretty sure that almost everyone who has ever thought about their health and fitness has wanted a way to lose fat as quickly and easily as possible, and since fat burner supplements promise to do exactly this, it’s easy to see why they’re such an attractive option.
But do they actually work? And are they safe? This article is going to dive into the truth about fat burners, looking at the mechanisms through which they could work, potential side effects, as well as an examination of 5 of the most popular fat burner supplements.
How Do Fat Burners Work?
Logically, fat burners can only work through one of four mechanisms:
- They reduce your appetite (So you consume fewer calories)
- They increase the amount of calories you burn (your ‘metabolic rate’) through things like thermogenesis.
- They reduce absorption of certain nutrients
- They increase the rate at which fatty acids are released from fat cells
Potential Downsides and Side Effects
- Products that work through method 2 (increasing your metabolic rate) tend to be stimulants like caffeine. Consuming excess amounts of these can disrupt sleep and increase anxiety.
- Products that work through method 3 (reducing absorption) often lead to gastrointestinal issues.
- Products that work through method 4 (increasing fatty acid release rate) may contribute to increased insulin resistance, a major problem factor in diabetes.
- Many Fat Burner supplements also raise adrenaline levels in your body, which could be problematic if you have high blood pressure or cardiac issues.
- Since lots of fat burner supplements are what’s known as ‘neurologically active’ they may interfere with other neurologically active compounds such as anti-depressants.
*If you are considering using a fat burner supplement, make sure that you consult with your doctor first.
Popular Fat Burner Supplements Examined
Caffeine (Either in coffee or tablet form)
How Is It Supposed to Work?
Methods 1, 2, and 4. Reducing appetite, increasing metabolic rate and promoting release of fatty acids.
Does it Actually Work?
Yes, there is good evidence that caffeine does all of the above. See here for more detail. Moreover, a 2019 meta-analysis (Tabrizi et al.) concluded that increased caffeine usage was correlated with weight, BMI and bodyfat reduction.
Side Effects?
Yes. Minor. Caffeine, especially in higher doses, has been known to increase anxiety and prevent quality sleep. In lower doses, however, it has been shown to be safe.
Ephedra (and Ephedrine)
How Is It Supposed to Work?
Pathway 2. Increased metabolic rate
Does it Actually Work?
Yes. A large-scale meta-analysis (shekelle et al. 2003) showed an average of 0.9kg more weight loss than placebo when used for 8+ weeks.
Side Effects?
Yes. Serious. The same studied showed that using the supplements was “associated with increased risk of psychiatric, autonomic, or gastrointestinal symptoms, and heart palpitations”
Fibre
How Is It Supposed to Work?
Pathway 1. Reduced Appetite
Does it Actually Work?
Yes. Fibre is well-established is making people feel more full.
Side Effects?
Generally no. However, when eaten in excess it can cause bloating and abdominal pain.
Green Tea / Herbal Tea and Extracts
How Is It Supposed to Work?
Pathway 2. Increased metabolic rate
Does it Actually Work?
If they contain caffeine, then yes.
Side Effects?
When used occasionally, no. However, when drank in excess various herbal and green tea type drinks have been associated with liver toxicity (Yellapu et al. 2011) The list includes…
“Chaso, Onshind, Sennomotounou (Japan); Green tea extracts (eg, Exolise [ArkoPharma-France]); Hydroxycut (Iovate, Canada); The Right Approach (Pharmanex-USA); LipoKinetix (Syntrax, USA); Ma Hung; Pure usnic acid; Kombucha mushroom.”
Yohimbine
How Is It Supposed to Work?
Pathway 2. Increased metabolic rate
Does it Actually Work?
Yes, current research shows that it increases adrenaline levels in the body when consumed on an empty or low stomach.
Side Effects?
Yes. Moderate. Increased likely of anxiety, tachycardia, gastrointestinal distress and hypertension.
Are Fat Burner Supplements A Good Choice?
Honestly, No. For 3 reasons…
- Many of them simply do not work.
- Even when they do work, the effects are very small (around 1kg in 8 weeks)
- Most of them come with serious side effects to your physical and mental health that far outweigh any possible benefit.
Our Advice for Fat Loss
- Instead of spending your money buying fat loss supplements that MIGHT help you get 2 or 3% closer to your goal, spend your money buying quality, healthy food that will help you get 80-90% closer.
- Instead of spending your time reading about fat burners, spend your time reading about topics like calorie balance, macronutrients and TDEE (total daily energy expenditure)
Maybe one day there will be an incredibly effective, completely safe fat burner supplement. Right now, however, the truth is that it doesn’t exist. (Except for caffeine perhaps, but let’s be honest, we’re all ALREADY drinking coffee)
Focus on consistently applying the fundamental principles of diet and exercise over time. Eat plenty of protein and vegetables, reduce ‘junk’ food intake, walk more, go to the gym more. Stick to the plan.
References Shekelle, P. G., Hardy, M. L., Morton, S. C., Maglione, M., Mojica, W. A., Suttorp, M. J., Rhodes, S. L., Jungvig, L., & Gagné, J. (2003). Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis. JAMA, 289(12), 1537–1545. Tabrizi, R., Saneei, P., Lankarani, K. B., Akbari, M., Kolahdooz, F., Esmaillzadeh, A., Nadi-Ravandi, S., Mazoochi, M., & Asemi, Z. (2019). The effects of caffeine intake on weight loss: a systematic review and dose-response meta-analysis of randomized controlled trials. Critical reviews in food science and nutrition, 59(16), 2688–2696. Yellapu, R. K., Mittal, V., Grewal, P., Fiel, M., & Schiano, T. (2011). Acute liver failure caused by 'fat burners' and dietary supplements: a case report and literature review. Canadian journal of gastroenterology. 25(3), 157–160.