Ever been curious if any fat burners are really backed by science? If so, and if you could only read one research paper to get the answer, it would be this one: “Comparing the effectiveness of fat burners and thermogenic supplements to diet and exercise for weight loss and cardiometabolic health.” This study was published in the scientific journal Nutrition And Health. (Clark et al 2021). I’ll summarize it for you in 3 minutes…

Bottle of worthless fat burners

The reason this study is so important is that it wasn’t a single study, it was a systematic review and meta-analysis. (A study of studies). This is the strongest type of evidence you can get.

Always remember, it’s often possible to find a single study to support a position or bias, but when you look at the entire body of research on a topic, the truth comes out.

In this case, there were 21 studies on fat burners evaluated. They all had a duration of at least 8 weeks and involved subjects who were overweight.

In these studies, all the usual over-the-counter thermogenic suspects were examined, including green tea, green coffee bean, garcinia, caffeine, capsaicin, L-carnitine, synephrine, and ephedrine (technically a drug, and now banned).

Here was the author’s conclusion:

“There was no indication that fat burners and thermogenic dietary supplements were any more effective than exercise or a combination of diet and exercise.”

This shows that the claim, “Fat burners can give you more fat loss than diet, exercise, or exercise plus diet” is complete nonsense. Yet how many times have you seen supplement ads boasting “Burn fat without diet or exercise?” I’ve seen that claim for decades and still do. According to the FTC, this is illegal advertising.

But what about the studies where one group used exercise and diet with no supplements, and the other group used diet and exercise too, but also added the supplements? Wouldn’t that do something?

Not according to science. All the studies found the same thing: No benefit, or a trivial benefit which doesn’t add up to significant fat loss over time.

In this study, they also looked at the effect of fat burners on health (cardiometabolic markers such as blood cholesterol and blood pressure). Out of the 21 studies included, 10 of them reported adverse effects. Here’s what the scientists said:

“Changes induced in health status due to supplement use were no better, and somewhat worse, than those induced from exercise or a combination of diet and exercise used for comparison.”

Then they got specific and listed some of the potential dangers:

“We must draw attention to the ever-growing reports of adverse effects and negative outcomes from the use of purported fat burner supplements. This list of adverse outcomes includes Rhabdomyolysis, ischemic stroke, and sudden cardiac death stemming from using these supplements in conjunction with diet and exercise.”

“Additionally are the reports of hepatic and renal issues that are associated with the use of sympathomimetic dietary supplements. More troubling are the reports of psychiatric, cognitive, and sleep disturbances associated with the use of thermogenic substances.”

So, I can summarize like this: Hapless consumers spend 38 billion a year (on all weight loss supplements combined) for somewhere between zero and trivial fat loss benefit, with side effects including potential liver and kidney damage and risk of stroke and death. Sounds awesome. Where do I sign up?

Despite this kind of strong evidence, some people are staunch supporters for these supplements and will argue to the death about it.

Lately, this might be because a newer study (Siedler 2023) appeared to show that a multi-ingredient over the counter fat burner actually did have a thermogenic effect. (A 112 calorie per day increase in energy expenditure). This one has been making the rounds for months, and that’s one reason why fat burners are in the news and social media so much again.

I read the study, and in an ironic twist, it turns out that while it’s true there was a minor thermogenic effect, at the end of the study there was zero change in body composition. This is most likely due to building tolerance over time and also due to compensation. (When energy expenditure goes up, most people compensate by eating more later).

In addition, there was zero change in eating behaviors (the product didn’t suppress appetite as advertised).

It’s your money, but my advice is to save it. Fat burners are a waste.

If you’re a Burn the Fat Inner Circle member and you want to see my complete 2024 fat burner report including my write up of the 2023 fat burner study, and my further explanation why fat burners are a waste of money, then log in and check it out here:

==> www.burnthefatinnercircle.com/members/Fat-burners-dont-work.cfm (members only)

Not a member? Join us here:

==> www.burnthefatinnercircle.com/membership-details

Train hard and expect success!

– Tom Venuto,
Author, Burn the Fat, Feed the Muscle
Founder, Burn The Fat Inner Circle,
All-Natural, No-BS Body Transformation

tomvenuto-blogAbout Tom Venuto
Tom Venuto is a natural bodybuilding and fat loss expert. He is also a recipe creator specializing in fat-burning, muscle-building cooking. Tom is a former competitive bodybuilder and today works as a full-time fitness coach, writer, blogger, and author. In his spare time, he is an avid outdoor enthusiast and backpacker. His book, Burn The Fat, Feed The Muscle is an international bestseller, first as an ebook and now as a hardcover and audiobook. The Body Fat Solution, Tom’s book about emotional eating and long-term weight maintenance, was an Oprah Magazine and Men’s Fitness Magazine pick. Tom is also the founder of Burn The Fat Inner Circle – a fitness support community with over 52,000 members worldwide since 2006. Click here for membership details

Scientific References:

Clark J, et al, Comparing effectiveness of fat burners and thermogenic supplements to diet and exercise for weight loss and cardiometabolic health; systematic review and meta-analysis, Nutr Health, 27:4, 445-459, 2021.

Siedler M, et al, Nutrients, Chronic thermogenic dietary supplement consumption: Effects on body composition, anthropometrics, and metabolism, 15:4806, 2023

Subscribe to the Burn the Fat weekly newsletter and get my ebook, "The 20 Best Fat-Burning, Muscle-Building Recipes Of All Time" FREE!
Your email is safe with me!