Everywhere we go, we are being inundated with ads promising us that taking a few pills a day will burn fat. Turn on the television and you hear doctors recommending the latest and greatest fat burner. Here’s a little secret; most doctors take only one class in nutrition during their education, and thus know very little about nutrition and metabolism.
We’re going to take an evidence-based approach, and see what the actual scientific research says about these popular fat burners.
Let’s actually break down the marketing claims when it comes to the most popular fat burners.
Green Coffee Bean Extract
A “miracle” fat burner. It’s a source of chlorogenic acid, which gets lost when coffee beans are roasted. Chlorogenic acid is supposed to slow down your body’s absorption of glucose, which promotes weight loss.
Green coffee bean was found to have a slight effect in obese people. For people who are merely overweight, it is unlikely to have any effect. Furthermore, the positive research was industry funded, so take that research with a grain of salt.
5-HTP is converted to serotonin in the brain, which is supposed to suppress hunger.
It does suppress hunger – by making you nauseous! That is the “magic” – taking 5-HTP makes you feel nauseous, and you end up eating slightly less. It should be noted that the oft-recommended dosage of 200mg/day is well below the dosage you need before you notice it.
Superlatives used to describe this fruit-based supplement include: “breakthrough,” “magic,” “holy grail” and “body-fat buster.” Gambooge is supposed to burn fat because it is a great source of hydroxycitric acid (HCA), which is supposed to decrease your appetite. The supplement you buy is usually the HCA extracted from the fruit.
Gambooge has research on it dating back to 15 years ago. A recent systematic review (in which researchers look at all relevant research to make a general recommendation) of over 700 participants concluded that gambooge has an irrelevant effect on your bodyweight.
Gambooge is a great example of the rats vs humans issue. While it was very promising in rats, human studies found none of those benefits.
Of all the “doctor-recommended” fat burners, this is the most popular one. Extracted from raspberries, this compound is meant to promote lipolytic activity. In simpler terms, it’s supposed to cause fat breakdown.
Raspberry ketones were found effective in rat studies, at a very high dosage. That’s it. There is literally zero legitimate research done in humans. Extrapolating from some rat studies and applying them wholesale to humans is disingenuous.
Even the results in the rat studies were pathetic! It was as effective as taking a car from 42 MPG to 42.1 MPG.
There are four main polyphenols (a kind of compound commonly found in nature) in green tea. The most potent of them is EGCG, which is supposed to promote fat burning. The four polyphenols interact with each other in a health-boosting manner.
For once, a fat-burning supplement (kind of) delivers! There are human studies that shows consuming green tea/EGCG helps burn more fat and decrease your overall fat mass. While it’s not by a lot, there is at least evidence that it works!
The catch? It seems to only work on those who don’t regularly consume caffeine. If you regularly drink coffee or tea, the fat-burning effects of green tea/EGCG are heavily compromised.
The other interesting note is how healthy green tea is for you! It has positive effects throughout your body such as low-grade anti-oxidative and anti-inflammatory properties paired with a reduction in cancer risk. I drink green tea regularly (even though I think it tastes horrible) just for its health benefits.
Conjugated Linoleic Acid (CLA)
CLA is supposed to interact with the peroxisome proliferator activated receptor (PPAR) system in your body, which is related to fat metabolism inside your body.
A common theme emerges – what works in rats does not work in humans. CLA barely interacts with the PPAR system, rendering it unreliable. The end result? No fat burning.
Caffeine is supposed to increase your metabolism. This lets your body use your fat reserves for energy, which means less fat stored.
Caffeine is a potent stimulant, and does indeed increase your metabolism.
But just like green tea, caffeine only works if you are not used to it. As you become a regular user, its stimulant effects wear off, and so does the boost to your metabolism. For caffeine to be effective, you need to cycle its usage.
It should be noted that potent is relative – yes caffeine burns fat, but the bulk of your fat loss will be through your diet. Since you become used to caffeine, it is not an effective everyday fat burner. It can help, but it’s not something you can rely on every day.
7-keto, related to DHEA
Stimulates your thyroid to increase your body’s metabolism. This means less fat is stored.
7-keto is one of three oxygenated metabolites of DHEA, a naturally occurring hormone in your body. Studies do seem to indicate that 7-keto can increase your metabolism, but the quality of research is extremely iffy (due to conflicts of interest). At this time no statement can be made as to whether 7-keto works or doesn’t.
White Kidney Bean Extract
Prevents the breakdown of carbs into simple sugars, so they are not absorbed by your body. As a result, complex carbs pass through your digestive system unabsorbed.
The Reality: White kidney bean extract does seem to reduce the absorption of carbohydrates, but its potency is so weak that it has little overall effect. It’s as effective as having a few less bites of food.
L-Carnitine aka ALCAR (Acetyl-L-Carnitine)
L-Carnitine helps shuttle fats into your mitochondria (the “powerhouse” of a cell), where they get burned off.
The Reality: Another supplement which works in theory, but does not work in reality. Supplementation only works in burning fat if you are deficient (which is common only in very elderly people); taking more carnitine than your body needs results in no extra fat burning. This is likely due to your body’s regulatory facilities.
At the end of the day, even though some fat burners do work, the amount of fat they actually burn is small. Unless you are working on the last few pounds, they won’t be noticeable. Want to know what burns fat?
Check out The Fat Loss Puzzle eBook.