What are fat burners? And how do they work?

What are fat burners? And how do they work?

To help you navigate this article, we've included a table of contents linking to each section:

What are fat burners?  
How do fat burners work?
What foods are natural food burners?
Common Fat Burner ingredients
How does a diet support fat burners?   
When to take fat burners
Which fat burners work the best?

What are fat burners?   

In order to lose weight, an individual needs to burn more calories than they consume and burn. There may come a point where someone needs a little extra help, so you turn to fat burners. Fat burners (both natural and synthetic) are food and nutritional supplements, have fat burning properties and can aid a healthy diet and exercise plan.

What’s important to remember is that the most effective way to burn fat is with a structured exercise and nutrition plan. No one can out train a bad diet, or pop a few fat burning pills whilst sitting on their arse all day. It takes effort. 

Here’s what you need to know about some of the most common compounds found in fat-burning supplements, so you can make the most informed decision about which products you want to take

How do fat burners work?

Often, fat burners contain a number of ingredients that are synergistic with each other. Each individual ingredient has its own proposed mechanism of action. It is often claimed that the combination of a number of these substances will have additive effects.

In the journal of Obesity Reviews, the term "fat burner" is used to describe: "nutrition supplements that are claimed to acutely increase fat metabolism or energy expenditure, impair fat absorption, increase weight loss, increase fat oxidation during exercise, or somehow cause long-term adaptations that promote fat metabolism (1)

Some natural fat burners, however, may help the body burn more fat by increasing metabolism or reducing hunger. Overall, the idea of fat burners is either to assist the body in using fat as an energy substrate, or increase the amount of energy the individual expends.

What foods are natural food burners?

There are components of food that work as natural fat burners

Cayenne Pepper - Research suggests consuming this spicy red chili pepper with a meal increases fullness (satiety). It suppresses appetite and also reduces cravings for salty or sweet foods.

Capsaicin – This is the ingredient in peppers responsible for the spiciness within them. Research has shown that when you consume this, it increases the body temperature so more calories are burned (Called the thermogenic effect of food).  

Organic raw apple cider vinegar – Apple cider vinegar has been used for years as it can help to normalise insulin levels. It may also suppress appetite, possibly by increasing your body's feeling of fullness. (2)

Protein powder – Increasing amount of protein consumed increases satiety. Protein also requires more energy to break it down into its substrates when compared to carbohydrates and even fats.

Extra Virgin Olive oil  - A study found that using extra virgin olive oil (EVOO) in meals increased the amount of fat burned for up to five hours after eating. In the study, this is called postprandial fat oxidation. EVOO also increased diet-induced thermogenesis (3)

Common Fat Burner Ingredients 

Caffeine - Caffeine is absorbed from foods and beverages with a time to peak plasma concentration of 30–90 min and half‐life of approximately 4–6h. Caffeine has been shown to increase sympathetic nervous system (SNS) activity, which can liberate fatty acids from the adipose tissue or intramuscular stores. It has also been suggested from in vitro studies that caffeine inhibits phosphodiesterase  (4), the enzyme responsible for degrading cyclic AMP (cAMP). An increase in the cAMP half‐life enhances lipolysis, subsequently increasing fatty acid availability for fuel use. 

Carnitine - found in red meat and dairy products. During overnight fasted state and during exercise of low to moderate intensity, long‐chain fatty acids are the main energy sources used by most tissues, including skeletal muscle. L-carnitine transports long-chain fatty acids across the mitochondrial inner membrane. Once inside, the fatty acids are degraded to acetyl-CoA through β –Oxidation which gives the individual their energy.

Chromium - Chromium is a trace element that is present in foods such as brewer's yeast, American cheese, mushrooms and wheat germ, and it is considered an essential nutrient. Picolinic acid is an organic compound that binds chromium and is thought to enhance the absorption and transport (5).

Green tea extracts - Tea originates from the leaves of Camellia Sinensis L, a species of the Theaceae family. The most abundant of the catechin polyphenols are epicatechin, epigallocatechin, epicatechin‐3‐gallate and epigallocatechin‐3‐gallate (EGCG), the latter being the most abundant and pharmacologically active.  Catechins, more specifically EGCG, are thought to stimulate fat oxidation through direct inhibition of catechol‐O‐methyltransferase (COMT), an enzyme that degrades norepinephrine (6). This acute increase in SNS stimulation results in elevated concentrations of catecholamines, thus potentially increasing fatty acid mobilization and oxidation. 

Conjugated linoleic acid (CLA) - It has been suggested that CLA can act as an anti‐obesity agent. This is through its multitudinal ability to decrease energy and food intake, decrease lipogenesis and increase energy expenditure, fat oxidation and lipolysis. Conjugated linoleic acids (CLA) are a group of positional and geometric isomers of the omega‐6 essential fatty acid linoleic acid. Cis‐9,trans‐11 (c9,t11) is the major isomer found in foods such as beef, lamb, milk and cheese.  In human studies, modest fat loss may be achieved through long‐term supplementation of 3 g d−1 CLA.

How does your diet support fat burners?

To burn fat, a person cannot rely on a single food or supplement. You also need to reduce their total calorie intake and increase physical activity levels. Recognise any cravings you have, and try and satisfy them with fruits, vegetables or just staying hydrated. 

When to take fat burners

Since fat burners can give you energy and suppress your appetite, taking them at strategic times of day will help you get the most from them.

Fat burners with any sort of caffeine, synephrine, yohimbe or similar ingredients in them will help raise your energy and kick start any fat burning. This might be first thing in the morning when you wake up, or you could take it 30 minutes before a workout as a pre-workout. These fat burners are categorised as “Stimulant fat burners”.

Fat burners with appetite suppressing properties should be taken at your hungriest point in the day – the time when you struggle with the hunger pangs or cravings. One strategy is to take it 30 minutes prior to a meal so you feel more satiated. These are generally non-stimulant thermogenics, and the effects can be subtle but a better choice if you are sensitive to caffeine or have high anxiety levels.

Fat burners shouldn’t be the “go-to” method when you start your weight loss regime. Ideally, these should be taken in the last few weeks of your diet to help lose those last few lbs and % body fat.

Cycle your fat burner

Overuse of caffeine and similar ingredients can lead to high levels of cortisol (the stress hormone that in high levels can break down muscle and cause fat storage). Adding to this side effect, your body can respond by slowing down your natural metabolic process to compensate. So now you're burning fewer calories, which defeats the purpose of taking a weight-loss supplement. So avoid this by cycling your supplement and taking a break. Use a ratio of 2 week on, to 1 week off. So you could cycle 2:1, or 4:2.

Which fat burners work the best?

Cobra Labs The ripper

Olympus LabsBloodshr3d Black magic edition

Fusion SupplementsRocket fuel

Hydrapharm - Hydralean


At the end of the day, the most important part of a weight loss/body fat loss plan is hard work, training and smart nutrition plan. But you can incorporate fat burners to help maximise your efforts. Fat burners have been shown (in both animal and human studies) to boost energy and increase metabolism which can aid oxidation of fat.

To get the most from synthetic and natural fat burners, it is best to include them as part of a balanced, healthful diet. Do not rely on them to burn fat on their own or assume that eating a new food will produce instant results.

Combine a good diet, exercise and supplement plan to help your reach your goals.


  1. Jeukendrup, A. E., & Randell, R. 2011. Fat burners: nutrition supplements that increase fat metabolism. Obesity Reviews. 12(10): 841-851
  2. Frost G, et al. 2014. The short chain fatty acid acetate reduces appetite via a central homeostatic mechanism. Nat Commun. 5:3611.
  3. Soares MJ, et al. 2004. The acute effects of olive oil v. cream on postprandial thermogenesis and substrate oxidation in postmenopausal women. Br J Nutr. 91(2):245-252.
  4. Dulloo, AG, Geissler, CA, Horton, T, Collins, A, Miller, DS. 1989. Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and post-obese human volunteersAm J Clin Nutr. 49: 44– 50.
  5. Hallmark, MA, Reynolds, TH, DeSouza, CA, Dotson, CO, Anderson, RA, Rogers, MA.1996. Effects of chromium and resistive training on muscle strength and body composition.Med Sci Sports Exerc. 28: 139– 144.
  6. Dulloo, AG, Duret, C, Rohrer, D, Girardier, L, Mensi, N, Fathi, M et al. 1999. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24‐h energy expenditure and fat oxidation in humans. Am J Clin Nutr. 70: 1040– 1045.

About the Author

Reggie Johal

Reggie Johal is the founder of Predator Nutrition, a UK based health and supplement store. Reggie owes much of his extensive strength and fitness knowledge to his former career as a Great Britain American Footballer.