Fat burners increase your fat metabolism and block fat absorption. They’re used to help with weight loss and to increase fat oxidation when you exercise.
Fat burners generally contain several ingredients, each with its own mechanism. This combination often has synergistic effects, and there’s a long list of ingredients that experts claim significantly improve fat metabolism.
Some of the most popular ingredients are green tea, cayenne pepper, caffeine, vitamin B6, vitamin B12, chromium and zinc. In particular, caffeine and green tea have data to confirm their fat-metabolising properties.
The rate at which these ingredients are discovered and used by the fitness industry seems to outpace the rate at which their effectiveness is verified by scientific research.
Reported Effects of Fat Burners
They Increase Your Metabolic Rate
You use energy whatever you do. Even if you’re just relaxing on the sofa at home. Obviously, you won’t be using as much as if you were intensely working out, but you’ll still be using energy.
Essentially, your metabolism determines how efficiently you burn fat. An efficient metabolism is crucial for proper fat burning and if your metabolism is slow, you won’t burn as much as you should.
Fat burners increase your metabolic rate. Accordingly, if you take a fat burner, you’ll burn more calories, even if you’re resting.
They Control Your Appetite
Fat burners can reduce food cravings. When they have cravings, many people may reach for sugary snacks or crisps. The problem is that these snacks switch off your fat burning mechanism and boost your fat storage mechanism.
Taking a fat burner between your meals helps you to curb these irritating hunger pangs. Consequently, this can help you to reduce your intake of fatty foods.
They Boost Your Energy
Fat burners are designed to increase your energy. You may experience low energy if you’re doing a lot of intense gym work, particularly cardio sessions. Burning fat this way consumes a lot of energy.
Most fat burners contain some stimulants. These stimulants help to drive you through your hardcore weights and cardio sessions.
In fact, they can boost your energy for doing anything. Even going for a stroll, for example.
They Help Burn Your Adipose Tissue
Adipose tissue is responsible for storing fats. It chiefly occurs under your skin (subcutaneous fat) and also around your internal organs (visceral fat).
Men accumulate visceral fat, which can cause the ‘beer belly’. Women store subcutaneous fat around their buttocks and thighs.
There are two types of adipose tissue. White adipose tissue occurs around your waist and thighs. Brown adipose tissue mainly occurs around your neck.
White adipose tissue provides you with insulation and energy whilst brown adipose tissue helps produce heat.
Some fat burner ingredients, such as green coffee bean extract, help you burn adipose tissue by decreasing glucose in your liver. Consequently, because your glucose levels are significantly reduced, this compels you to use stored fat cells for energy.
Common Ingredients Found in Fat Burners
Green Tea Extract
Green tea contains polyphenols called catechins (1). It also contains a lot of caffeine, a strong stimulant.
Green tea helps you burn fat in a number of ways. Initially, it boosts your metabolic rate. Then it releases stored energy from your fat cells.
Finally, it ensures you’ll burn more calories by heightening your overall energy use.
Researchers found that green tea helps keep weight off too. Further clinical trials also determined that green tea can increase daily fat-burning by 16%.
Cayenne pepper contains capsaicin which increases insulin sensitivity. This helps improve the way you store carbohydrates, potentially by up to 24%.
Cayenne also possesses powerful thermogenic properties and helps you burn fat by increasing your metabolism. Additionally, it optimises your oxidation of fats and also steps up your energy consumption.
Caffeine works by stimulating your nervous system which it does by inhibiting your adenosine receptors. It also increases your energy, especially when you’re eating less.
Additionally, caffeine increases your brain function and focus, helping to make you more alert.
Vitamin B6 (pyridoxine) increases your fat oxidation and metabolism. It also helps you absorb amino acids, the building blocks of protein and muscle.
Not only that, but it helps you to avoid overeating and, consequently, to regulate carbohydrate and fat intake.
Vitamin B12 enables you to optimise energy use from the food you eat.
It also helps you digest fatty acids, break down carbohydrates and also helps you synthesise proteins.
Vitamin B12 helps boost metabolism and increases your training tolerance, enabling you to go harder and longer. And it’ll help you cope with your decrease in food intake by stabilising your mood and strengthening your immune system.
Chromium is a trace element which helps control your insulin levels. Insulin is the hormone that regulates your carbohydrate storage.
Additionally, chromium also accelerates your metabolism, decreases food cravings and even improves your energy levels.
Clinical trials show that chromium also suppresses your appetite, helping you to consequently lose more fat (4).
Chromium seems to be overlooked and it’s neglected in many peoples’ diets. High-sugar diets may cause a chromium deficiency as sugar exacerbates its excretion in urine.
Zinc increases testosterone production, which increases your synthesis of protein.
It also helps you break down carbohydrate, fat, and proteins into useful forms to support your energy levels. If you’re going hard to get fit, this is especially important.
A clinical trial showed that obese teenagers given zinc for eight weeks, increased their metabolism of glucose and decreased the levels of fat in their blood (5). Further research demonstrated that if you have low zinc levels you may have a higher risk of excess body fat.
Side-Effects of Using Fat Burners
Most of the side-effects from fat burners inevitably come from the stimulants that prolong your energy levels whilst you’re cutting down your food intake.
Side-effects mainly occur if the manufacturer has dosed the stimulants too high.
Caffeine particularly can cause the following side effects if you take too much:
- Gastrointestinal problems
- Hypertension (high blood pressure)
- Increased heart rate
Fat Burner Dosage
The best way to take fat burners is to take four equivalent doses equally spaced throughout the day.
That way you get as close to a constant fat-burning regimen as you can, minimizing peaks and troughs.
You’re fully using each dose and ensuring fat-burning for the maximum possible time.
- Hursel R et al. The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: A meta-analysis. Obes. Rev. 2011; 12: e573–e581
- Maridakis, V et al. Caffeine Attenuates Delayed-Onset Muscle Pain and Force Loss Following Eccentric Exercise. J Pain. 2007; 8(3): 237–24
- Keijzers, GB et al. Caffeine can decrease insulin sensitivity in humans. Diabetes Care. 2002; 25(2):
- Anderson, RA. Effects of chromium on body composition and weight loss. Nutr Rev. 1998; 56(9): 266-70
- Freire, SC et al. Dietary intervention causes redistribution of zinc in obese adolescents. Biol Trace Elem Res. 2014; 154(2): 168-77