The Only Fat Burners That Actually Work (and Other Ways to Fight Flab)


Can supplements help you lose weight? We compare the best fat burners you can buy in a bottle with the finest natural alternatives

Nick Hutchings
12 Feb 2016

If you’re looking to shed weight fast, fat burners are becoming an increasingly popular option – when used wisely. They’re designed to speed up the rate you can lose weight when combined with a healthy diet and regular exercise.

Though you’ll still need a healthy dose of willpower to combat bad food decisions, fat burners can help by suppressing your appetite and keeping up your energy levels even on a calorie-restricted diet – making it much easier to make healthier food choices.

Fat burners (or thermogenics as they’re otherwise known) aren’t for everyone, though. Their high caffeine content can play havoc with your sleep patterns, while some of the ingredients can have more serious, unwanted side effects if they’re not taken properly. Here, we take a closer look at the benefits and disadvantages of fat burners and how to use them safely, as well as offering some alternative fat-torching supplements for you to consider.

You'll also want to combine them with a sensible diet, read our get lean in four weeks diet plan for a good place to start.

What are Fat Burners?

Fat burners are blends of herbs and stimulants that slightly increase your body temperature, which can help you to burn more calories during exercise. Caffeine, green tea and the South American herb yerba mate are all key players that get the green light. But there are other more dubious ones on the market too. Evidence is thin on the ground for the effectiveness of carnitine, forskolin and ephedrine. The latter is a synthetic version of the Chinese herb ephedra and used to be a key ingredient in a lot of brands, but it’s now only available on prescription in the UK because of its harmful side effects and addictive qualities.

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What Do They Do?

Some fat burners simply burn calories as heat. Others also claim to stimulate the release of adrenaline, increase your metabolic rate or act as appetite suppressants. The evidence for them working is limited, though. “A careful calorie intake and exercise are likely to produce better weight-loss results in the long term,” says nutrition expert Anita Bean.

Who Shouldn’t Take Fat Burners?

“Fat burners raise cortisol – a stress hormone – so if you suffer from anxiety it could make things worse,” says strength coach Gregg Marsh. “If you think you need them, consult your doctor first.”

How Much Should I Take?

Follow the instructions on the bottle, but be careful if you’re planning to use them over a long period of time. “Take them on a rotation cycle of 14 days on 14 days off for only two cycles every eight weeks,” advises Marsh.

When Should I Take Them?

Most fat burners contain caffeine and will make you jittery, so taking them in the morning is probably best. “Never take fat burners after 2pm because they affect sleep patterns,” says Marsh. Other than that, go with the recommendation on the bottle, but combine them with a structured exercise plan if you want to see tangible results. 

Do Fat Burners Have any Side Effects?

“Taking high doses of ephedrine can have serious effects, including palpitations, anxiety, insomnia, vomiting and dizziness,” says Bean. “While herbal alternatives are generally safer, you may get side effects with high doses – some can raise blood pressure or cause heart disturbances.”

Which Fat Burners are the Key Players?


Caffeine increases fat oxidation during rest and exercise, boosts the body's ability to metabolise fat (converting it to energy) and produces heat in your body to hike up your energy expenditure, called thermogenesis. Concentrated pill form is more manageable than caffeine via your daily coffee hits – to increase energy expenditure you need a high daily dose of 8mg per kg of bodyweight, that's equal to eight Starbucks short Americanos per day. Gulp.


If burning fat during a workout is your priority, first you need to mobilise it. L-carnitine is an amino acid that transports fatty acids into the mitochondria – our internal power plants – to produce energy. Take a single dose of 500-3,000mg before your workout to ensure that you transport the maximum amount of available fat for fuel during exercise. It’s especially useful if you’re training fasted or on a low-carb diet where fat oxidation is already maximised. However, as we said above, evidence for their effectiveness is thin. 

Green tea

One of the best natural fat burners around, green tea can give your metabolism a jolt. It’s also packed full of antioxidants and has been linked to the prevention of everything from heart disease to Alzheimer’s. Drink it instead of regular tea or diet soft drinks for a huge variety of health benefits.


Anyone training intensely is likely to be under some serious stress. The stress hormone cortisol, which is responsible for fat storage, is secreted in high amounts as a result, but phosphatidylserine blocks its secretion. This allows you to recover quicker, burn more fat and build more muscle. Take it after your workout or in the evening, especially if you’re training at high intensity or particularly prone to elevated stress levels.

6 of the Best Natural Fat Burners


Forget the miracle powders and potions. The best way to burn more fat is with blackcurrant extract, according to a study by the University of Chichester. When cyclists were tested at three intensities, there was a huge 27% rise at the highest intensity and 15% at the lowest. “Nothing else increases fat oxidation so substantially,” says the study’s author Mark Willem, a professor of exercise physiology. But why’s it so effective? “We observed a higher activation of an enzyme that transports fat into the powerhouse of the muscle, the mitochondria.”

How to work them into your diet Test subjects took 300mg tablets daily, so for the best results, do the same. The active ingredient is also found in other dark fruits and veg such as aubergines, plums and cherries, so eat those to burn more fat.


Researchers at Scripps Clinic in California found that eating just half a grapefruit before each meal can help you to lose weight, up to half a kilogram per week, even if you keep your diet exactly how it is now (assuming that you don’t eat junk food three times a day). The author of the study, Ken Fujioka, says that there is a key compound in grapefruits that helps to regulate insulin, a fat-storage hormone. “Anything that helps lower insulin can help people lose weight, and grapefruit seems to be one of those foods,” Fujioka says.

How to work them into your diet Peeling and segmenting is the most obvious way to get the goodness out of a grapefruit. Try cutting it into chunks and adding to a spinach salad or simply grab a spoon and eat as is, if you can handle the bitterness.


Eating a handful of almonds each day – alongside a healthy diet – is quick and simple way to burn fat, according to research published in the US International Journal Of Obesity. Participants in the study who ate almonds daily for six months found that they lost 18% of their body fat. Those who followed a diet with the exact same amount of calories and protein but swapped out almonds for an equal number of calories in complex carbohydrates (like bread) only lost 11% of their body fat.

How to work them into your diet They’re a perfect at-your-desk snack, although they can be quite addictive. Alternatively, chop them up and add them to your morning porridge.


An often forgotten fruit. A study by the University of Rio de Janeiro revealed that people who ate three pears a day consumed fewer calories each day and also lost more weight than those who didn’t. They’re very rich in fibre (with one pear packing in 15% of your daily recommended amount), so they’ll help you to feel fuller for longer and keep you from overeating.

How to work them into your diet Be sure to keep the skin on them as it holds most of the beneficial fibres. Pears make a great addition to a leafy salad, especially when combined with blue cheese.

Navy beans

Never heard of them? Well, they should figure in your diet if you’re looking to lose fat – a serving of navy beans contains nearly 20 grams of resistant starch. Researchers at the University of Colorado found that if you eat foods high in resistant starch levels just once a day you could burn 25% more fat than you would without them.

How to work them into your diet Try sautéing some shallots and garlic in olive oil, throw in a couple of cans of drained navy beans, mix it all up in a blender to purée.


Yes, chocolate. Hear us out. Dark chocolate – and other foods that are high in antioxidants – have been proven to help prevent the build up of fat cells in the body, a precursor to obesity and heart disease. This is according to research from the Taiwanese Journal Of Food Chemistry And Agriculture.

How to work them into your diet It’s chocolate. Do we need to tell you? Just try not to eat too much of it, kind of defeats the object. 

The Workouts

Without exercise, your fat-burning efforts would be futile. Here are three effective fat-burning training protocols to follow.


This stands for as many reps or rounds as possible, depending on the type of workout you’re doing. You do these workouts for time, so the emphasis is going as hard as you can for the prescribed period, with as little rest as possible. This creates a massive energy demand, which – you guessed it – torches loads of calories. Top personal trainer David Arnot suggests and AMRAP of ten kettlebell swings and six burpees in five minutes to start you off.


Short, vicious and fantastic for fat loss. These four-minute high-intensity interval workouts comprise eight rounds of 20 seconds’ work and ten seconds’ rest. And you can do them with almost any move that has an explosive element to them. “Not only does it increase fat burning, it’s also a great tool for building mental strength, because getting through Tabatas is a real challenge,” says trainer and former Marine Sean Lerwill. Try this Tabata workout to get you started with the protocol: 20 seconds of maximum-intensity rowing, followed by ten seconds of rest.


Fat Loss 4 is a workout protocol made up of four moves performed back to back in a circuit of just five minutes. You’ll do 30 seconds of an upper-body compound move, followed by a 15-second rest; 30 seconds of a lower-body compound move, with another 15-second rest; 30 seconds of a core move, with 15 seconds’ rest again; and finish with one minute 45 seconds of a high-intensity cardio exercise followed by a one-minute rest. “This works your entire body and massively raises your heart rate over a short period of time, which fires up you fat-burning metabolism during a session and keeps it working for hours afterwards too,” says personal trainer Will Girling. “Try this FL4 workout: four rounds of pull-ups, squats and Russian twists, with a row to finish.”

Our Experts

For more from Anita Bean, author of The Complete Guide To Sports Nutrition, visit For more from strength and conditioning coach, personal trainer and nutrition consultant Gregg Marsh, visit

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