Men should exercise BEFORE eating and women AFTER to burn the most fat, scientists reveal

January 16, 2016  16:29

Come January, many of us start pounding away on the treadmill in the hope we can melt our spare tyres, bingo wings and love handles. 

But new research has revealed that we may be able to burn more fat without actually doing more exercise.

Simply changing the timing of when we eat - whether before or after working out - means we could burn up to 22 per cent more fat, scientists claim. 

However, as with so many thing in life, they found the secret was vastly different between men and women.

While men burned more fat if they exercised before eating, it was the opposite for women. 

The experiment, featured on the BBC's Trust Me I'm A Doctor programme.

And today, one of the experts involved in the experiment told MailOnline that women who eat in the hour after they exercise could actually be blunting their fat-burning.

As part of the experiment, Dr Adam Collins, of the University of Surrey, recruited 30 volunteers.

These included 13 men and 17 women who did not normally do a lot of exercise - one man interviewed in the BBC programme said he had 'the fitness of a pork scratching'. 

For four weeks, they took part in three classes a week; a high intensity training class, Zumba and a spin class. 

They all consumed a drink before and after each class, but some were drinking a placebo with no calories, while others consumed a calorie-controlled carbohydrate drink.

This allowed Dr Collins to test the effects of eating carbohydrates before and after exercising. 

At the beginning and end of the experiment, they tested how much fat the volunteers were burning while at rest, along with their weight, waist circumference and blood sugar and blood fat levels. 

Dr Collins discovered that women burned more fat than men, and those who were taking carbohydrates before working out burned up to 22 per cent more fat.

Men, on the other hand, burned less fat overall, but those who were given carbohydrates after exercising burned 8 per cent more fat.

Therefore, the experiment showed men should eat after exercising to maximise fat-burning, while women should eat before.

This is because men are more muscly, and as carbohydrates are stored in muscles, this is their bodies' preferred fuel, Dr Collins told MailOnline.

If they eat before exercising, they have a store of carbohydrates available to their muscles, and they never make the 'big switch' to burning fat.

He said: 'Men get a better effect if they exercise fast [as in don't eat] as they're putting more stress on the muscle to burn more fuel, so the muscles burn more fat.'

Then, when they eat after exercising, they simply replace the carbohydrates that were used in the muscles. 

Women's bodies, on the other hand, are programmed to burn fat in order to conserve carbohydrates in the body.

He said: 'Women have more fat around hips, bums and tums, better release of fatty acids into the blood, hormonal differences which mean they can be better and more frugal at conserving glucose [sugar from carbohydrates] and burning fat.

'This is probably an evolutionary advantage to do with pregnancy. If women are better at managing their fuels they have glucose to spare for the foetus.'

For women, most fat-burning occurs in the three hours after they stop exercising.

Eating up to an hour and a half can actually stop a woman's body burning fat, he said. 

He said: 'By eating you're forcing the body to use carbohydrate, you could be blunting the whole shift to fat-burning.

'If women want to maximise their fat burning, they should wait at least 90 minutes after exercising before eating. 

'So don't have your breakfast straight after the gym.'

He says this idea of metabolic flexibility, being able to switch between burning glucose (carbohydrates) and fat, is the key to good health.

He told MailOnline: 'Most people who are obese are metabolically inflexible. They are constantly burning glucose and never make the switch to fat.

'Exercise is healthy because it stresses the muscles and forces them to become better at managing fuels, and switching between fuels.

'You can manage your food and nutrients better because yourve got the ability to switch between carbohydrate and fat.' 

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