Don't worry.

This headline is not an internet scam or anything like a "magic diet pill" that promises the world but delivers nothing.

The following article is science's take on how to lose fat as fast as possible, without sacrificing muscle mass.

There's no pills here I promise!


As a lot of you know, losing fat can sometimes bring on muscle mass loss too. 

But the following is a formula to ensure fast fat loss without losing your hard earnt muscle!
Research into this suggests that the maximal rate that your fat stores can provide you energy is about 69.31 calories per kilogram of bodyweight per day (1).

Or for those of you who work in pounds (lbs) that's 31 calories per pound of fat.

So if you're carrying 8 kilograms of excess fat, then it's simply 8 x 69.31 which works out to be 554 calories.

This means your calorie deficit everyday can be as high as 554 calories, to ensure the fastest fat loss possible WITHOUT sacrificing muscle mass.

And just like our total daily energy expenditures and basal metabolic rates, which are all estimates, so is this.

But I will point out that you should REDUCE your deficit if you find your performance is lacking in the weights room - as the estimate hasn't been beneficial here.

It's just a starting point that you can work with, maybe try by decreasing the deficit by 150 calories and trying again. 

Even at the 30 day mark, you should be noticing the difference. 


Again, whilst it's hard to have a "one size fits all" approach to numbers and fat loss, it's generally accepted that roughly a deficit of 7,700 calories is required to lose 1 kilogram of fat (2). 


Anyone on a diet knows that when you keep dieting, after a while, fat loss stalls.

As you diet, maintenance requirements drop because of the mass you've lost. Your metabolic rate adapts and goes down, obviously because the fuel to run your car is less because your car is getting smaller.

So after a while, you will have to recalculate your total daily energy expenditure, relook at your lean body mass (what fat percentage you are) and continue with this fast fat loss formula to ensure weight loss continues to occur.

Nothing get's easier, it only get's harder, but just keep calculating and keep moving - don't ever forget why you started in the first place!


"Stay Fit, Stay Flexed!" 



(1) Alpert SS. A limit on the energy transfer rate from the human fat store in hypophagia. J Theor Biol. 2005 Mar 7;233(1):1-13.

(2) Hall KD. What is the required energy deficit per unit weight loss? Int J Obes (Lond). Mar 2008;32(3):573-576. Published online Sep 11, 2007. doi: 10.1038/sj.ijo.0803720