The science behind faster fat loss




Fat loss occurs when your body is in a caloric deficit: i.e. you are consuming less energy than you burn, forcing your body to dip into fat stores to sustain itself. This can be done one of two ways: you can eat less than the energy disbursed by your basal metabolic rate (read: the amount of calories needed to maintain your body at rest) from the comfort of your couch, or you eat at your resting metabolic rate and create the deficit through exercise.

It makes sense, then, that faster fat loss combines a bit of the two: train hard while eating at a slight calorie deficit.

We asked Pettersson to show us how:

Here is a simple way to work out how to run your body at a 10 per cent caloric deficit.

Your basal metabolic rate = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years)

» Tip: cheat and use one of the host of BMR calculators available online.

Add 300 calories (to cover any training done that day).

Multiply by 0.9, giving you 90 per cent of the daily need, thus creating the 10 per cent deficit.

You can vary your deficit according to the pace you wish to lose fat. However, I never recommend a female go below 1200 calories a day.

» Small deficit: metabolic rate + 300 calories x 0.9 = 10% deficit (average weekly fat loss: 500 grams)

» Moderate deficit: metabolic rate + 300 calories x 0.8 = 20% deficit (average weekly fat loss: 1kg)

» Large deficit : metabolic rate + 300 calories x 0.7 = 30% deficit (average weekly fat loss: 1kg +)

When you’re specifically aiming to lose fat, don’t expect to see an increase in muscle mass: it’s very common to actually see a small amount of muscle atrophy (loss) due to the consistent caloric deficit.

» To maintain body fat mass: you’ll need to be right on the money when it comes to energy input versus output; so you’ll want to eat your metabolic rate plus 300 to 500 calories, depending on your training duration and intensity. I usually go slightly over on my calories to ensure there is no muscle atrophy when I’m aiming to maintain my current body fat mass.

Grab the September 2017 edition for the full story on how to fast-track your lean body results.