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Why muscle loss ends up as fat gain

We see many clients at Bodyscan who lose a lot of fat but who also lose a great deal of muscle too.

Sometimes so much that their body fat percentage actually goes up.

Look at the Bodyscan reports of these two clients who both did ‘biggest loser’-style diets with severely restricted calories: Nikhil, whose results are above, lost 4.7kg of muscle to his 4.9kg of fat, while Robert lost a whopping 10.8kg of muscle for 25.2kg of fat. Those big muscle losses do not bode well for keeping the fat off.

Indeed, loss of muscle is the reason why so many people who shed a lot of weight (see this article about DEXA and Oprah Winfrey) yo-yo back up again, and it highlights the importance of retaining your muscle mass when you embark on a fat loss regime.

Many people assume that when in a calorie deficit your body will turn first to its fat stores to make up the gap. But your body’s survival instinct takes an opposite view. Carrying muscle mass is calorie inefficient; big muscles burn a lot of calories even at rest. That’s why gaining muscle mass takes a lot of time, effort, heavy weights and loads of food.

Fat, on the other hand, is a great store of energy and helped ensure our ancestors’ survival when food was sparse and before there was convenience food within arm’s reach.

The need to survive and the expensive energy requirement of lean body mass is why your body quickly depletes your muscles – rather than your fat – when you reduce your calorie intake. The double whammy is that with lower muscle mass your body then burns fewer calories when at rest, so if you break your diet and simply go back to what you were eating before there’s now a bigger gap than there used to be between the calories you’re taking in and the calories you’re burning. Result – ballooning fat.

The statistics vary but a quick flick through a number of articles puts the number of people returning to their starting weight or above after a diet anywhere between two-thirds and 97%.

To retain your calorie-burning muscle, therefore, it’s a very good idea to add weight training to your programme. Unlike our big muscle-losers above, these two Bodyscan clients made resistance work a core part of their programmes: You can see from their Bodyscan reports that Katy reversed a fat gain/muscle loss to put on 3.2kg of muscle while losing 2.7kg of fat, and Rupert lost an incredible 14.3kg of fat while still building 2.2kg of muscle. The results speak for themselves.

In my experience as a personal trainer, success is wholly dependent on consistency. There is no point in any diet or exercise programme if you’re not going to stick to it, which is another reason why slashing calories and manic fitness schedules don’t work. In a couple of weeks you’ll be fed up and succumb to temptation. It’s better to plan for slower, more gradual fat loss by restricting calories just 10% or 20% below maintenance levels and an achievable exercise and gym schedule. (Note: if you’re gaining fat, you’re already eating above your maintenance calories. Check out our body composition calculator for an idea of your calorie requirement.)

If your programme has derailed, it’s probably time to get a new Bodyscan baseline. We’ll give you achievable targets and then measure your progress in 3-4 months’ time.

Author – Archie Williams
Bodyscan Consultant