Monday 12 November 2012

Weight Loss vs Fat Loss




I pitched up at Surrey Sports Park yesterday to do my swim after 400m to be stopped by a man about 50 years old who asked, ‘how do you get a body like that? Not from swimming, right?’ To which I smiled. After checking he wasn’t chatting me up - he had a wife and kids (apparently) - and before I could impart any of my wisdom on him he told me he’d already lost a couple of stone, but recognised he didn’t have the bodyshape he wanted.

Being a polite kind of guy I congratulated him on dropping a couple of stone because we all know losing weight is tough. I didn’t tell him I was a trainer first of all, but agreed I’d spent a fair amount of time in the gym over the years, but in truth I haven’t done any formal gym training for a while. I then asked him what he did to lose the weight. He told me I just ate less and exercised more. 

This highlighted a really common misconception I hear all the time. There is a huge difference between weight loss and fat loss. It is actually possible to lose weight and still be fat. This is why the BMI (body mass index) is a bit misleading. And this is why the guy wasn’t too pleased with how he looked.

To break this down a little you need to know a couple of things. Firstly, the BMI makes no inference to body composition. It is total bodyweight. This includes both body fat (the flabby bits on the back of your arms or belly), lean mass (the metabolically active tissues i.e. muscle). Separating the two is important.

The trouble is eating less and moving more for the most will mean you lose weight and sometimes unfortunately this includes muscle. To me if you are genuinely overweight this is a good place to start. If there was a benefit to the BMI this is it. If you outside of a ‘safe’ weight (overweight or above...) weight is a relevant measure. Whilst weight doesn’t kill you per se, it is a good indicator of how healthy you are, particularly in non-athletic people.

Let’s not overcomplicate this. If you are heavy and don’t exercise you can just get moving and eat less. It’s simple thermodynamics, not easy, but simple.

However, this has some shortfalls. If you choose the wrong type of exercise or create too much of a calorie deficit with food, like I said, you might lose muscle too. This is not good. Muscle is metabolically active and is also what makes your not so firm bits look ‘toned’.

Therefore, just to clarify if you want to look more like me (hahhahaha) you need to preserve muscle and burn fat, not lose weight.