Ask the experts: Difference between fat and muscle

Healthy Food Guide nutritionist Claire Turnbull explains the difference between fat and muscle and whether one can transform into the other.

Q: “I’ve been going to the gym and I’ve actually put on weight. Is this my fat turning to muscle?”

Jeremy, via email

A: HFG nutritionist Claire Turnbull responds:

The most important things to understand about fat and muscle are:

• Fat is fat and muscle is muscle. They are separate things and can’t be converted from one to the other.
• A kilo is a kilo, whatever it is made up of. But muscle is more dense than fat, which means it takes up less space. So if you’re gaining muscle and losing fat, you’ll look slimmer, even if that’s not reflected by the scales.

If you start going to the gym and you’re putting on weight while eating the same amount of food, it’s likely to be because you are building muscle but not burning fat. If your weight stays the same, but you notice you look and feel slimmer, you’ve probably lost fat and gained muscle in similar proportions.

To reduce fat, you need to be having a healthy, balanced diet and burning lots of kilojoules during exercise. The aim being to burn more kilojoules each day than you are eating overall.

To gain muscle at the same time, you need to include some resistance exercise (weight-bearing exercise) in your workout and include a small amount of protein-rich food as well as carbohydrate in your meals and snacks before and after this exercise.