I saw a tweet today claiming that
“Muscle was 3 times more efficient at burning calories than fat”.
It’s not more efficient, they do different jobs. It’s like saying an engine is better at burning petrol than a petrol can. But only if the engine is turned on!
When used, muscle does burn more calories than fat, because FAT DOESN’T BURN CALORIES – IT STORES THEM!
Muscles burn energy when used, fat stores unused energy
Muscle is largely constructed of protein fibres/filaments. These can slide over each other to make the overall muscle shorter which results in movement eg. The bicep muscle shortens to bend the arm at the elbow. Every time a muscle contracts, it requires energy to do so and therefore is burning calories.
The more muscle fibres you have, the more energy you will require to move them, but remember, only if you move them all! Bending your arm is not going to have your leg muscles burning calories!
Additionally, the harder the muscles have to work in moving, the more energy they will require. Obviously it will take more energy to lift a 100kg weight once than a 1kg weight once. It takes more energy to push a car than it does to push a pram. However, the harder each individual muscle has to work, the quicker it gets tired and unable to contract at all. So the more muscle there is, the less strain on each individual fibre, and the longer they can go on moving for.
Fat, by which I mean Adipose tissue, is the body’s method of storing unused energy derived from eating food. We get energy from everything we eat, but any that isn’t used is stored as fat.
And it just sits there. It doesn’t DO anything. so it doesn’t burn calories at all!
Back to our muscles, remember, they burn energy when we use them, and they burn more when they have to move more stuff around. Well, they have to move YOU around. So the heavier you are, the more energy it takes to move you around. Running, swimming, standing up, going upstairs, whatever it is you are doing, the more you weigh, the more energy it requires to move you.
It will therefore take more energy to walk a mile if you weigh 20stone than it will if you weigh 10stone.
So am I saying, put on weight if you want to burn more energy? No. If most of that 20stone is fat, then there is less muscle. It’s the muscles that move the limbs and help you walk down the road carrying that fat. So you will initially burn more calories because of the extra weight and subsequent strain on the muscles, but it won’t last very long because the muscles will tire quickly and you’ll have to stop.
If more of that weight is muscle, the strain of movement will be spread between more individual muscle fibres. Each one will be working less and will therefore tire more slowly – you will be able to move for longer and burn more calories. If you are eating correctly, those calories will come from fat meaning that your weight goes down, but not your muscle mass.
It’s often quoted that increasing your muscle mass will raise your metabolic rate so you burn more calories at rest, this is true, but largely because when we are at rest, we are still moving a bit, so we are still using the muscles and burning calories. The thing to remember though, is that the people with higher muscle mass and lower fat have it because they are active, and work in physically demanding jobs like building or farming, or exercise regularly and watch what they eat. The small rise in metabolic rate is a bonus but they are not sitting around all day watching the weight drop off because they’ve got “big guns”!
Picture a pound of lard (fat) and a pound of steak (muscle). Which one is using the most energy. Exactly, neither, they’re just sitting there. On a living creature the steak, or muscle, is moving, using energy; the fat is still just sitting there.
So, yes, increase your muscle mass, you’ll look better, feel better, and you will burn more calories as you go about your daily life, but it’s nowhere near the amount of calories you will burn actually building that muscle mass in the first place. So make the most of your muscles and use them!