Weight Loss NHS
77,245 members41,306 posts

Fat or Muscle

I wish to lose weight and I am doing ok two stones in four months. I have cut my calorie intake knocked the beer and wine on the head and started cycling swimming and now joined a local gym. I am 62 so can't run now as it irritates my left knee and gives me back pain. Does any body know what goes first fat or muscle when I Exercise. Ultimately I would rather be heavier with a trimmer waistline no belly or man boobs than be really thinner but still flabby. One of the gym instructors says light repetitive exercise burns fat. One instructor says the body can turn muscle into energy easier than fat so will do this first. Articles say we burn fat and muscle at the same time.. Another says exercise involving weights builds muscle which then burns fat. Can anyone offer advice?

5 Replies

Hi. First let me point out, I am not a nutritionist, this is my opinion and is formed from reading lots of different views. Your body is a really clever piece of kit. If you do repetitive exercise, it will adapt to cope with the demand by building muscle. If you eat in a haphazard manner, sometimes missing a meal, it will adapt by laying down fat to get you through potential famine. Even though we are 21st century, our bodies are still evolved for Stone Age survival. Providing you take in less calories than you burn, you will lose weight, wether that is fat or muscle depends on what you are asking your body to achieve. Regular excercise + regular food = fat burn. Irregular excercise + irregular meals = muscle reduction.


Ditto above - what seems to work is not going full pelt- but sustained cardio work - so your body learns to use the fuel in your food intake as well as using some of the fat store.

The purists would say eat less calories than you consume ( which includes those you exercise away). I think you have to starve yourself to lose muscle - but clearly and sadly as we get older we lose some muscle mass....

The nutritionists would say - eat healthy within your calorie intake levels to lose weight.

You kind of have to find what works for you- my observation of the males including my OH - there is natural more muscle ratio to work with- so calories get burnt more easily....So keep up your programme of exercise and reps of lighter weights I to keep toned. Check out strength training - e.g. planks press up etc...there are loads of mini pod casts..around

Big congrats on weight loss - I would have thought you were doing fine - two stone in four months - well done:-)

1 like

Cheers Suzy that helps too 🚵🏿


Eeek! That's a tricky question! I think that scientifically, your body actually burns its small store of starch aka glycogen, first. This is stored in the muscles themselves for instant use and also in the liver. It's only about 2000 cals-worth (compare with 250,000 cals worth of fat we can store), so doesn't take too long to go. Not sure if the body tops it up from fat stores, though.

Anyway, I think whether you lose fat and/or muscle will to some extent depend on how many calories you consume, how active you are and what sort of exercise. As I understand it, a very low cal diet with no exercise will maximise the chance of losing muscle weight, so is not a good iea even if the numbers on the scales look good.

Exercise with weights will help to preserve muscle, as you are telling your body that muscle is needed - muscle is an expensive tissue, so the body will get by on the minimum needed for tasks. Tell it more is needed then it should build/preserve it, for as long as the demand is there.

Gentle aerobic exercise, walking, jogging, light cycling, low impact aerobic classes, should maximise fat burning. It's the sort of intensity you can keep up for a long time. Higher intenisty aerobic exercise, I think burns more of a mix of fat and muscle, but not too sure, as I don't have the enthusiasm for really going flat out myself.

I think overall if you eat properly and keep as active as possible, with an emphasis on using weight-bearing exercise, it will give you your best chance of maintaining your muscle mass.

1 like

That's really useful and seems to be in line with other advice. I have received . I think it was recieving conflicting statements from the trainers at the gym that seemed to contradict each other. In context howevever they were all making correct statements but without sufficient explanation. Thank you for that. There are so many factors which come to play which obviously influence what is going to happen. 🚴🏻👍


You may also like...