Eli5: I recently realized fat is stored energy. If thats the case, then how do bodybuilders manage if they’ve got a lot of muscle and hardly any fat.


Eli5: I recently realized fat is stored energy. If thats the case, then how do bodybuilders manage if they’ve got a lot of muscle and hardly any fat.

In: Biology

My understanding is that, diet-wise, they “bulk” to build muscle, then “cut” to eliminate visible fat. For physique competitors, they are physically at their weakest at showtime. They then take a break (ideally) and repeat the process for the next show.

Because they work out and burn the energy they eat. Our bodies choose to burn fat for energy before muscle tissue so they keep the muscle they are building and burn the fat if they do get flabby in the offseason

Manage to… what? Continue living? I assume so.

Fat is stored energy that is tapped *when you have no readily available energy*. If you eat regularly, your body defaults to what it can get from that food and burns fat when it needs additional energy.

Bodybuilders are not completely fat-free, either — they just push body fat levels down to single-digits through harsh dieting prior to competition, and tend to maintain higher levels (though still leaner than average) when training/living otherwise.

You are onto something, though. Having too *little* body fat is quite bad for you. The extreme lows that bodybuilders pursue can be dangerous, damaging organs at low enough fat percentages.

First, There are many sources of energy in your body and “metabolic pathways” or ways your body takes something that isn’t usable and turns it into a usable fuel source.

1) Sugars – These are the easiest to break down. The body uses these first.

2) Fats – These are harder to burn than sugars but easier than protein so your body tries to use these second. Burning fat instead of sugar is called ketosis and is the idea behind the keto diet. That’s a whole other discussion.

3) Protein – The body can break down protein for energy but it takes more work so it’s generally the last thing to be used. Eventually the body will break down muscles, this is very bad but better than dying.

Second, The body is going to burn what’s in the digestive tract first. If they’re consuming enough calories in a given period of time their fat reserves will remain largely untouched.

Third, a body builder will at no time be “fat” but they fluctuate. At competitions they might get down to 2-5% body fat but outside of intentionally reducing their body fat percentage for the competition they generally have more fat. There’s multiple reasons, one being the energy factors you mention and another being that it’s really unhealthy to run in low single digits for body fat.

To summarize, they eat enough, there’s other places they get energy than fat if they don’t eat enough, and they’re generally still at a low but reasonable body fat percentage.

Your body stores energy is a variety of way, mostly in the form of glycogen in your muscles and liver. Fat stored in your adipose tissue is your body saving energy for later incase these stores run out. Body builders can get by perfectly well without body fat