How to tell if you gained muscle or body fat

So, you have gained some weight and you are wondering if you’ve gained muscle or body fat? Well, that’s a pretty valid question. And we have some answers for you. We’ll describe how to understand the difference between muscle gain and body fat gain.

You know that your scale can’t distinguish between muscle mass, fat, bone, internal organs and water. The scale cannot distinguish even a living being from a non-living object. So it by itself cannot tell you what type of weight gain have you experienced. So you’ll need to consider some other things.


If you are consistently exercising and you notice a small and slow weight gain, you are probably gaining muscle. Your muscles are improving and growing in size, growing new fibers and repairing the damaged during the exercise ones. But if you do not exercise and notice a weight gain, you are probably gaining body fat.


If you have experienced a small weight gain but you notice that your clothes are becoming looser, this certainly means that you are gaining muscle because muscles take more place than fat. Also, rapid weight gain (or a significant one) means you’ve put on some body gat.

A simple testing method

If you want to test if you’ve gained muscle mass or body fat, here is how to do it yourself.
Start by stepping on a scale to figure out your weight.
Then measure your body fat – the easiest way if with a body caliper.
Afterwards, multiply the weight measurement by the measured body fat percentage to find out how much body fat you have. Record your answers for future references.

Then subtract the amount of fat from the original weight measurement from the first step.
This will give you the amount of lean weight of your body. Remember, lean weight consists of muscle mass, bones, organs, etc.
After about 3 to 6 weeks perform this process of measurement again and compare the results.
This will show you whether you’ve gained fat – if your body fat percentage has increased – or muscle – if your lean weight has increased.

Hydrostatic weighing

Hydrostatic weighing is the gold standard for testing what the body composition is and is thought to be the most accurate way of determining what is your body fat percentage. The test determines the body fat percentage by testing how heavy are you in water. First you’ll be weighted on dry land and then in a tank of water.

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