One of the main culprits of middle age weight gain is that we lose muscle as we age.
So even if you’re the exact weight you were, when you were 20, you have a lower % of muscle than you did then.
Muscle is hugely important – especially to our metabolism.
The calories we eat,create energy for our bodies to use.
But because our muscles are literally shrinking, they can’t burn those calories efficiently anymore.
The unused calories end up as fat.
Source: How to Lose Weight & Get Healthy even if You’re Lazy by Becky Clark