"At 30. By this age, you may notice that losing weight isn’t as easy as it used to be. This happens because as you get older, you move less. If you aren’t physically active, you could lose 3% to 5% of muscle mass each decade.
At 40. Your body starts to lose muscle mass naturally. This process is called sarcopenia. Even if you’re active, your body will still lose some muscle. During this time, fat will start to form instead of muscle. This also slows down your metabolism, depending on how much muscle mass you’ve lost."
Fucked.