eating the same and exercising the same as I did five years ago, and my body is completely different." This is one of the most common things I hear, and it's not in your head, and it's not simply "getting older" in some vague, unexplainable way. There is real, specific physiology behind it — and understanding it is the first step to working with your body instead of fighting it.

If you're in your 40s and you've started feeling different, you're not imagining it. Maybe your sleep isn't as restorative as it used to be. You're gaining weight around your midsection despite eating the same way.