 Our metabolism slows as we get older. Of course, as we get older, our body loses the collagen in our system. That starts in our mid-20s, but then, of course, by the time we get up into our 50s, 60s, 70s, that's really when we notice the loss of collagen. Our skin becomes wrinkled. Our hair becomes more brittle. Our fingernails more brittle. And we tend to become more fat and less muscle. And, of course, as we lose that muscle, then our metabolism slows, which gets us to become more fat. So it makes it harder for us to lose weight.