Build muscle. This is counter-intuitive for most people, and especially for girls, who think they'll somehow end up "looking masculine" if they do so. But there are two sides to the Earth element in Chinese Medicine: fat and muscle. There's also two sides to insulin: building muscle, and accumulating fat.
Muscle mass elevates your basal metabolism. Other than counting calories, having muscle is like a cheat. It burns energy just be existing. Plus there's a myriad of health benefits to having strong muscles.
If you don't feel like getting into weight lifting, try hardcore yoga, or crossfit. Climbing. Water sports. Basically anything that simulates what your body is supposed to be doing instead of paying off debt all day in front of a screen.

Also, if you're 30+, accept that we humans (and women specially) are given a gift of Jing by nature that we will never be able to get back. Youth is meant to get us to reproduce, not look appealing forever. You were never your body, and decay and death is inevitable.

tl;dr: pick up heavy things and put them down repeatedly.