Don't get me wrong — exercising at any time is good for you. But evening activity may be particularly beneficial because many people's metabolism slows down toward the end of the day. Thirty minutes of aerobic activity before dinner increases your metabolic rate and may keep it elevated for another two or three hours, even after you've stopped moving. What that means for you: You're less likely to go back for seconds or thirds. Plus, it'll help you relax post meal so you won't be tempted by stress-induced grazing that can rack up calories, quickly.