I have messed up my metabolism with trying every diet out there. 40y/o female 5'6" 200 lbs. how can i speed it back up & have energy to workout?

Viscious circle: You need energy to work out, but you feel too tired to exercise! start slowly. Rather than going to the gym for a spinning class, start by walking around the block. Tomorrow, try two blocks. Keep on going until you are walking a mile a day. When that becomes routine, extend it to a mile-and-a-half. If weather is an issue, know that many shopping malls open early for "mall walking." this works!