, spivonious wrote

This doesn't have to mean going to a gym.

Actually, working out with weights is a very efficient way of increasing metabolic rate, and hence burning more calories 24/7, and twice a week (perhaps 3 times if you find that you really enjoy it) is usually more than enough for the average person. 

Forget any illusions about it making you into another Arnold - that ain't happening - but improved muscle tone and strength, has significant health benefits for sedentary workers.