Unless you're medically disabled it can be done. Simple life choices example, instead of driving to the local corner store, walk instead. Or instead of drinking a 6 pack of beer, drink 1-2 and drink water, orange juice, apple juice, etc. simple changes like that is all it takes to just get started. Now if your after a 6 pack of abs and wanna look like a body builder that's a whole different ball game.
