Weightlifting has many benefits. The obvious one is increase of muscle mass. Most people don’t realize the real work of the body is not during the workout, but after. In a really good workout with weights, you work the muscles to failure. That means actually killing off many off the fibers and tissue. Over the course of the next few days, the body works to repair the muscle, and make it better. This is why you alternate body sections — the idea is to give any given muscle a few days to recuperate before killing it off again. (Note that many people don’t work out this way, you still get plenty of benefit even if you don’t work all the way to muscle failure.) The re-creation of the muscle is what burns the calories, it takes a lot of work and energy.
Likewise, when you suffer any kind of injury, your body needs energy to recuperate and rebuild it’s systems. Many of us have lost those few key pounds when we have a virus. When you run a fever, your body is literally cooking itself. Fighting disease takes energy, and recuperating afterwards does also.
Blood loss is one such injury. When you give blood, your body needs time to recuperate. That’s why you’re supposed to take it easy for a few days afterwards, your body needs time to rebuild. This logically leads to an obvious weight-loss strategy.
Donating blood five times a year not only is the right thing to do (go here for more info, or just get in touch with me directly), you can lose weight while doing it! Now that’s a win-win! And if you can’t give blood, at least get sick every so often.
(P.S. No, I’m not serious about this as a real weight-loss strategy. You really should give blood though.)