Gaining Weight When You're Just Starting to Workout

This happens to me every time when I'm trying to get back into exercising again after a long hiatus. For the first couple weeks to a month, I either gain weight or my weight stays the same, even if I'm working out like a madman.

For me, it's due to gaining muscle mass, which weighs more than the fat I might be burning. As I gain more muscle mass, I'll reach a critical point where the amount of muscle I have and the aerobic exercises I'm performing will just start to melt the weight right off of me. This is because muscle uses a great deal more energy just to maintain itself, and when you have enough muscle it'll start using up your fat stores and excess tissues. Because to be honest, muscles aren't too picky about where they're getting their energy from, be it from your protein stores (muscle) or your fat stores.

Which brings me to another point, whether you're body burns fat or muscle depends on the amount of oxygen you're consuming, which depends on the exercises that you're doing. The fat burning stage requires you to reach a deficit in the amount of oxygen you have available to your muscles, you're muscles need to run out of oxygen before they'll switch to fat burning.

That's why they say there's a fat burning zone, it's when you're working hard but your heart rate isn't too high and you're not breathing too hard. When you're in that zone, you're not actually taking in enough oxygen because you're heart rate isn't fast enough to carry oxygenated blood to your muscles in the amount you need to maintain protein metabolism. So you're body switches to fat burning. You can tell when you reach that point because you'll have more energy, all of a sudden you feel like you can workout longer and harder.

It takes longer for runners to reach the fat burning stage, which they call their second wind. You're arms and legs are pumping, helping your heart get that blood loaded down with oxygen to your muscles, and you're feeling that good burn in your lungs as they're sucking in as much air as fast as possible. (Sprinters are different, the explosive amounts of force and energy involved in sprinting utilizes fast twitch muscles versus the slow twitch muscles that other runners use.)

That's why it's easier to get those pretty defined abs and deltoids when you mainly weight lift, your body's working hard but your heart and lungs aren't racing, so you burn fat and your muscles pop.

I prefer aerobics and running. The whole lungs burning and heart pumping hard, yeah that's my cake. But my body is naturally made up of more fast twitch muscles which work well anaerobically, which means I gain muscle mass easily (bulk up) and I'm a good sprinter. So instead I focus on building up my endurance/stamina aerobically because it's harder for me. Who doesn't like a challenge?

With aerobic exercise my body focuses on protein metabolism through the breakdown of muscle, so I stay trimmer while still keeping a nice fat layer.