Why is it easier for some people to lose fat and stay lean and others struggle? The answer is because of muscle type distribution and body type ...
There are two types of muscle fiber, slow twitch and fast twitch. Slow twitch fibers are oxidative. Meaning that they consume a large concentration of myoglobin and can produce long lasting endurance properties. Fast twitch are non-oxidative and are designed for short burst of powerful energy. These are the fibers that are responsible for increased size of muscle. We all have both types of slow and fast twitch fibers. However, the distribution is different among everyone. For example, a person might have a higher concentration of fast twitch fibers in their legs and have a higher concentration of slow twitch fibers in their upper body. This person would tend gain more body fat on the legs than the upper body. People who have a hard time trying to put on weight could be higher in slow twitch fibers throughout the body. They are great at endurance activities because of the oxidative properties but not good at building size of the muscle.
