Why is it easier for some people to lose fat and stay lean and others struggle? The answer is because of muscle type (slow twitch and fast twitch) distribution and body type (ectomorph, mesomorph, endomorph). \
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.
Another factor that determines leanness vs. overweight is body type. There are three distinct body types. ectomorph, mesomorph and endomorph. The ectomorph person is skinny and has small muscle mass. These are folks are best at long enduring activities like running, cycling, swimming. They have a tough time putting on fat and muscle. Because they have so much oxidative properties they are burning too much to sustain large quantities of muscle. These guys in bodybuilding circles are known as the hard gainer. On the other end of the spectrum are the endomorphs these folks are the ones that have a tough time losing body fat. They can carry large amounts of muscle tissue. They are mostly made up of fast twitch fibers. They don't have the oxidative properties to burn off high percentages of fat. They end up storing large quantities of fat. They will always struggle with their body fat.
The mesomorphic body build has the best of both worlds. They usually have an equal distribution of fast twitch and slow twitch fibers. They are the gifted ones. These folks have a nice distribution of fast twitch and slow twitch fibers. Many mesomorphs have well defined muscle. These lucky folks don't even have to train to look good. Many guys that I know in bodybuilding hardly train at all, they just have great genetics and are naturally muscular. Women who are mesomorphs tend are well defined and in some cases some women don't like the muscular look. But muscle keeps the body looking young and strong.
We all have different characteristics of the different body types. There are some people that might be in the middle of the ecto and meso body type. And people that in the middle of the meso and endo. Overall, body type and fiber type distribution dictates how much fat you can metabolize and how much muscle you can develop. Not everyone can develop defined massive muscles and not everyone can run a marathon. Knowing what you are will help you know how to train appropriately. I design programs for all body types. If you are interested in knowing what exercise sequence would be best for you please visit www.darylconant.com and send me your question (contact us). I would be more than happy to help you.
tags: body fat, muscle, steroids, anabolic effect, ectomorph, endomorph, mesomorph, health, vince gironda, joe weider, strength training.