Though eating a lot but still thin

Though eating a lot but still thin - Wonder it, but every day eating a lot, but still thin and weight is not up-rise. Not that our friends who only eat a little skinny. This can be influenced by several factors, what are the factors? Here as in the following reports from eHow.

Gen

If your parents or your grandparents every skinny, so you can go too thin due to hereditary factors. This is caused because the metabolism gives a large role to someone who eats a lot but still skinny. While metabolism is influenced by genes. Some people are created with a high metabolism, so despite eating a lot, the body will not gain weight.

Diet
Another reason why eating a lot of fat the body can not make is because most nutritious food consumption were high. So even though there is a friend who ate burgers in bulk, maybe he also consume vegetables and fruit salad before.

Activity
Slim body shape can also be determined by the activities carried out daily. The more moves, the more the body burns calories. So even if a person eats more, his body remains thin, as the activity is quite solid.

Sick

Thin does not always mean healthy. There are also people who eat a lot but still thin because of illness or suffer from eating disorders such as bulimia.

That's the reason why there are some people eat a lot but still skinny. Even so, it is not necessarily the kind of person that always has a healthy body condition is not it?