The investigators are trying to understand how genetic variations cause differences in people's ability to store fat and wish to test the hypothesis that individuals carrying different genetic variations have different abilities to store fat under the skin as subcutaneous fat tissue. This could lead to an improved understanding of subcutaneous fat storage. It is very unlikely that the rising numbers of people becoming overweight or obese as they age will be substantially reversed, therefore the study's findings could be important in identifying how to reduce the risk of disease caused by obesity.