People will think that because genes play a role in something, they determine everything. We see, again and again, people saying, “It’s all genetic. I can’t do anything about it.” That’s nonsense. To say that something has a genetic component does not make it unchangeable.

- Eric Lander, leader of the Human Genome Project.
Don't blame your genes for your fatness.  It is your lifestyle that determines your body composition, not your genes.