Scientists are giving us even more reasons to watch our diet. A year ago, they found that there really is such a thing as a "fat gene", a part of our DNA that promotes weight gain.

Last March, they found three more of these fat genes. Now they've isolated two more. For the curious, the genes are called the MC4R and FTO genes.

Scientists have also found that a combination of these two genes promote even more weight gain than if you just have one. Gives "packing in the pounds" a whole new meaning.

The study found that having variants of the MC4R gene could lead to as much as 1.5 kg in weight gain, while the FTO gene can lead to as much as 3 kg. As if that wasn't enough, it was found that having both genes could get you up to 3.8 kg of extra weight.

It doesn't end there either. They also found that the effects of the MC4R gene is doubled. Between four to seven, kids who have the gene almost exclusively increase in weight by gaining fat tissue, and will not gain any muscle or solid tissues.

As far as the study goes though, the research still recommends a healthy lifestyle and diet to control weight. Which means you should take some time off Grand Theft Auto 4 to do more than just eat, drink, and go to the bathroom. Stretch your legs a bit.