How does caloric intake reduction help extend human life?

You want to lose weight and keep it off And you want to live longer.

Severely restricting your caloric intake is a good way to accomplish your goals.

But let's face it. A severely restricted caloric intake really isn't your thing.

That's why scientists have been working to find a way for you to get the gain without the pain.

Take Dr. Leonard P. Guarente, M.I.T. biology professor, for instance. Studying yeast cells back in the mid '90s, Guarente may have found an answer. Guarente found that yeast cells lived longer on smaller amounts of food, so he started to manipulate the cells to find out how that extended lifespan. Guarente found that yeast cells with a reduced caloric intake given a particular gene lived even longer and when that gene was removed, the caloric reduction didn't work and the yeast cells died. The gene was called silent information regulator No. 2 - SIR2 for short.

While good news for yeast, not so good news for humans. We don't have SIR2. But we do have something close, called SIRT1.

Called sirtuins, both genes work by repairing DNA and suppressing certain genes. When sirtuins don't work, that might lead to diabetes and Alzheimer's, which occur due to genetic malfunction. Guarente believes that old age makes it harder for sirtuins to work and that reducing caloric intake may improve their function.