The study sits at the intersection of multiple fields and addresses a question that has been of interest for a long period of time to biologists working on organisms from yeast to mammals—namely what is the relationship between caloric intake, leanness and longevity?

  Does it describe a new discovery or a new methodology that's useful to others?  

The use of tissue-specific knockouts of the insulin receptor allowed us to separate out the important variables that could not be easily separated using conventional experimental approaches. 

  Could you summarize the significance of your paper in layman's terms?  

The most important finding from our studies was that low body fat content can improve longevity even in animals eating normal or increased amounts of food.  Also, we demonstrated that blocking insulin action in fat allows a mouse to eat all it wants, stay thin and live longer.

  How did you become involved in this research?  

We are interested in understanding insulin action in all tissues, and in particular, in fat, the relationship between insulin action and the accumulation of adipose tissue. 

C. Ronald Kahn, M.D.
President and Chairman of the Board, Joslin Clinic
Mary K. Iacocca Professor, Harvard Medical School
Boston, MA, USA