Did you know, that when you walk a force between three to six times your body weight is placed through your knees?  That comes out to roughly 4 pounds of pressure for every 1 pound of body weight that you carry.  It has been shown that for every 11 pounds of weight lost, the risk of developing significant knee osteoarthritis drops by >50%.  Think of it this way; with an 11 pound weight loss, each knee would have to carry about 48,000 pounds less in compressive load per mile walked! It goes to show you that the decision to eat healthy, does carry a lot of weight.