By Suzanne Goldenberg in Washington
In the days when he could "float like a butterfly and sting like a bee", Muhammad Ali sparred with the establishment by refusing to fight in the Vietnam war. In middle age, slowed and silenced by Parkinson's disease, he became a folk hero when he lit the torch for the 1996 Olympic games in Atlanta.
Now, aged 64, the evolution of the heavyweight champion has taken one more turn - into diet guru.
The heavyweight champion plans to introduce a line of reduced calorie snacks for young people, due to appear in American convenience stores early next year. The products from Goat - Greatest of All Time Food and Beverage - are intended to help fight America's youth obesity.