Health association: In certain studies, most volunteers who used to eat meat have permanently excluded meat from their diets and now eat only vegetables and fruits  These volunteers suffered no ill effects and many even prefer the new regimen  So people who eat meat can change their diets to meatless ones and not suffer as a result
Critic: Participants in these studies were all favorably disposed to the substitution before they started, and even so, many of them failed to make a complete transition to a vegetarian diet
Most people, if told by their physicians to exclude meat from their diets and eat only vegetables and fruits, would succeed in doing so.