I'm not sure but..Fruits and vegetables are pretty low in calories mostly.
Calorie Counter - Fruit
Do you really think that they consume as much calories as meat eaters?
Calories in Steak
Foods highest in Calories in Pork Products
Calories in Chicken, Breast, Meat Only
Calories in Chicken, Drumstick
Calories in a Shrimp - Shrimp Calories
Heres some information on calories in meat for comparison.