I lost a lot of pounds one summer when I used to live in a school that served vegetarian food only for religious reasons. The reason I lost almost 30 to 40 pounds is I cooked my own food which was vegetarian, but probably didn't use the high sugar the cafeteria used to compensate for the lack of meat. A lot of it is simple energy in and energy out. People honestly really underestimate their energy in and overestimate their energy out.