A vegetarian food is a food, which does not contain animal flesh and meats. All the food material in this diet is derived from plant products.
This kind of diet lacks meat, which are a good source of proteins. So, in this case, the meat can be replaced by other food products, which provide similar amount nutrients as the meat do.
In a vegan diet, beans, butter and dark leafy vegetables can make a complete diet for a day. So, Jamie should take almost 1/2 cup or beans or pulses along with 2 table spoons of butter and 1 cup of any dark leafy vegetable for a single diet.