My friend will find it easy to get enough carbohydrates/energy because most are plant based like bread, fruit and pastaMy friend will have a harder time consuming lipids. Without meat there will be less lipids in his diet. He could try olive oil and fatty plants like avocados to make sure he has enough for energy storage and balanced hormones.The hardest part for my friend will be protein. Most complete proteins are animals products. He will need to be creative with his choices. He should try quinoa, soy and other high protein plants, so that he can have enough proteins to do all the jobs they do (such as build tissue, fight infection and regulate chemical reactions).