Conditioning! This has to be it the others seem unrelated. Terribly worded question.
Answer:
Purging by self-induced vomiting can cause a few noticeable effects in the face and mouth, including: Tooth decay: Strong stomach acids may break down the gums and tooth enamel over time, which could lead to tooth sensitivity and cavities. Raspy voice: The stomach acid in vomit may damage the vocal cords.
This depends on the person, as people have different needs and athletes need more calories then normal scholars. The average is about 1,600-2,100. But again it depends on the person, for example I can only eat about 1,500 calories a day, despite the fact I'm an athlete, my friend however can eat about 2,500. If this is for personal use I would recommend consulting a doctor or trusted adult before you go on a diet.
Hope this helps :)