My first post here so hello everyone 
My son and stepson are both 16 and have just finished their GCSE's. My son found the exams stressful and he gained a substantial amount of weight during the gcse process about two stone, I know it's bad but eating was his way of coping with stress.
My stepson has been teasing my son by taking pictures of him on snapchat with fake cartoon food in his hands. He has also made quite horrible comments saying my son has a pot belly and should go out running. My stepson is very slim as he does sport professionally. We went shopping for holiday clothes and he was bragging about having a waist 10 inches smaller than my son etc. My son responds by comments about dss acne which got worst because of stress and hot weather and by calling him lanky.
I know people will say it is two teenagers being little shits to each other and they might have a point but it is always stepson who starts the name calling and I have told him so has his dad and we have confiscated the phone.
I am worried that when we go on holiday in around 3 weeks time it will get worse as ds will be in swimming shorts. He already feels self conscious and I have put him on a diet and exercise program.