I am 21, I gain 20 KGS in 4 years. I consult doctor and diagnosed for thyroid but results was negative. I ate junk food for last 2 years daily. And my problem is gas trouble and body temperature is quite high when I did not go to bathroom and bowel movement is changing. Some time there is severe pain in abdomen. Body is also dehydrated in these conditions. Hot air comes from nose and mouth.