Originally published on ETOnline.com. Personal trainer Chris Powell and his wife Heidi Powell are back for their fourth season of?Extreme Weight Loss, and this time they are joined by Doctor Holly Wyatt, a nutritional expert. Extreme Weight Loss?is a documentary... I’m thankful for Dr. Kashif Alvi. This miracle-worker relieved me from the excruciating pain of that darn kidney stone. So thankful for him and for modern medicine.