Should I take my son out of public school due to his weight?

My son used to be a very fit young man, but when he entered middle school they fed him foods that turned him severely obese. We tried everything to make him thin again like enrolling him in weight lifting classes, putting him on various diets, and even sending him to fat camp, but nothing worked! The only solution we can think of is taking him out of these horrible public schools and homeschooling him. Are there any other solutions that might work better?