The Something Awful forum has a "Goons in Platoons" board for discussions on the military, police, and emergency services life. The "Let's Talk About Idiots!" thread is very popular, and is one of the best ways to get a true view of how stupid soldiers can be. Firsthand accounts from soldiers all over the world (mostly the US) indicates that yes, overweight and at least chubby soldiers abound. Some guys manage to get fat enough to be visibly obese, even people who are shipped to war zones (though the really overweight ones usually stay behind at the base instead of actually leaving the wire).