U.S. Army troops in Iraq cannot meet the local women, nor can they have any alcoholic beverages. This creates a bit of a morale problem. Some troops manage to secure a little sex and booze on the side, but most just fall back on other stress relievers, like video games, and food. That last bit of comfort comes at a price; additional weight. Since most of the army troops in Iraq are in support roles, they don't have to worry about maintaining their "fighting weight," and some bulk up a bit, without fear of life-threatening consequences.
You cannot be fat in the U.S. Army, not if you want to get promoted or, if you bulk up too much, for too long, even stay in. Not willing to lose valuable troops to an understandable side-effect of life in a combat zone, the army has given waivers for troops having calorie control problems in Iraq. They can still apply for promotions they are otherwise eligible for, and have six months to loose the battlefield fat once they get back.
The chow in Iraq is actually quite good, and plentiful. Combat troops get to run around a lot, and burn it off. The grunts also spend days outside the wire, subsisting on MREs, which are not known to fatten you up. But for the guys and gals back at the bases, comfort food has become a curse.