FORT STEWART, Ga. — When Staff Sgt. Chris Brown headed into the swamplands of Georgia for a military training exercise early this spring, he found himself missing his time in Iraq and Afghanistan — and the relative comforts he had enjoyed there at the height of both wars.

Without running water, he now had to bathe with baby wipes and shave without a mirror. He had no idea how his favorite basketball team, the Golden State Warriors, was faring in the playoffs. And the food was so bad that he relied on peanut butter crackers and lost 10 pounds.

“When we were out there, they tasted amazing,” said Sergeant Brown, who went to the gym twice a day when he was overseas to make sure he did not put on too much weight from the dining hall and its honey buns and muffins.

While some American military personnel, in particular Special Operations forces and a number of Marine and conventional Army units, operated out of small, spartan outposts in Iraq and Afghanistan, the bulk of Army troops lived on bases that had running water, electricity and housing units. Some larger bases even had wireless internet, televisions, gyms and coffee shops. Civilian contractors guarded the bases, cooked meals and transported ammunition, food and fuel.