I went to a lot of chess tournaments as a kid, and I never noticed this phenomenon. I can only name a few GMs that were on the fat side, though.
Not eating is, I think, part of it. Usually a tournament with 40/2+1 time control spaces rounds 6.5 hours apart, and a single round could take close to 6 hours. A full 6-hour game is unusual, but 4 hours of only staring at the board, drinking water, and walking around looking at other games is normal.
I can't remember if food was even allowed at the table; I only remember one time seeing food: at a scholastic tournament, my opponent ate a clementine before the match. Technically, 40/2+1 gives you enough time to drive to Taco Bell (even on your move), but I've never heard of anyone doing it.
If you ask my mom, she'll remember seeing kids from out-of-state wandering between rounds: "have you eaten lunch?" "No...?" like they hadn't even been thinking about it. Just total space cadet stuff, sometimes. (she drove the kid to McD's, I think)
Not eating is, I think, part of it. Usually a tournament with 40/2+1 time control spaces rounds 6.5 hours apart, and a single round could take close to 6 hours. A full 6-hour game is unusual, but 4 hours of only staring at the board, drinking water, and walking around looking at other games is normal.
I can't remember if food was even allowed at the table; I only remember one time seeing food: at a scholastic tournament, my opponent ate a clementine before the match. Technically, 40/2+1 gives you enough time to drive to Taco Bell (even on your move), but I've never heard of anyone doing it.
If you ask my mom, she'll remember seeing kids from out-of-state wandering between rounds: "have you eaten lunch?" "No...?" like they hadn't even been thinking about it. Just total space cadet stuff, sometimes. (she drove the kid to McD's, I think)