Do boys care about weight

I'm asking because I took my kids shopping last week for back to school clothes and my son had to go up a size. He's 13. He put on weight over the summer and I said "You're getting chubby." He got quiet and ended up just letting me pick out his clothes. He's been acting weird since and if I hurt his feelings i feel bad. I didn't think that would hurt him. I honestly didn't think boys care as much about their weight as girls.