Losing your pants

It appears that I would be wise to avoid shopping for my son till after school starts next year. It seems that the size of his waist the week before school started is now different, a mere 5 weeks into the school year. When we went shopping I measured his waist, handed him pants of that size and sent him off to try them on before buying them. They fit reasonably well, no pinching of tender parts, and no falling off his backside like a ghetto hood rat. Till now. They fall off his backside like a ghetto hood rat. There is a SIZABLE gap between his body and the pants. I asked if they fit when we bought them. "Yes mom. But the scale said 140. Then it said 135. Then.." "Did you lose weight or something?" "Yes mom." The conversation ensued about a belt. It is not something he likes to wear though, he prefers to just keep hiking up his pants. I suppose football tryouts, walking around school, to and from the bus stop, and not sitting in front of the tv all day like he did during the summer had an impact on his waistband. At least he hikes the pants up, and doesn't walk around losing them.