My battle to keep weight on

[Tiggeroo]

my 15yo son, that is. He is right now at his highest weight of like 119lbs. BUt cross-country season has just begun. At 5'5'' he dropped to 107lbs last year. You can see every bone. I also think it would effect his running ability. He eats pasta almost every night during running season. But he skimps on breakfast and lunch. The reason for the lunch is that his practice is at 2:00 and he feels sick if he eats too close to this. On race day he will eat nothing either.
His twin brother has the opposite problem, and during wrestling season is always trying to keep the weight down.