My son is also 16, and also a salt waster. We address the salt wasting by always keeping a bag of well salted potato chips for him to snack on (he likes salt and vinegar). He's working w/ landscapers this summer and doing pretty well. He seems to sense when he's in need of salt. He was also a "chubby" kid, and when he hit puberty, boy did he slim down. If I didn't watch him eat, I wouldn't believe he did. He's doing very well.