How do you know what foods your kids can't tolerate?
In our case, it couldn't have been easier to diagnose DD with lactose intolerance (but certainly wasn't easy to experience). DW had a health issue early on that forced a switch to formula for DD. Immediately after switching, we observed that her stomach was bloated and hard, and she had stopped defecating.
We switched her out to one of those formulas that are advertised as easy to digest (lactose free and every protein broken down to smaller chains), and the problem was relieved. Those formulas are rather expensive, though, so later on we tried one that was just lactose free, and that worked out fine.
Of course, we already knew DW was lactose intolerant, so that helped.
Over the years since, we've been able to bust our DD for drinking regular milk at a friend's house, or at school, because the bloating and constipation issues show up again. The cause and effect couldn't be more clear.
