Fat / Protein Sources for (mostly) Vegetarian & Possibly lactose intolerant Child
Some background -
We have a 2 year old who eats mostly vegetarian. He may only have a source of animal protein once a week (and that's usually if we are just home from work late and need to grab food on the way...or are visiting relatives - we don't buy animal proteins during normal grocery shopping).
He's on the skinny side as is (lower % weight), but so far we have seen no side affects insomuch as his weight or development is concerned.
Recently however (over the past 4-6 weeks) he seems to have pretty consistent issues with certain kinds of foods. The only common denominator so far we can think of is milk.
He used to drink milk a lot and eat a lot of cheese (and very much enjoyed these things). We were OK with this because it was a decent source of fat and protein, and since he doesn't eat meat...
Now however it seems whenever he has something heavy with milk (sauces, ice cream, milk itself, macaroni and cheese), he seems to constantly upchuck soon after. There are no lasting fevers, so pretty much after throwing up he's fine and running around, but we suspect he may be lactose intolerant so have made appointments with the GI to get tested and have started keeping a food journal.
Considering that - his small stature/lean weight to begin with, mostly vegetarian diet, and now possible aversion to milk and most cheeses, we're wondering some of the best ways to get him the necessary fats and proteins without having to constantly feed him (i.e., making it seem like a chore to him).
We're considering coconut milks, oils, soy/tofu (as of yet he hasn't shown an aversion to that...), and various fortified foods, but just wondering if anyone else has had experience with this or had any suggestions.