Though I am almost a vegetarian (though not strict, since I do occasionally eat fish, and eggs- and raw goat's milk dairy) the parents were not correct in only permitting rice cakes, wheat grass and almond milk.
While all three are very nutritious foods in thier own right, they are not the ONLY foods those kids should have had access too. The kids should have been permitted berries and all organic fruits, raw milk and organic veggies rich in magnesium. They also should have been given all the foods with essential oils contained like raw nuts and sunflower seeds. Salads with every kind of veggie and sunflower seeds, with a good apple cider dressing and olive oil should have been available daily for them.
They should have been permitted
Watermelon with the seeds-- especially to keep hydrated, as well as coconut juices during warm weather.
Wheatgrass is good, but not enough, or else God would have only created wheatgrass for everyone to eat with nothing else growing around. Kids- and probably all of us, should have a meal with very colorful foods containing all the nutrients, Beta Carotene, Lycopene, etc.
If they didnt want to give the kids protein from fish or eggs, then at least Hemp grains would have been a good choice-- Hemp grain is very rich in protein. Kale, Broccoli and Collard greens are also rich in Calcium.
Get the daily allotment of healthy sunshine on the body, and they would have been able to assimilate the calcium from the greens.
If it were me, I'd also have the kids take some fish oil capsules in the Winter months- and make sure they got some kelp in thier soups and salads.
Kelp has anti-parasitic properties, as well as rich in potassium ,
Iodine and other minerals.