In Korea they have something called 미숫가루 (roughly: “Mee-soot-gah-roo”) which is very old and traditional food made of roasted and ground grains and sometimes legumes as well (sometimes over 20 different kinds)…just mix with water or milk and drink. I haven’t seen a nutritional breakdown of it, but when you start to consider things like buckwheat, sorghum, and so forth mixed with types of peas and beans, it’s gotta be pretty nutrient rich and have a lot of protein too. This is the original soylent, and it tastes good, but people often add a bit of honey or brown sugar.
On an only slightly related note, I’ve never had real koumiss, which is made from fermented mare’s milk and horse blood, but I’ve sampled a similar recipe made from cow’s milk/blood and it was quite a lot better than I expected. I can’t say I’d go looking for it in the shops, though.
Just ask anyone who works there, they should be happy to point them out. Lambics frequently have fruit added to them (like yogurt or shandy), but there should probably be a plain one, too. I’m not really into lambic so I can’t give any personal recommendations, but I imagine trying a random lambic can only go so badly.
