Maybe Korea's issue (as well as other East Asian countries) issue with a rice-based diet (especially white rice) in the absence of modern levels of consumption of meat or other animal-derived food. While bread (especially whole bread) has some level of protein in and of itself, and Italians have also had cheese and milk available at least some of the time, trying to survive off of a diet of rice and vegetables must be particularly unsuited to growing to your genetic potential. My impression of Korean food is that it would be quite unsatisfying from a nutritional standpoint without the meat, whereas Indian and even Chinese food seem to be a little more nutritious.