IIRC rice isn't very nutritious, it's just calorie dense. In that regard adding hemp seeds to your diet may do more in the long run.
https://doctor.ndtv.com/living-healthy/8-myths-about-rice-yo...
Kid might go for Sugary drink or cereals or snack over something like broccoli
What does it prove?
People in south Asia atleast don't consume Rice alone, rice has handful of amino acids when it's coupled with lentils (of different kinds) which have other complementary amino acid profile it becomes a complete protein like any other protein from whey
This is often smth which Indian people say, "bro our diet lacks protein". Yea what you consume everyday as "Dal bhaat rotti" if if it's protein then what it is?
More something like it's healthy and they know it. By whatever means...