How well you eat, how well your kid eats might be the most critical thing?

100% percent red meat diet, beef and lamb. Ideally grass fed.

The hierarchy: on top is organ meats like beef heart, beef liver, beef kidney, beef intestine, tripe. Beef tongue at all you can eat Korean barbecue is the best.

After that, some sort of grass fed flesh meat, 100% grass fed ground beef, or grass fed Lamb.

Also let us never forget bone marrow… The food of the demigods and Achilles.