Sardines, hmm. Given his science leanings, he might be trying to go sort of holistic moderate lowcarb (South Beach-esque, perhaps, maybe not so strict on fats) trying to get as much nutrient density from food (vs. vitamin supplements) as possible. I just say that because "sardines" is sort of code for getting calcium and Omega 3.
http://www.nutritiondata.com/facts/...products/4114/2

And it keeps "seafood sustainability" in mind.