One of the best adverts for porridge that I can think of is chess player Victor Korchnoi. He survived the siege of Leningrad but, understandably, was pretty thin at the end of it. He resolved to eat porridge every day thereafter to build himself up. He was one of the best players not to win the World Championship, losing in three finals, but he won the USSR and European Championships quite a few times. Now, aged 77, he is the oldest active GM and is playing only slightly below his peak FIDE rating of 1979.