There is plenty of science (but not 100% proof) that indicates his diet is Paleo in nature. From AI.

His favorite snacks are nuts and blueberries.
His main diet consists of fish, chicken, egg whites, and vegetables, with protein powder as a complement.
He avoids oil, butter, and sauce when dining out, opting for steamed white fish and vegetables.

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He's on a protein based diet. He could probably be even younger if he adds in red meat (grass fed/finished) instead of protein powder! And there is nothing wrong with butter and egg yolks. Your brain is made of fat and cholesterol! Bet your doctor/Government did not tell you that before they tried to get you on a low fat diet and take statins to get your cholesterol down!