This is an interesting article of how Yuzuru had gained stamina by food conditioning. It is long and has lots of technical terms, so I will just try summarizing some parts.
http://wedge.ismedia.jp/articles/-/13516
After Sochi Olympics, Yuzuru continued to do food conditioning and he gained more muscle, his buttocks became bigger and he felt tight in that part of the costumes. Before PC Olympics, he had light meal at night but sufficient meal in the morning and noon in his daily life in order to adjust to the time schedule of his skating order. He had early breakfast, and lunch at the timing of not getting hungry before the time of the competitions, calculating the calories and had jelly and so on because they didn't stay in the stomach. He spent some period of time to do this before the PC Olympics since his body had to remember its rhythm. He and the team (Ajinomoto)'s motto was "Lively muscle and get the gold with muscle glycogen", and basically he had well balanced three meals and took "Amino Vital" around the time of practice and competitions. When he got nervous just before the game, he couldn't eat well and have enough protein, but Amino Vital helped in giving him nutrition he needed (he also had small rice ball called "power ball", a ball was only 50g and was easy to take when he got tense before the game.) After being injured at NHK, he tried to have lots of protein, especially the type of BCAA (don't know what it is lol) while he was strengthening body core off the ice. Mr. Kurihara from Ajinomoto had kept in touch with him and gave him advise "To recover from injury, the important thing is to have much protein." His dietary habit had apparently been changed since Sochi Olympics, he came to eat sufficiently and clean up his plate mostly. He sometimes gained 3000 kcal to 3500 kcal a day which was far surpassed the calories a normal male took.
We can see the photos of the meal in page 3 and 4