I'm nowhere near as 'trained' as Steve and for my most recent long ride, on Sunday (Suffolk to Herts) over Steve-esque terrain, I stopped to eat at Saffron Walden after 4hr 43 minutes (103km).
Seven hours before a food stop isn't that amazing- I often go more than seven hours between meals, and Steve is working at a pretty low heart rate.
There's an awful lot of research showing that there's absolutely no need for constant feeding of carbs while riding-especially if you're not at high intensity.
I don't wonder where the vitamins and minerals are coming from. He's drinking protein shakes which are fortified, and he's eating real food.
A 'typical' high fat diet is full of processed foods. My diet's full fat (60% of calories from fat) but it doesn't feature doughnuts- that fat is from meat & dairy & nuts where it's bundled with minerals and proteins, and it's accompanied by plenty of vegetables.
Steve's not stupid, and he's got advice. I think he's doing alright.