I was on the Chuo line in Tokyo this morning when a family of 4 Aussies got on with their huge suitcases, headed to Tokyo station and presumably on to the airport. Two middle-aged parents and two tall, strapping 20-something sons.
Mom asks red-headed dude, “What did you eat for breakfast?”
“Bacon, sausages and eggs,” he replies.
She just raises her eyebrows.
I wanted to jump in with “Hey! Zero carb, eh? kcko!” but held my tongue…
Signs of progress among the young.
No. Just a delicious breakfast.
Most kids at 20 are slim - at least outside of the U.S.
I think you’re getting over-enthusiastic to think that he knows anything about keto or is just “turning on” to the idea due to some critical mass in a collective consciences shift in humanity. 
On the other hand, if you had mentioned something about keto, you would have allowed them to learn the virtues of a keto diet and perhaps lead to a new awaking for them.
Next time, speak up.
Maybe they are too young, maybe not… It reminds me of a lunch out with the girls that I had recently and I ordered my usual mushroom swiss burger minus the bun with a side of sauteed mushrooms…I told our hipster waiter that it was my keto lunch and he smiled and slowly bobbed his head and said “Niiiiiiiiice”. So who knows! 
I see way more people eating low carb and it shows when service folks dont even blink when you say “no bun and no fries” please.