I ran the 2004 Chicago marathon. My training was less than recommended and I had only worked up to a long run of 15 miles, so the last 11 miles were a challenge. But I finished, and in the top half, so I was happy.
In 2005 I went back to watch the race and cheer on my cousin. Watching the race unfold helped me formulate a theory why the Kenyans dominate all the big marathons.
October 9, 2005. Chicago marathon, 13.1 mile mark, halfway.
We stood in the 2nd level of a parking ramp across the street from the Sears tower. We waited to see the lead runners.
As the mob of people along the race course thickened, anticipation grew. It was an early morning-party atmosphere. My kind of party.
Suddenly, a cheer! Whistles, bells, shouts, “Here they come!”
“They” came rolling by. The lead wheelchair racers finish in about an hour and a half. They also get a head start. So we waited some more and cheered on the slower wheelchair racers.
The lead pack of runners went by so quickly, I barely had time to study them. There were ten in the pack. They looked very comfortable running together, even at a speed of over twelve miles per hour.
I thought I saw two-time defending champion Evans Rutto in the middle of the pack. I assumed the pack was all Kenyans. I was right.
Fifty yards behind the lead pack a solitary runner struggled. A few more yards back, another runner, then another, then two, then three. They all seemed to be struggling to maintain the pace they had run in the first half of the race. None of them looked like they could mount a challenge to the Kenyans. I was right.
The runners behind the Kenyans seemed to be so alone. Even if a few runners were grouped together, I could tell they were running alone.
In contrast, the Kenyans seemed to be running as one unit with interchangeable parts. And in a sense they were. And I think the Kenyans, with great humility, realize that.
The Kenyans finished 1st through 10th, with only 5 minutes between them. Evans Rutto, the two-time defending champion, finished 4th, 26 seconds behind his countryman, Felix Limo.
How humble is Rutto to win Chicago twice, and then finish a few seconds behind his fellow countryman? Is it coincidence the Kenyans train and race as a group and dominate the way they do?
Curiousfarmer 
I thought you might have a thought or two on the nutritional aspects of why the Kenyans run sooo much better than most.
I’m training for a half marathon w/ a neighbor and running 6 miles on sunday…long run day. And, my old thinking says “oh, my what about energy? what about glucose? what about….” ad nauseum.
It’s not like I run a 7 minute mile. sheesh.
Now I’m a little more excited. Still would enjoy your musings about the nutrition aspects and ‘do I eat that banana half way or energy bar?’