As ridiculous as it sounds, that's what it boils down to for millions upon millions stuck in the sugar crack-house.
"Hypoglycemia" has to be the most overused, misunderstood condition in existence, perhaps with the exception of "I got the flu" (most of what people identify as "flu" is simple food poisoning).
I had an interesting experience over the weekend, when I took part in a fairly rigorous hike, about 4.6 miles round trip, but with three miles of that on an average 15% grade. To make it more interesting, we were camped up top, so it was first about 3/4 mile on pretty flat terrain, then the descent for 1.5 miles. It was steady, as though along a canyon wall, not a switchback trail.
I took along about 3/4 of a pint bottle of water, no food. Others had their hydration packs and other supplies. Three of us reached the bottom 10 minutes ahead of the group of four behind us. I wasn't thirsty, so I didn't take on water. Once the other four arrived, out came the Cliff Bars, nuts, fruit, and other things. I was offered, but politely declined. What those hikers did, but probably didn't realize they did, was to foreclose on their body's ability to get any fat burn going for the rest of the hike. Even if you're skinny, it's still a good idea to keep your body familiar with the process.
We all left at the same time, and it was immediate ascent. I started out on a slow, even pace, gradually increasing it. As I began to break a good sweat, I removed my shirt. Instead of wiping sweat (coolant) away, I spread it with my bare hands over my face, torso, and arms. I did this two or three times with surprising results in terms of a bit of an energy boost. Being able to cool is a huge advantage. At no time was I even slightly hungry, or even thirsty until the very end when I took in about 8 ounces. Nor did I need to stop for rest. The climb was grueling in the sense that the grade was so steady, with nary a flattening.
I outpaced one hiker by 20 minutes, and the rest of them by 30. The rest of them were among those who had to have their mid-hike "energy," and I heard that along the climb, one got "hypoglycemic" and had to chew on an orange. I kept my mouth shut, but it's more likely that this hiker simply never wanders out of sugar-burning mode, and since she never does, her body knows just how to scream bloody murder when she even gets close.
I think it's very appropriate to challenge yourself on short hikes like that. I once tried to do Half Dome in Yosemite while in ketosis some years back. That's about 12 miles or so, round trip, ascending from about 4,000 to 9,000 feet and back. Very tough, and I got leg cramping and had to turn back about 3/4 in. A year later I made it handily on white-bread bologna & mayo sandwiches and water.
Oh, yea, and I did it all in my Vibrams, of course (this hike; they weren't invented when I did Half Dome).