Speculation on the Why of Fat vs Protein vs Carbs

(Failed) #1

This is totally my mind wandering wherever it will this morning, but because I like to be able to see the logic behind things, I got to thinking about what logic there was behind fat not increasing your hunger hormone, insulin, and carbohydrates drastically increasing it, versus protein only mildly increasing it.

So, here’s my totally off-the-wall, probably idiotic, theory.

If ancient man was primarily a hunter/gatherer, the condition of the animals being hunted and consumed could possibly trigger the body to prepare for hard times or good times.

For instance, if the animals being harvested were fat and sassy, you would be consuming more fat and letting the body know that there was lots more where that came from because obviously they were thriving.

On the other hand, however, if there was a drought condition or other environmental problems for the prey, they would be leaner. The proportion of fat on them would be lower, so more protein would moderately signal the human’s body that there might be a problem coming up, and it might be a good idea to store some fat.

If prey was scarce, and humans had to survive on roots, seeds, plants, fruits, and berries, the body would say “Hey hard times, need to store fat NOW!”

I’ll go away now, LOL. :upside_down_face:

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

I think it’s even simpler than that. In sufficient concentration glucose is toxic. Ask anyone with diabetes. So a mechanism evolved to scavenge glucose from blood to prevent it getting to toxic levels. The only way to store that energy for future use is in the form of fat. Thus, the action of insulin to remove glucose from blood, store it as fat and prevent existing fat leaking out of storage. The carb component of foods is most easily converted to glucose, so insulin gets stimulated quickly into strong reaction to the flood of glucose entering the blood from the gut. Some amino acids resemble glucose and are easily converted to glucose via gluconeogenesis, so I suspect the presence of those amino acids in the blood stimulates insulin ‘just in case that stuff suddenly turns into glucose and I have to do something with it’. Fatty acids and ketones do not convert to glucose easily, so insulin just ignores them. Not a scientific explanation, of course, but I think useful.

(Failed) #3

I understand what you’re saying, that is the process that works in the body. What I was speculating on is how it evolved to be that way.

(Michael - When reality fails to meet expectations, the problem is not reality.) #4

I suspect we’ll never know the full answer. Glucose in sufficient concentration is toxic for our primate ancestors who eat/ate carbs pretty much exclusively. They get diabetes:


So what I said seems to apply to how the mechanism to control glucose concentration evolved. As human primates evolved to fuel a growing brain our gut’s ability to digest/process bulk food (ie high cellulose carbs) diminished. This because we needed to redirect much of the energy required by the gut to the brain, and to get sufficient energy had to adapt to getting it in the more concentrated form of fat and protein. Hence we became more dependent on insulin doing its job effectively.

(Full Metal KETO AF) #5

Most of the primates are herbivores. The more evolved apes like chimpanzees are omnivores. They are also the most intelligent primates next to humans. I think being able to switch between plant and animal foods is just a trait of more evolved primates. :cowboy_hat_face:

(Bacon is a many-splendoured thing) #6

The first two posts are clearly both part of the story.

Since we no longer have the guts to cope with mostly plant-based diets, I’d say that while it’s a good thing we never lost our ability to handle glucose, we clearly need a lot more meat and fat than the dietary guidelines want us to have. On the other hand, the small quantity of fruit our ancestors would have gotten would, in most of their ranges, have signaled the change of seasons, and the fact that increased insulin blocks our leptin satiety signal would have promoted fat storage in preparation for winter. Not that they ever hibernated, but a little extra fat reserve surely must have come in handy.

Something to bear in mind, as well, is that the herbivores with the kind of gut that allows them to process large quantities of plant material are living off the fat produced by their gut biome, not directly off the glucose from the carbohydrate. So fatty-acid metabolism must have been a large part of our digestive system, even before we became carnivores and lost the gut.