I remember reading somewhere that when agricultural grains were introduced into our diets, humans went from an average of 6 feet tall to 5 feet. Also, cultures that have the longest history of grain consumption (Asians) tend to be the most shortest out of all the races. Finally, the Japanese went from an average height of 5'3'' to 5'7'' when they started eating less grains and more meat post ww2 when they were introduced to eating more eggs, meat, and dairy. Are these all just weird coincidences, or something else?
I would guess that it's not so much what they're eating as what they're not eating. When your daily food intake consists of little more than brown rice and a very limited selection of vegetables you're bound to be missing certain nutrients in your diet. Edit: And a nutrient deficient diet fed to a child results in stunted growth, among other things. Kwashiorkor (a condition resulting from a diet that contains an adequate amount of calories but not enough protein) in children can damage them in myriad ways, even including lowering their IQ permanently.
I have read a reference to that as well. I'm not sure if the rational was insulin levels. I kind of doubt the theory in general but I would love to read to article in full if anyone can find it.
lack of protein = nutrient deficiency in AA, less growth hormone excreted. thats what probably stunts growth. remember just like the egg article... correlation doesn't = causation. insulins sole purpose is to get rid of blood glucose when it gets too high. Asia doesn't have high insulin problems from rice (for the most part in its history). their diet is mainly low sugar, and the worst thing about it is white rice. i really doubt it has anything to do with stunting growth. geez you people act like every carbohydrate causes an insulin spike. asians typically eat white rice, vegetables, and fish. unless they are eating obscene amounts of white rice (they usually eat a small bowl the size of a cup), i really doubt they are spiking their insulin. also, while diabetes is increasing world wide (including asia), asia still has the lowest rates in the world, which concludes that they dont have as much insulin resistance as other parts of the world, which means... most likely they have less insulin running in their systems compared to the rest of the world. so my opinion, no, its not insulin that is making people short. most likely its genetics, the reason they are growing, is that something in their enviroment is affecting their gene expression (GXE, variable expressivity).
Well, Asians have been eating grains longer than the other races, and therefore most adapted to grains.
I'm sure diet has a role in almost every aspect of a person's health and physicality, but you can't ignore genetics. Breeding two huge dogs will most likely result in a litter of large dogs, breeding a large dog with a small dog and continuing to breed that line of dogs with smaller dogs will most likely result in smaller and smaller dogs.
Yeah, if diet did play are role in height, I doubt it would be at the adult or near adult level. Theirs vegan/vegetarian athletes at top levels of many sports. However, none of them seemed to follow that sort of diet when they were kids. True, but what I don't get is why would people evolve to be shorter?
one hypothesis: food shortage back in the days = people with higher caloric requirements died out (meaning tall and big) short people survived, procreated. natural selection at its finest. thats one hypothesis. im sure more people can come up with better ones. but it probably boiled down to the fact that being short was a survival advantage in that environment and time, while being big was not.
