Interesting.
I think the bombardment sometimes weekly, of super heat on the nervous system of the developing fetus by ultrasonography is worth considering.
Diet is very very causative in heart disease, and obesity, both which are new, but since the early 20th century.
Whit sugar, flour and pasteurized dairy are problematic, as are products processed from non grass fed meat.
But Autism - I don’t know. Maybe.
Exercise is more important than diet when it comes to obesity. Heart disease is more genetic, but is also enhanced by a sedentary life style.
Both were well known in the past. R.E. Lee had heart problems and high blood pressure. Look at drawings from the 18th and 19th century, obesity was quite common among the landed classes. The general rise in prosperity in the West has enabled even the poor to live that lifestyle now.
My grandfather lived to be 98 years old. He spent 46 years in the U.S. Army and was retired 36 years (he had a one year break in service in 1917). He had bacon and eggs fried in the bacon grease for breakfast 6 days a week and pancakes/waffles and sausage on Sundays. He also walked 4 miles in less than an hour every day but Sunday.
I have lost count of the farmers I have encountered who are in their 70’s and can out work your average 18 year old. The farmers eat well too. It is when someone convinces them to give up working and retire that they die. Typically in about four years. This is why I took up golf, when I am forced to retire by the SS I can walk 18 when I am not at my part time cash job.
Sweeteners in everything is part of the problem too. Sugar, corn syrup, or fructose so it “taste good”. I make a lot of stuff from scratch. With meats it is the hormones and antibiotics, not the grain feeds. I do think grass fed taste better, but grain fed is more tender. Find a butcher who does local critters.
How does all this relate to autism? My contention is that the rise in autism (and most of the other modern health issues) is related to the rise in health fads in the 70’s. Specifically, that not drinking at all during pregnancy may be linked. Also, no one has explored the previous recreational drug use angle either.