My opinion - food processing and the agricultural revolution. A metabolic derangement caused by overly processed agricultural products.
> "Humans up until a hundred years ago (or so) had a need to do it."
Actually, the aristocracy and nobility have all suffered from obesity since ancient times. Historical texts have many, many records of... robustly sized... monarchs, nobles, and the rich. Indeed, the image of the rich fat-cat is a lot older than merely the last century.
> "My opinion - food processing and the agricultural revolution. A metabolic derangement caused by overly processed agricultural products."
Or perhaps more simply, the majority of the population stopped doing hard physical labor day in day out. We started sitting behind desks for 8 hours a day instead of toiling in a field or factory for 12.
I'm also willing to believe that we are simply eating more than we used to. In industrialized nations the ratio of food cost to income is almost laughably low - compared to agrarian nations where the cost of food can sometimes be up to half of a family's income. If you look at countries with smaller average serving sizes you will see a corresponding drop in obesity rates.
Thankfully I think the country is starting to come around to the notion that no amount of sodium reduction, fat-reduction, or carb-reduction will work if you continue to shovel it into your mouth by the gobful.
It's become vogue to blame every ill of society on industrialization, when instead the answer seems to be simpler and more obvious.
Edit: I suppose people don't see the connection between over consumption, availability, palatability, and processing.
I think potatolicious makes an excellent point- "processing" (the popular demon today) cannot be pointed to as the sole cause. It is probably part of the problem, but probably not the root.
Fruit tastes good, and rich people could get as much as they want, but they generally don't get fat on fruit. Confectionery items on the other hand...
What I'm saying is that over-consumption and processing drive each other.
Well, I suppose confectioneries in particular with confectioner's sugar could be considered "refined"...
Removing of fiber, adding of sugar, etc.
The end result of many types of processing is a food which is both more nutrient dense and less filling.
The things I usually want to shovel in my mouth are carbohydrates, and insulin spikes explain at least part of that. I eat far less when I'm trying to keep my insulin low.
Everyone knows you have to eat less to lose weight. The question is how. Some techniques are more successful than others.
We are learning that certain things in the diet (sugar, grains) promote metabolic issues that fuel overconsumption.
The ideal state of being, which everybody would like to enjoy, is being able to eat until you are full and then stop.
That is not such a simple process from a hormonal standpoint.
Limiting calories works. Keeping people doing that long enough to lose weight, and the rest of their lives to some degree (so no yo-you dieting) is the true challenge.
Have you never seen an obese dog or cat? Feeding to much of the wrong food will make any animal fat.
I guess my point was not clear enough.
Feeding any animal an improper diet can lead to a metabolic problem where satiety and fat deposition do not work as intended.
Animals in the wild eating their natural diet do not have a need to limit their consumption. They self regulate effectively.
They may exist in a world of scarce resources, especially predators, but they are not constantly living on the edge of starvation.
http://www.michigan.gov/dnr/0,4570,7-153-10370_12150_12220-2...
It's simpler than that: dense food and lack of exercise. More people have access to more calories than at any other time in history. At the same time, we spend more time at work and at play sitting and expending minimal energy than at any other time in history.
http://news.yale.edu/2012/08/02/hunter-gatherers-expend-same...
People researching modern hunter gatherer societies are finding that they expend roughly the same amount of calories as westerners.
Perhaps the fact of moving changes how the body partitions nutrients. Or handles hunger. Or some other factor. Or the specific modalities of exercise (brief, high-intensity vs. long, low-intensity) matter.
The study appears to rule out one possible mechanism (total calories consumed). There's still the fact of bodyweight / body composition differences.
If your test fails to account for observed differences in phenomena, then your test failed to identify the cause(s).
Just as the sick man who goes to the doctor for a battery of diagnostics and is told "we can't find anything wrong". The problem isn't in the state of the man's health, it's in the state of the doctor's diagnostics.
I don't have a particular reference, just piecing together the non-trash results of googling 'diet height' and 'history of human height'.