You aren't going to find dramatic changes in 1980. The human body is remarkably adaptable and many health problems accumulate over years or possibly even generations (epigenetics). Obesity implies an impaired metabolism, which takes years (used to be decades) to develop. Moreover, health problems have been epidemic in our society pre 1980 (just with less dramatic consequences). I think you are going to really limit yourself with a 1980 cutoff, and that it is more likely that the same factors just got worse around that time.

This doesn't ring true. Epigenetics may take a lot of time, but memetics don't. Social changes can produce sharp changes in diet very quickly. Many epidemics predate 1980, but obesity, by the numbers, does not appear to.

Yes, social changes could produce dramatic changes. But social changes themselves are usually very slow, and I know of few exceptions to this in the context of health. Normally people blame obesity on social aspects (like exercise) which 1) have changed very gradually and 2) don't matter anyways (explaining that would make this a much longer discussion). If someone could come up with an example of just 1 social change that dramatically shifted in 1980 I would be very open to the idea. The only thing I know of is weight-training- the obesity numbers used are normally just based on BMI- they don't take into account that muscle isn't fat.

Here are some actual numbers: http://en.wikipedia.org/wiki/File:USObesityRate1960-2004.gif What we see is a linear increase starting around 1980, where before then rates appeared to be constant.

Before 1980, 1/3 of Americans were overweight. Every overweight person has the same metabolic problem as the obese, just to a lesser extent. The fact that 1/3 of Americans are now obese 20 years later is what I would expect due to a gradual decline of American health that hit a tipping point for obesity around 1980.

Not just fructose. In fruit fructose is fine. High fructose corn syrup is different and became prevelent in the 80's because of the sugar tariffs in the late 1970's in the USA.

Fruit fructose is just as bad as the fructose found in HFCS.

Bad/good. Forget those descriptors.

Fructose found in fruit is indeed no different. But it is in fruit, bound up with fibre, protein, and many enzymes. In HFCS it's just fructose.

The delivery mechanism is more important here than the lab breakdown.

not really, fructose no matter the form is ot broken down in the gut so its shunted to the liver (much like other toxins). There it does all sorts of crazy stuff.

Modern fruit (due to selective breeding) is ultra sweet with what I can assume were pretty bland flavored fruit back in the day. Natures Candy.

Fruit has always been selectively bred. It's a bribe to animals.

My experience is that supermarket varieties of fruits are bigger and look better than local, traditional produce, or are more practical in other ways (thinner skin, less or no seeds) but are often insipid in comparison.

On the other hand (and this is just speculation), in the northern hemisphere most fruit is naturally available in the fall season. Fattening prior to winter was probably a desirable effect.

Yes really, the delivery mechanism can change how fast it hits your system, and that makes all the difference. Your liver can handle X amount an hour but not Y amount an hour before shit starts acting up.

Yes, it's a matter of quantity, not quality. An Apple contains something like 7 grams of fructose. One can of soda contains 25 grams of fructose. According to the National Soft Drink Association, average consumption in the U.S. is nearly two cans of soda per day. (One can per day is enough to add 16 pounds of fat per year)

That's roughly equivalent to 7 apples, every day of the year. That's way, way above our actual fruit consumption levels.

Apples also have fiber attached to their fructose.

I was not disagreeing that fiber is important, only pointing out that even when eliminating any other considerations the difference in quantity is enough to account for the trend.