I gotta say that any article about why it was easier to be skinny in the 80's that doesn't mention crash diets, cigarettes, and cocaine is just a little hard to trust.

You're right, but it's still good to see the microbiome make an appearance:

A study published recently in the journal Obesity Research and Clinical Practice found that it’s harder for adults today to maintain the same weight as those 20 to 30 years ago did, even at the same levels of food intake and exercise.

...

First, people are exposed to more chemicals that might be weight-gain inducing. Pesticides, flame retardants, and the substances in food packaging might all be altering our hormonal processes and tweaking the way our bodies put on and maintain weight.

Second, the use of prescription drugs has risen dramatically since the ‘70s and ‘80s. Prozac, the first blockbuster SSRI, came out in 1988. Antidepressants are now one of the most commonly prescribed drugs in the U.S., and many of them have been linked to weight gain.

Finally, Kuk and the other study authors think that the microbiomes of Americans might have somehow changed between the 1980s and now. It’s well known that some types of gut bacteria make a person more prone to weight gain and obesity. Americans are eating more meat than they were a few decades ago, and many animal products are treated with hormones and antibiotics in order to promote growth. All that meat might be changing gut bacteria in ways that are subtle, at first, but add up over time. Kuk believes the proliferation of artificial sweeteners could also be playing a role.

Read the study: http://www.sciencedirect.com/science/article/pii/S1871403X15001210

Birth of the Internet == sedentary lifestyle?

Birth of Cable TV, Internet, and Cellphones. Yesh.

Cocaine was very helpful... but what about all those Meth labs today?  We should have an epidemic of skinny, edgy folks throughout our midwest at least...