To Which I Would Add

An interesting finding on public health prompts unimpressively incomplete speculation:

Why It Was Easier to Be Skinny in the 1980s

A new study finds that people today who eat and exercise the same amount as people 20 years ago are still fatter.

A study published recently in the journal Obesity Research & 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.

The authors examined the dietary data of 36,400 Americans between 1971 and 2008 and the physical activity data of 14,419 people between 1988 and 2006. They grouped the data sets together by the amount of food and activity, age, and BMI.

They found a very surprising correlation: A given person, in 2006, eating the same amount of calories, taking in the same quantities of macronutrients like protein and fat, and exercising the same amount as a person of the same age did in 1988 would have a BMI that was about 2.3 points higher. In other words, people today are about 10 percent heavier than people were in the 1980s, even if they follow the exact same diet and exercise plans.

Ok, that's surprising. As a casual follower of this type of research I am aware that a lot of these physical activity and daily diet datasets are based on not wholly reliable surveys. But the authors of this study are surely aware of that, so let's press on to the speculation:

“Our study results suggest that if you are 25, you’d have to eat even less and exercise more than those older, to prevent gaining weight,” Jennifer Kuk, a professor of kinesiology and health science at Toronto’s York University, said in a statement. “However, it also indicates there may be other specific changes contributing to the rise in obesity beyond just diet and exercise.”

Just what those other changes might be, though, are still a matter of hypothesis. In an interview, Kuk proffered three different factors that might be making harder for adults today to stay thin.

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.

Well fine, but let's take a suggestion from Captain Obvious - cigarette smoking is way down, which is surely a good thing, but it is also likely to have contributed to weight gain.

Per Wikipedia, linking CDC statistics:

Smoking rates in the United States have dropped by half from 1965 to 2006 falling from 42% to 20.8% of adults.^[39] As of 2013, the number of American smokers is 17.8% according to the Centers for Disease Control and Prevention.

So we have half as many smokers as formerly. And from ABC News, July 11 2012:

Weight Gain After Quitting Smoking: Average Over 10 Pounds

As more people quit smoking cigarettes to protect their health, many face a new battle: weight gain. A new study in the journal BMJ shows that quitters gain more weight than anyone previously thought.

The research found that those who quit smoking gained an average of 10 to 11 pounds after 12 months, with most of the weight gain in the first three months.

Still, that shouldn't stop people from kicking the habit for good, the researchers said.

Scientists from France and the U.K. conducted a meta-analysis that examined 62 European-based studies of weight gain among people who had successfully stopped smoking. They said the average weight gain was higher than doctors generally thought, though there were substantial differences among study participants.

By way of comparison, the "dramatic" increase in anti-depressants since the 70's was described by the National Center for Health Statistics and summarized at a Harvard Health blog in 2011:

According to a report released yesterday by the National Center for Health Statistics (NCHS), the rate of antidepressant use in this country among teens and adults (people ages 12 and older) increased by almost 400% between 1988–1994 and 2005–2008.

The federal government’s health statisticians figure that about one in every 10 Americans takes an antidepressant. And by their reckoning, antidepressants were the third most common prescription medication taken by Americans in 2005–2008, the latest period during which the National Health and Nutrition Examination Survey (NHANES) collected data on prescription drug use.

So from 2.5% to 10%. of the population from a late 80s starting point. And the weight gain, per the article linked by The Atlantic? Uhh, ambiguous on net, although dramatic for some:

Antidepressants are the most-prescribed drugs in the U.S. for people between the ages of 18 and 44, and more than 10 percent of Americans are on them at any given time. And yet, some people who desperately need to be taking them are afraid to start because certain types of antidepressants have been associated with weight gain.

And some don't.

Two recent studies add more (contradictory, sorry) threads to the depression-weight tangle.

First, a JAMA Psychiatry analysis of more than 19,000 patient medical records found that people taking antidepressants did, in fact, put on a few pounds, but only a small amount. At most, it was only about two and a half pounds, in the case of the SSRI citalopram (which is marketed as Celexa). And people taking bupropion (Wellbutrin), which is not an SSRI, actually lost a half a pound.

Well that doesn't panic me.

However, another study published in the journal PLOS One found that antidepressants come with a strong association with obesity. Among women with a history of depression, those who took antidepressants were 14 percent more likely to be overweight and 71 percent more likely to be obese than women who weren’t on antidepressants.

So anti-depressant use is associated with obesity? Are we going to attempt to relate cause and effect here? No:

One reason this riddle is so hard to solve is that the depression makes some people lose weight, and others gain it. Thus, taking an antidepressant that just doesn’t happen to work very well might lead to weight gain—not because of the drug, but because the depression hasn’t gone away. Importantly, the PLOS Study didn’t measure whether the patients were obese to begin with, and the JAMA study didn’t prove that the antidepressants were responsible for the weight gain.

Well. When in doubt, do some fuzzy math. Per the lead, the population is ten percent heavier today for the same exercise and diet. Let's call that fifteen pounds on a one hundred fifty pounder from 1980.

On the cigarette side, if 20% of the population gained ten pounds, that would average two pounds per person across the full population. That leaves most of the fifteen pound weight gain unexplained.

But on the antidepressant side, if 10% of the population gains, hypothetically, 20 pounds, the average gain per person is still only equal to the cigarette result and the antidepressant studies cited ought to have come up with more decisive results.

So for my money, the cigarette weight gain, whatever it actually may be, probably is more important than the antidepressant effect, even though neither seems to explain much of the fifteen pound apparent puzzle.

One more thought - ritalin and the other ADHD medicines handed out like popcorn to adolescent boys often jam up a growing boys appetite and weight regulation. I have certainly seen young men with a post-ritalin weight management problem. And apparently my anecdotal experience has real science behind it:

Childhood ADHD Linked to Obesity in Adulthood

Increased risk of adult obesity is one of the long-term consequences facing children with ADHD, even if their diagnostic symptoms fade

 

And the drugs used to treat ADHD seem to be part of the explanation:

 

ADHD medications may cause teenage weight gain

 

Stimulants like Adderall or Ritalin could be a risk factor for childhood and adult obesity rather than childhood ADHD.

 

Now, the timing may not work - if we had a surge in ritalin use during the 90's, a medicated ten year old from 1995 would only have been 23 in 2008, the cut-off for the weight survey study data. And can gender differences in ritalin prescriptions be related to gender differences in the weight gain study? One more place to look.

 

Comments

[GMax]

Primero

[GMax]

OH YEAH!

[henry]

Was it the Ritalin or smoking cessation?

[Porchlight]

Are they factoring in the increased proportion of desk jobs? Of adults with no job at all? Thirty years ago, more people were in jobs requiring physical labor.

[Rick Ballard]

Median age in 1990 in the US was 32.9,in 2010 it was 37.2 years. Check the movement of the bulge in the population pyramid before considering considering other factors affecting bulges.

[peter]

what does it mean to be first in a thread with only six posts? It's like Division 7 wiffle ball

[Ignatz Ratzkiwatzki]

When did all this primero envy start?

[daddy]

If the report is true I think it may have to do with how much time we spend on the Internet, which 99 times out of a hundred involves plopping down and sitting somewhere, and only as Porchlight's hubby says, for JustOneMinute Just 10 Hours.

I know I spend a ton more time on the internet now than I did 10 years ago, and I doubt any of us do the walk outside in the morning to pick up the morning paper anymore.

[glasater]

Thanks for the research on this topic, TM and one I'm pretty interested in.

Wonder how the use of steroids being prescribed frequently has a factor in the weight gain department?

[Dave (in MA)]

Yeah, real conservative.
h/t Stephanie

[buccaneer morgan]

warn us, dave next time,

[Belle]

The bitch. And I am not talking about Behar.

[Ignatz Ratzkiwatzki]

If he'd gone through with it I could respect him...a little...but then he'd cry and ruin it.