The Unusual Suspects

Researchers are uncovering some pretty strange culprits behind the obesity epidemic—everything from air-conditioning to infectious love handles

By Jill Waldbieser Posted 02.20.2009 at 1:51 pm 14 Comments

Fat Gulliver Tyson Mangelsdorf

Obesity is our century's version of the Kennedy assassination: Everybody's got a theory. But even with blame perpetually shifting -- one day it's fast-food corporations, the next it's genetics -- and a $40-billion-a-year diet industry, our waistlines just won't stop expanding.

The prevalent belief is that the problem is merely a matter of willpower. If we could only acquire some, the thinking goes, we'd be able to eat less, move more, and maintain a reasonable weight. It's a position backed by common sense, of course, but it's also the kind of oversimplification that could be the reason we're not coming up with any lasting solutions. "There's a sense about obesity that we already know all the answers," says David B. Allison, a biostatistician at the University of Alabama at Birmingham.

But in truth we're only just beginning to reveal them. Faced with a mounting collection of research implicating unconventional factors like viruses, pollutants and the amount of sleep we get, even the National Institutes of Health has begun to explore alternatives to traditionally held beliefs about weight gain. "We realize that obesity is more complex than we thought, so it's necessary to explore all possible theories," says Jerrold J. Heindel, the health science administrator for the National Institute of Environmental Health Sciences, a division of the NIH.

Weird as they may seem, the following hypotheses are quietly transforming the way we think about and treat obesity.

Artificial Sweeteners Make Us Fatter

THEORY
Sugar substitutes may blunt the brain's natural ability to measure calories, causing us to overeat.

EVIDENCE
On the surface, it makes sense that America's consumption of products made with no- or low-calorie sweeteners would increase at about the same rate as incidents of obesity -- after all, don't zero-calorie sweeteners go hand-in-hand with dieting? They do, but perhaps not in the way you might think. "Most people have assumed that as people gained weight, they increased consumption of artificial sweeteners," says neuroscientist Terry Davidson of Purdue University. "Our data suggests that [the cause and effect] could go the other way."

Davidson and his colleague, psychologist Susan Swithers, published their findings last February in the journal Behavioral Neuroscience. They fed rats either artificially sweetened yogurt or sugar-sweetened yogurt in addition to their normal rodent chow. The animals that ate artificially sweetened yogurt not only gained more weight, they also appeared to lose their natural ability to keep track of the extra calories and eat less later on.

"It's a Pavlovian approach to obesity," Davidson says. "Animals learn to use taste to predict caloric consequences, and in nature, sweetness is almost always an indicator of calories." When we experience a sweet taste with no accompanying caloric intake, it confuses that calibration tool. Repeating that experience, as in drinking a diet soda every afternoon, might actually deprogram your calorie-counting mechanism for good. (In the rats, effects were seen in as few as 10 days.)

FRINGE FACTOR
Moderate. Even skeptics admit that the evidence is compelling, but causality has yet to be proven in humans. And although rats have similar taste receptors as us, they have a more limited diet and don't respond to all sweeteners the same way as humans do. (The Purdue study focused on saccharine, one of five artificial sweeteners approved by the Food and Drug Administration and one that rats do register like us.)

NEXT STEPS
More study is needed.

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14 Comments

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Charles D. Dietzen

02/23/09 at 9:25 pm

Food. One must not forget about food, which is almost always implicated in cases of obesity.

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Eruantalon27

02/23/09 at 11:49 pm

Interesting take on some of the fringe cases that exist among the obese. I'm sure this can explain some frustrations when overweight people go on a diet and exercise while failing to see the fruit of their labor.
For 95% of overweight (read = inactive) people out there, it is hard to improve on: eat healthy*, get enough sleep, and exercise often.

* But avoid artificial sweeteners, processed food, white flour and most fast carbs, BHT, MSG, refined sugar, saturated fat, trans fat, artificial flavors, artificial colors, and stop microwaving your lunch in that darned plastic tupperware.

Society sure doesn't make it easy.

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AMP13

02/24/09 at 10:09 pm

It seems like these "researchers" are blaming everything except the one thing that actually counts.....food.
You just gotta know when to put down the fork.

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mikesicalieber

02/26/09 at 8:39 pm

These researchers are searching for all these hidden culprits that are causing the current obesity epidemic, when the answer is right in front of all of us. The real problem is self-control. People today have absolutely no self-control. We live in a society that promotes indulgence and immediate satisfaction. There is no secret here.

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royceee

02/27/09 at 6:22 pm

There is some truth as to the amount you eat HOWEVER a huge portion of of weight gain is WHAT you eat. If you can think back to the diet of say the 30's and 40's there was not the obesity and the food came from the garden and the farm without processing. I have problems with my weight and reverting back to basic diet as best I can helps a lot. There should be strict controls on modifications to the food chain in processing and tampering with the basic structure. There is a lot of quality reading and research on the net to back this up. Hope it helps.

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Popular_Scientist_AZ

02/27/09 at 10:05 pm

These are interesting theories and should be investigated but the other question is: can all of these causes of obesity be reversed by diet and exercise?

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oracle99

03/02/09 at 12:14 am

I find is a little disconcerting that people have forgotten how to have common sense. We are not meant to drink soda. We are not meant to eat highly processed foods with lots of additives. We are not meant to watch tv. We should be outside working the fields ie exercising. We should get sleep. It is sad that in this day and age we need science to produce some type of reductionist hypothesis to tell us what anthropologic history already knows.
We should drink water.
We should eat whole foods.
We should exercise outdoors.
We should get sleep. Doesnt everyone feel better with sleep?
We should take care of ourselves.
It is not to hard to figure out why we are fat.

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SpeedyB

03/02/09 at 1:39 pm

I agree with oracle99. Our ancestors ate food not processed chemicals. A little ChemoFood once in a while is ok. But most of the time try to eat REAL food that came from the ground and butcher.

When I see all those commercials saying that there food has this good chemical or this other beneficial stuff added in I laugh, all the good stuff they have artificially pumped into their food is the same stuff you can get naturally in a vegetable.

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rhepp018926

03/02/09 at 8:41 pm

The article completely missed the cause of the problem. Sugar is 99.9 % cause. Go shopping with a TypeII diabetic. Find 1 ceral in a large grocery that sugar is not higher than second in the ingredient list. Can't be done. Continue checking sugar levels on any proccessed product. Juices, bread, frozen proccessed diners. We watch fat, but not sugar. Check sugar consumption by country. US has more TypeII diabetics per capita than any other nation. Our pancreas can not utilize the amount sugar we are eating, restaurants are judged by how much sugar is in the food. How many meals per week are prepared in the home, cooked from simple, basic ingredients. 40 years ago we didn't have sugar as first or second in very many ingredient package lists. Take a typeII diabetic shopping. I am sure there is more than 1 on staff.

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1Sciguy

03/06/09 at 6:09 pm

It's not the amount of food, it's the type of feed.
Blame everything except the actual culprit - CARBOHYDRATES. There is no vitamin or mineral that the human body needs from fruit or vegetables. Eat fat, get lean, get healthy. The current obesity / cancer / heart problems have been escalating ever since the "don't eat saturated fats or red meat" era started. Cause and effect. Look at what has changed over the last 30 to 40 years and it all points to increased carb reduced saturated fats. We are eating less fat and more fruit and carbohydrates then ever before and we are getting fatter and fatter and less healthy.

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savagefan

03/25/09 at 12:09 am

Folks are ignoring the big fat elephant in the room. People gave up smoking and now they eat more. Donut shops are everywhere, people eat out of anger or frustration whereas 20 years ago they'd light up. Because smokers can't find a place to smoke anymore they eat fatty salty foods to help quell the nicotine cravings. We were sold a bill of goods about tobacco being so bad as an excuse to tax heavily. Now we'll have to tax food. I smoked for over 20 years quit for 4, got a little insight on this one. Had to work really hard to lose the flab I put on after quitting.

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nimo

04/14/09 at 2:17 pm

What about the pesticide that is used on corn that is suspected to the increase of estrogen level in frogs which made some males to become hermaphrodites.

Some of the frozen food that I occasionally buy gives you the option to heat it in a conventional oven even though the plate is made of plastic (That's CRAZY). I prefer aluminum to be used in an oven. Al can be easily recycled. I'm starting to hate plastics & our planet is covered by plastics. The most thing that pisses me off of why many people keep on drinking only from small plastic bottles when you can buy big refillable water containers for a much lower price!!!

Some obese Americans are so ignorant. They tell me that a whole bag of chips won't fatten you & they keep on eating it while they tell me they are dieting to lose weight!!!!

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Bebu

03/21/10 at 8:19 pm

I agree with oracle99.
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a6rp

09/24/10 at 4:26 pm

Society sure doesn't make it easy.
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