SFN Neuroblogging: Diets and binge eating

Oct 21 2009 Published by under Academia

It's the second to last day of SFN. Sci thought she was a grad student of boundless energy, but even she is beginning to feel...a little burned out. Posters, each one of the good and showing some seriously cool stuff, slide past her eyes. After a while you can barely remember what you just saw, even though you desperately want to, because you know you would never have seen it had it not been terribly cool. But at a conference this big, with so many people, it's hard to remain "on" all the time, to ask the brilliant questions, to give the perfect presentation.
But press on we must! SFN comes only once a year. It's like neuroscience Xmas! You have to soak in every inch of the experience. And even through your fog of exhaustion (and possibly your fog of hangover), there are some posters that stick out at you. Some that are elegant and interesting, no matter how tired you are:
*D. E. PANKEVICH, G. SMAGIN, T. L. BALE; Animal Biol, Univ. Pennsylvania, Philadelphia, PA; AstraZeneca, Wilmington, DE "Caloric restriction reprogramming of stress and reward neurocircuitry increases vulnerability to stress-induced binge eating"

As we all know, people in the US have a...concern with our weight. We might think we are too fat, or we are too thin, or that people in the US are too fat, or that we have unrealistic expectations of body shape and size. Regardless of which opinion you have, thinking about weight and diet takes up a LOT of American life, from the commercials we see to the amount we try to get to the gym.
And of course, Americans think a lot about diet. It seems that Sci cannot go a day without hearing about the Zone diet, the volumetrics diet, Weight Watchers. Sci herself writes down her food consumption, and worries far too much about what she's putting in to her body. It seems like everyone is forever going on a diet. I hear endless stories about the grapefruit diet, the Atkins, the Zone. I hear about the new Caloric Restriction phenomenon, where you are supposed to restrict your calories by 25% and prolong your life (something which is currently in clinical trials and was featured recently in the NY Times). Caloric restriction seems interesting. It might be able to prolong your life, to make you healthier. But is it all good? Are diets good? And what IS it about diets that makes you immediately crave those awful foods you shouldn't have, even when you know that you wouldn't crave them, if only you weren't on a diet?
Of course there's a way too look at this. In this case, the authors of the study used rats, and put them on a diet. Not anything too severe, just restricting them abut as much as someone in those new "Caloric Restriction" diets. But then, they took these newer, svelter rats, and exposed them to stress, looking at how they responded.
And the results...well. When rats are on a diet, and exposed to stress, it turns out that they eat their feelings. They binge eat a lot more than rats that had not previously been on a diet. This seems like a simple finding, but it shows something very important. It shows one of the reasons that "yo yo" dieting may be so harmful, and it shows one of the many ways in which stress can disrupt your diet. In particular, it wasn't just an increase in regular food intake in these rats, it was an increase in palatable food intake. These rats ate oreos (well, the rat equivalent of oreos, which is a high fat diet and very tasty to them) like they never ate them before. This shows that caloric restriction, though it might provide health benefits, may also be enough of a stressor to...stop your caloric restriction, making you more likely to binge eat and possibly less likely to stay on your diet.
Well, sure, you might think. Big news there. Of course when I'm on a diet, I crave oreos, because I know that I can't have them. Why do this in rats? Well, for several reasons. Doing this study in rats shows that the binge eating and cravings experienced in animals on a diet isn't a social thing for humans. It doesn't require conscious thought on our part, and in fact, may be due to some pretty basic drives. Not only that, when we study diet and binge eating in rats, we can look at their hormone levels, how they process food, and how they process signals of when to stop eating, which are things we cannot yet really investigate in humans. And finally, keeping humans on a caloric restriction is HARD. They tend to cheat. 🙂
So this relatively simple study could reveal, in the end, some very important things about how we process food cravings and how what we are currently eating changes our responses to simple things like stress. And it makes it more obvious that stressing out AND being on a diet is a recipe for an oreo disaster.

9 responses so far

  • Ron says:

    Interesting finding. In humans, though, there seem to be other stress fighting tactics at our disposal before resorting to ravaging the cookie jar.

  • Yes, stress and dieting seems to be a particularly bad combination. It not only makes you want to eat more, but it makes food that much more appealing. And yes, we humans have more tools to manage our feelings and our stress, but as they say "Life is hard . . . food is easy."

  • x-ine says:

    Interesting finding, but hardly surprising. Our bodies are programmed for storage (that good old thrifty genotype/phenotype hypothesis). You go on caloric restriction, the first thing you want to eat, especially in a stressful situation, is something with fat: an abundant source of calories. Not only does it supply with you a ton of energy, it makes you feel good. How many people do you know that drown their sorrows in a plate of carrots and celery?

  • leigh says:

    very cool, but i'm also not surprised. this makes me realize that i don't know nearly enough about the hunger/satiety circuitry and stress.
    this also somehow makes me feel better about not caring what i ate for the last month or so of grad school. 🙂

  • sunnystrobel says:

    Input is output when it comes to our food intake, too! What we conveniently seem to forget is the fact that our modern-day food input is of an utterly denatured , i.e. condensed & heat-damaged nature. No wonder that our satiety/stress circuitry is reacting un-naturally to this Frankenstein food intake; with our body system's panic button stuck on the emergency mode:" Keep trying! Don't stop eating! MUST find the right stuff!"

  • Dr Becca says:

    Interesting! I actually saw a poster today showing different, but related results: monkeys who'd been on long-term caloric restriction showed less stress reactivity, and less stress-induced neuronal atrophy. Now, apparently these monkeys had been on caloric restriction for 10-12 years, so maybe the idea is that if you eat healthily throughout your life, you'll be better prepared to deal with stress, but a short-term "diet" is stressful enough on its own to have adverse consequences.
    1Psychology, 2Wisconsin Natl. Primate Res. Ctr., 3Neurosci. Training Program, 4Med., 5Geriatric Res. Educ. and Clin. Ctr., Univ. of Wisconsin - Madison, Madison, WI
    "Associations of stress reactivity on neural atrophy and mitigation by caloric restriction"

  • Scicurious says:

    Dr. Becca: I didn't see that one! Could be the short term vs long term. Interestingly, a separate poster (that I cannot for the life of me remember the first author on right now) found that withdrawal from a high fat diet (without going to caloric restriction) is ALSO a stressor, so it might be a short-term thing about change in diet. I'd have to re-check the poster to see how long the rats were restricted.

  • Tom Edgar says:

    Presumably all the monkeys involved are caged. The stress of being confined is not measurable, some would be more so than others, then after a time the stress could be intensified or diminished, according to the make up of the individual animal.
    Being caged and fed inevitably leads to varying body mass differences.
    When will all the idiots with a PhD wake up. To paraphrase Mr McCawber. "If Energy in is greater than energy out accumulation results." You don't see any obese third word subsistence farming people, especially the women. Often enough getting the daily supply of water is exercise enough to keep down the weight. Look at the many overweight people who are unemployed. No work, coupled with junk food, with the only exercise a trip to the frig, or finger dancing the T V remote control. It really is a no brainer.

  • Scicurious says:

    Tom: I'm not sure what you're referring to. These were rats, not monkeys. And they were group housed to ensure play and that they were burning calories.
    And this wasn't about getting fat or thin, this was about the rewarding properties of palatable foods as a result of caloric restriction. So...yeah, not sure what you're talking about here.

Leave a Reply