Your brain, your food, and obesity

We recently hosted an article by scientist and guest blogger Stephan Guyenet that explained how certain foods—those with a high calorie density, fat, starch, sugar, salt, free glutamate (umami), certain textures (easily chewed, soft or crunchy, solid fat), certain flavors, an absence of bitterness, food variety, and drugs such as alcohol and caffeine—could trip reward systems in the human brain. Those reward systems, then, encourage people to eat more of the foods that trigger the reward. The result, says Guyenet, is a cycle that could be the link between the American obesity epidemic and the rise of highly processed convenience foods, designed specifically to trip those neural reward systems.

This theory, and several related theories, are increasingly popular in the scientific community. This week, there's an opinion piece in the journal Nature Reviews Neuroscience that looks at the strengths and weaknesses of these theories and talks about what research needs to be done going forward. It's kind of a space for researchers to step back and say, "Okay, here's what we know, here's what's not lining up with what we think we know, and here's what we have to do if we want to understand this better." In the context of science, an article like this isn't really a slam against the ideas it analyzes. Instead, it's meant to summarize the state of the science and share ideas that could either strengthen the case, or lead down entirely new roads.

Sadly, you can't read this article unless you have a subscription to Nature Reviews Neuroscience (or pay them $32 for single article access).

Luckily, Scicurious, a neuroscientist and an excellent blogger, has read the article, and has a nice run-down of what it's saying and what you should know. Some of the ideas being discussed here overlap with Stephan Guyenet's research. Some don't. But this is connected enough that I thought you guys would be interested in reading more and getting more perspectives on this issue. Let me make this clear, though: Guyenet isn't doing bad science. As with a lot of scientific research, there's often more than one way to look at the same data. Scientists can disagree without one person having to be all-wrong and another all-right. In fact, having different scientists working on the same subject is a key part of getting the facts right.

As you read, you'll notice that an important place where Scicurious' perspective really differs from Guyenet's is in terms of connecting the idea of "addiction" to certain foods back to the idea of an obesity epidemic.

...is there a place for food addiction? The authors think so, and I am inclined to agree. However, it needs to be much more stringent than the current model of food addiction that many people want to embrace (the idea that sugar makes you addicted or that being overweight means you have a problem). Changes need to be made.

First off, it's important to separate food addiction from obesity. Binge eating does not necessarily mean you are overweight, and being overweight does not necessarily mean that you binge eat. Ranking by BMI is not going to work.

Read Scicurious' full post.

(Via the illustrious Ed Yong. Image: Fabio Berti, Shutterstock)

Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.

Maggie goes places and talks to people. Find out where she'll be speaking next.

MORE: addiction • Food • neuroscience • obesity • research • Science

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The Snowden Principle

Mari Harju

in b4 fat hate and pseudoscience that happens invariably in any article that touches on the subject of fat.
- marilove
  
  Just eat less and work out more! That’s it! It’s that simple! No other information needed.
  
  And if you have trouble losing weight, you’re a lazy fat ass and should be ashamed.
  
  (/s)
  - Mari Harju
    
    Except that is not true.
    - Ipo
      
      marilove knew that.
      Your browser doesn’t display sarcasm tags?
      - Mari Harju
        
        It is hard to take sarcasm on a subject where perfectly reasonable and intelligent people will suddenly turn utterly bigoted and insensible.
    - marilove
      
      Yeah, sarcasm. :) But I get ya. It’s hard to tell sometimes, because people are assholes.
  - MikeKStar
    
    Simple, maybe – Easy….not so much.
    
    Food companies purposely promote food addiction by deliberately altering the properties of food to make them more pleasurable to our brains. It truly is an addiction – only people don’t realize they’re addicted.
    
    Adding salt, sugar, fat and other chemical additives trigger dopamine responses very similar to narcotics. This makes it harder for us to resist the urges to eat more and numbs the signals to stop when we’re full.
    
    Shaming the obese and calling them a lazy fat ass is exactly the wrong response and is counter-productive. Attitudes such as yours only contributes to the cycle of obesity described in the article.
    
    A recommended book that describes this topic in easy to understand detail is “The End of Overeating” by Dr. David Kessler. A very excellent book. The chapter about the restaurant chain Chili’s will make you want to vomit.
    - marilove
      
      Sigh. I didn’t think my sarcasm was THAT off!
      - MikeKStar
        
        Sorry…yeah. It’s hard to recognize sarcasm sometimes on emotionally charged topics such as this.
      - Antinous / Moderator
        
        Maybe you should edit in an addendum.
    - elix
      
      Carbs also appear to delay the “I’m full” mechanism from doing its job for even longer than it already does (around 15 minutes after your stomach is actually sated).
      
      And what’s the base of the Food Pyramid? 9-12 servings of yummy yummy starchy carbs a day. (No, I’m not going zero-carb on people, but is a loaf of bread a day a good idea?)
  - Ted Brennan
    
    Marilove, try some compassion you sound like Marihate.
    
    Also If the scientists are arguing over conclusions that are not that simple, there is a very good chance that they have already discounted your simple hypothesis for very good reasons. I am just guessing that you are probably speaking in ignorance of the scientific debate, that you have just been too intellectually lazy to educate yourself before making simplistic inane and downright mean comments.
    
    Maybe next time you should start there.
    - elix
      
      Woooooooooosh
    - marilove
      
      LOL, dude. I was not speaking out of ignorance of the scientific debate. I was speaking sarcasm.
      - Ted Brennan
        
        yep, elix has it right. Woosh. Went right over my head. Apologies, I obviously didn’t see the sarcasm
    - marilove
      
      It’s okay; you weren’t the only one. And I have been guilty of it myself. Haha. Anyway, your points are spot-on, anyway, as were the other replies — all full of good information. So it was worth it!
  - http://www.facebook.com/people/Tim-Quinn/528943941 Tim Quinn
    
    for the purposes of the following dialogue please accept the above post as the proxy we need it to be. It will now serve the purpose of polarizing the conversation despite the authors attempt to soothe the zeitgeist with some backhanded humor.
    
    So it goes . . .
Ted Brennan

So Guyenet does not have a theory in scientific sense, he has a hypothesis that is worth further study. It is scientists like Guyenet who make it a problem to teach things like evolution. Unlike those theories, he puts the cart before the horse. There is not the complex scientific support to back him up, as this article shows. His extravagant claims have not been accompanied by great overarching science. Some science, yes, but he consistently over reaches compared to his current evidence.

Frankly the support for his position isn’t there when it comes to obesity. But of course, even Guyenet will walk it back to the science when questioned, but not when putting forth his program of what policies people and society should take based on his hypothesis. Sadly, for nutrition and diet this is pretty par for the course. Someone gets a limited result and its off to the races.

Thankfully, there are people who will do the scientific reviews like in Nature. Good science is the way forward. Guyenet frequently does good science in his lab work but overreaches in his conclusions. That is the difference in the end between having a good tested hypothesis and a broader theory supported by many tested hypothesis. He has only done one section of the work.
elix

This is essentially the entire thesis and point of The End of Overeating by Dr. David Kessler, former FDA commissioner. He doesn’t go deep into the food chemistry from a scientist angle, but basically the book is an exposure and explanation of how the modern food industry has poured untold billions into R&D to short-circuit the reward system for the purpose of pushing more product.

Disclaimer: I have no connection to Dr. Kessler, I’m just a fat guy trying to become less lardassed and I’ve read the book. Losing weight healthily is slow-going.

Edit: Oh, hey, MikeKStar got there before me.
http://www.facebook.com/people/Tim-Quinn/528943941 Tim Quinn

There is also a distinct fork in the conversation, don’t you think? The threads persist and intertwine in a quite amusing way.
- PinkWithIndignation
  
  Oh, the fork puns one could make. Please don’t. Except this one: no one’s putting a fork in this line of scientific inquiry, it’s not done yet.
Philip Terry

Ted Brennan wrote: ”So Guyenet does not have a theory in scientific sense…. It is scientists like Guyenet who make it a problem to teach things like evolution. ”

Where is this stuff coming from? I don’t get this at all from reading Dr. Guyenet’s writings. Quite the opposite. Science and evolution are at the core of his writings. I don’t see any principles here from Scicurious or Ted Brennan that Stephan would disagree with (other than their characterizations of him). Seems like Stephan is being mistaken for straw men that are his antithesis.
- nostar
  
  I completely agree; to my mind Guyenet’s writing on his blog has mostly been exemplary case of careful exploration f competing data, but also trying to find practical conclusions.
HarveyBoing

Of course pleasure responses from consuming calorie-rich food is related to the obesity epidemic. Duh.

But what’s the real issue here? It’s that these calorie-rich foods, and especially those lacking in actual nutrients, are so much less expensive than food that’s good for you. In large part due to the screwed up subsidy system that’s led to corn and soybeans being the foundation of the bulk of the nation’s food supply system.