Tuesday, April 23, 2013

Why We're Obese: An Intro to Food Reward

Obesity is complex. I think we all know that at this point. There is no one reason why any of us become obese; it's a combination of several factors including genetics, physical activity, hormones, calories, fat, carbs, junk food, and much, much more. We can of course say that we get fat from eating more calories than we expend, that's a fact... but that doesn't tell us anything about why we're consuming more food than we need. Likewise, we don't truly know the best way to lose excess weight. We need to eat fewer calories than we expend, duh. But we have to worry about complicated things like hunger, willpower, and cravings... and why it feels like your body just wants to hold onto that extra fat.

Enter: Food RewardI've touched on this in the past but I haven't given it a proper explanation.  I first heard of the concept via Stephen Guyenet a couple years ago, as most people in the ancestral health community did.  It's taken me a while to fully warm up to it and truly understand it, but I'm now convinced that this is a major reason, perhaps the major reason, for the obesity epidemic.  Allow me to explain.

The Reward System
Our brains contain a "reward" system that is critical to our survival.  Actions that promote our survival are reinforced by the brain by making us feel good... this makes us want to do them again.  For example, running around in the sun playing frisbee makes us feel good; the sun is good for our health (in moderation), physical activity promotes fitness and survival in the most primal sense, and it gives us a sense of community and kinship with our friends.  Our brains tell us that playing frisbee in the sun is a good thing, and we're likely to do it again in the future.  But the reward system also works the other way, discouraging actions that harm us.  If we pick up a baking dish out of the oven with our bare hands, we'll burn our skin, and so our brains send a very strong signal for us to STOP (pain).  Addictive drugs essentially hijack this reward system.  Heroin, for example, will bypass the environmental sensory aspect of the reward system and latch on to the receptors in the brain.  Drugs like these provide a super strong stimulus, hence they are reinforced by happy feelings, and you'll want to do it again and again until you become addicted.

The same goes for the food we eat.  We do need to eat to survive, after all.  Something sweet, tender, and high in calories?  Rewarding.  Something bitter and fibrous?  Not so much. Think of humans in the wild, or in hunter-gatherer times... the foods that best help us survive elicit the strongest reward signal, and we're motivated to eat more. There are several qualities of food that have been found to be inherently rewarding (1):
  • Fat
  • Starch
  • Sugar
  • Salt
  • Meatiness (glutamate)
  • The absence of bitterness
  • Certain textures (soft, crunchy, liquid)
  • Certain aromas (fruits)
  • Calorie density
  • Variety

The Reward System in the Modern Food World
Now that's all well and good for survival.  This reward system works perfectly in a natural setting to guide us in what to eat.  We're perfectly happy eating fresh fruits, meats, potatoes, veggies, etc., and we'll eat just as much as we need until we're full and we stop.  Even 50 years ago, we ate mostly natural, unprocessed foods, we ate as much as we wanted until we were full, and we stayed lean.

Since the 1950s, the average American has increased his/her caloric intake by about 500 calories.  In that same time period, the prevalence of obesity has nearly tripled (2). 

What changed?  The food industry figured out how to sell more food to the same number of people, something that was previously thought to be impossible.  Once they figured out that they could make food that is so appealing and rewarding, combining all of the factors listed above, that we would continue eating it regardless of our hunger cues... the game was over.  They're preying on our most primal of instincts.  And we can't stop, because our bodies are telling us to keep eating.  We're designed to keep eating.  It's not our fault.  Sounds a lot like heroin doesn't it?

How exactly do they do this?  Let's count.

  1. By combining fat, sugar, and salt with calorie density, crunchy, and chewy... The Oreo, for example.
  2. By drizzling sweet, salty, fat condiments on top of already sweet, salty, fatty foods... TGI Friday's Jack Daniels Grill.
  3. By increasing portion sizes... McDonald's burgers.
  4. By adding MSG, a meaty flavor, to already hyperpalatable snacks... Doritos, or even worse, that ridiculous Doritos Locos Taco.
  5. Through convenient product placement... Candy bars at the checkout line.
  6. By adding sugar, salt, and fat to already-addicting caffeinated drinks... Starbucks anyone?
  7. By marketing junk food to children... How cool is the Kool-Aid man?
  8. By offering a variety of food from all around the world in unlimited quantities... Home Town Buffet.
  9. By capitalizing on the drunk munchies at the local diner... Disco fries.
  10. By putting Coke machines everywhere... Everywhere...

This is deliberate, it's no accident.

Just look at that shirt... God he's cool.

The Conclusion
The goal of the food reward system is to get us to eat enough real food to satisfy our nutritional needs, no more and no less.  The reward system is NOT designed for processed, hyperpalatable food.  We are designed to eat sugar, fat, starch, and salt, but not excess sugar, fat, starch and salt... and definitely not at the convenience and in the sheer quantity that we're getting it in today.  

I know food companies need to make a profit, but something's gotta give.  The cost of the obesity epidemic is immense... we can't keep this up.

The solution isn't sexy. Just eat real food. Call it Paleo, call it ancestral eating, call it what you will. Just opt out. Get back to basics and eat real food again. Take your health into your own hands and keep it real. I'm out.



    I enjoyed this. Also, I think you have that same shirt as the kool-aid man.

    I think eating this way is a lot sexier than eating candy bars.. just sayin. It doesn't get much sexier than bacon.

  2. Good post and I'd also add teachers and parents giving candy as a reward. http://kyhealthykids.com/2013/04/15/food-as-reward-infographic/

  3. I agree. Food reward goes so much further than hyper-palatability too.

    When I was a kid I remember sleeping over my grandmother's house a few nights a week. I would sit down at the plastic covered table and flip TV channels with the plastic covered remote as she fed me a bite of pizza and then a bite of banana. Then I'd take a swig of cranberry juice mixed with orange juice. When I got to the point I couldn't eat anymore, she started telling me a story and I finished the banana and another slice or two.

    I think that served the basis of my desire to stress-eat now. A return to the good ol' days of grandma's house & banana pizza.