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 Reward.  I'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.

Causes of Obesity: Food Variety

So I had this new idea today while sitting in class.  We were talking about food palatability and how modern food is "hyperpalatable"... this just means that it is extra salty, extra fatty, extra sweet, and overall just more pleasing to eat than food of the past.  (I've talked about this before 1, 2, 3, 4).  And I started thinking... there are like a million different reasons why Americans are so obese.  Why don't I start exploring each one individually on my blog??  So that is what I will be doing.  Starting now.  Maybe ironically NOT starting with hyperpalatability of food... although it's a related topic.  Today our cause of obesity is unconventional, one you probably haven't thought of.  And you all know how much I like bringing you a fresh perspective and new way to think about something.  So without further ado...

Cause of Obesity #33162:  Food Variety

Why do we eat?  Is it because we're hungry?  Partly.  But there are other reasons too.  Don't even act like you don't know... boredom, convenience, stress, depression, happiness, celebration, social pressures, societal expectations, just because it's meal-time...  the list really does go on and on.  Because of this, researchers have divided eating into two categories:  homeostatic and non-homeostatic eating (1).

Homeostatic eating:  eating is driven by a true need for energy
Non-homeostatic eating:  eating is driven by factors other than a need for energy

Pretty simple really. 

So how does variety fit into this?  Easy.  You can only eat so much of one food.  In fact, variety in food is one of the major factors driving how much you eat, whether you notice it or not.  There are even diets designed for weight gain based around this principle... take the cafeteria diet for example.  Allow humans (or rats) easy access to a high variety of food and they'll gain weight.  In contrast, give someone a restrictive diet that lacks variety and they inevitably eat less and lose weight.

What Christmas Cookies and Heroin Have in Common

First of all, Merry Christmas to everyone!  And if you don't celebrate Christmas, then you know what I mean... don't be all hypersensitive and get offended.  The way I see it, if someone said "Happy Hanukkah" to me, I wouldn't take offense, and I'd wish them a Happy Hanukkah back.  When someone wishes you a happy-anything, why would you inject negativity into the situation?  Besides, Christmas has become more than a Christian holiday; I don't really consider myself a Christian to be honest (at least not in the traditional sense), it's just a cultural thing to me, and it's a tradition in my family.  So that's my take.  Of course, this has nothing to do with today's post, but screw it, I needed to get that out there.  Stop being so sensitive.  I'm only disrespecting you if you take it that way. 

So today, I just want to briefly talk about something I read about on Whole Health Source about food and opioid receptors.  The opioid receptors, just like they sound, are the receptors in the brain that are hijacked when you take drugs like heroin.  They're responsible for the addictive nature of drugs.  This "reward" system is what calls at you to have a cigarette, snort some coke, or inject some heroin.  And the more you do it the more you want it.

But this wiring in your brain has a practical purpose; it's not there solely to make sure you end up living in a cardboard box with nothing but your dog and your needles.  Although it's pretty good at that too.  But it's there to encourage behaviors that promote your survival, so that you'll continue to do them.  Like eating food for example.  Obviously, eating is important for survival, so this reward system encourages us to eat foods high in calories and important nutrients.  Eating grass wouldn't get us anywhere; there's no calories for us in grass, and that's why you don't crave it.

Why It's So Important to Avoid Holiday Weight Gain

It's that time again, folks.  The best time of the year.  Thanksgiving, Christmas, and New Years... the holiday season.  There's just nothing like it... turkey dinners, Christmas trees, the snow, the gift of giving, the time spent with family.  I look forward to it every year.  But step inside the psyche of any health-conscious person this time of year, and you may find a war zone:

"I love apple pie, but I don't want any.  I don't want it.  It goes right to my butt.  God, look at it... it's gawking at me.  Ahhh okay I'll have a slice.  ONE slice.  Just one slice and I'll stop.  This is the year I keep my weight under control during the holidays.  Oh god that was good.  Shit girl, give me another.  This is better than sex, oh my god.  The apple pie god.  I love him, he who created apple pie.  Screw butt fat, whatever.  Men like big butts anyway... they cannot lie."

Right?  We all know the holiday season presents a problem.  Excessively yummy food + great people + alcohol = weight gain.  It happens every year... and come the New Year?  Resolutions abound.  Gyms explode with new members, we eat less, and we try to right the wrongs of the past few months.  But, as anyone who has done this probably knows, that weight doesn't come off with the same ease at which it was put on, and rarely does it stay off.

And that's the point of this post.  I want to explain to you why that weight won't stay off, and why, consequently, it's so important to prevent the weight gain to begin with.  Saddle up partner...

Bacon Ice Cream, Counting Fat, and Shut the F Up

A couple of things have been irritating me on this Thursday morning.  First, the clouds.  Today was supposed to be sunny, at least according to my iPhone.  I was planning on spending the morning outside and soaking up some vitamin D.  Thank you iPhone for lying to me, and thank you clouds for being sons of bitches.  Secondly though, is Burger King's new Bacon Ice Cream Thingy.  Who in holy hell came up with this thing?  Bacon on ice cream?  That's retarded.  But do you want to know what's even more retarded?  The author of that article's concern about the fat content of the Bacon Ice Cream Thingy.  Oh my god, 510 calories and 18 grams of fat!  That's even more than a bacon cheeseburger! (Her claim, not mine, that's a little hard to believe honestly.)  Sure, she mentions the 61 grams of sugar, but she stressed the fat.  They always stress over the fat.  And I'm sick and tired of it.  There's no reason for it.  Just shut the F up. 

You see, everyone's got this phobia of fat making them fat.  They think that if they eat the fat on that pork chop, or put butter on their potato, or drink whole milk, that they'll get fat.  That's not how it works.  Fat in the diet doesn't make you fat any more than other calories do.  In fact, natural fats are very satiating, and would probably even help you eat less and lose a couple pounds.  There are a lot of reasons someone might gain weight.  Eating fat isn't one of them.  Neither is eating carbohydrates or protein.  Eating too many total calories on the other hand... will get you nice and fat.  Focusing on one particular nutrient completely misses the bigger point.  What makes us fat is not carbs or fat per se...  but if I had to design a food to make you fat, I would design exactly this Bacon Ice Cream Thingy.  Are you confused yet?  I think I may have confused myself there.  The Bacon Ice Cream Thingy WILL make you fat.  But it's not because it has 18 grams of fat, or because it has 61 grams of sugar.  It's because it's loaded up with so much hyperpalatable goodness that you'll eat the whole frickin' thing even if you're not hungry.

Does Sugar Make You Fat?

Sugar is in the news lately.  If you haven't seen the 60 Minutes report on sugar, check it out.  It's worth a look, even if they're likely over-exaggerating a bit, as the media tends to do.  But anyway, that got my sugar appetite going.  Not for eating it.  I mean for learning more about it.  It didn't take me long to find this blog post on Whole Health Source entitled "Is Sugar Fattening?"  Very interesting article.  And a great question.  You'd probably expect that sugar is fattening, based on the conventional nutrition wisdom, but when you look deeper, you may be surprised.  Let's define "fattening".  If sugar is inherently fattening, that means that a diet high in sugar should promote fat gain even if we are still in calorie balance.  Right?  Or if that's not true, it must be true that a diet high in sugar causes overconsumption of calories, and hence fat gain.  Yes?  Either way... if sugar is fattening, then eating nearly all of your calories from sugar would surely make you fatter.  Let's take a look at some studies.

Google said it was sugar, but truly it could be cocaine.  Nobody really knows.

Almost-All-Fruit Diet Study
For the sake of time, and because Stephan put this better than I could, I'll simply copy and paste his words here... "a 1971 paper titled 'Physiological Effects of a Mainly Fruit Diet in Man' (29).  Subjects ate nothing but fruit (82% of kcal) and nuts (18% of kcal) for six months.  The diets were 52-65 percent carbohydrate (mostly from fruit sugar), 37-45 percent fat (nuts and avocado), and 5.6-8 percent protein.  These fascinating quotes sum up their findings:

A considerable number of the normal subjects claimed that their physical condition improved while they were on the diet.  Some were convinced that their stamina increased and that their ability to undertake strenuous physical tasks and to compete in sport improved.

From these figures it is clear that most subjects lost weight initially... After the initial loss, the weights of the subjects in group B leveled off at figures which corresponded more or less with the calculated theoretical normal weights...

A few of these who were mildly overweight, found this diet an excellent incentive to reduce, and consequently showed a greater decrease in weight than the others.  An interesting aspect of the diet was the tendency for the weights to level off more or less at the 'theoretically ideal' weight for the subject.  This may partly explain why some lost more weight than others."

Welp, looks like it's pretty clear that the sugar in fruit isn't fattening.  These folks ate an insane amount of fruit (not quite 30 bananas a day, but who's counting), and their weights just effortlessly settled into their "theoretical ideals".  I know a lot of people in the paleo world who limit their fruit intake for fear of over-consuming sugar and getting fat... maybe we should stop worrying about it.  But what about refined sugar?