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?


High-Sugar Diet Study
Here's another interesting study, again in Stephan's words... "Volunteers were restricted to a bland liquid formula that was high in sugar, but were not asked to restrict calories.  While lean subjects maintained a normal calorie intake and body weight, obese subjects experienced a greatly reduced appetite and rapidly lost weight, with one man losing 200 lbs over 255 days (30)."  Incredible, right?  You would think, if sugar were fattening, that restricting subjects' diets to only a high-sugar drink would make them fat.  Except it didn't.  Much like the high fruit diet study, lean subjects maintained their leanness while overweight subjects effortlessly lost weight until they reached their ideal body weight.

Clearly there's more at play here than just "sugar is fattening".  It's not.  Sugar on its own does not make you fat.  Not saying it's good for you though; it's still completely devoid of nutrients and it won't contribute anything positive to your diet.  Plus refined sugar promotes some nasty chronic health outcomes like the metabolic syndrome.

How does sugar make us fat?
So what does make us fat then?  Why do people who eat sugary junk foods like sodas and candy bars gain weight?  They're consuming too many calories of course, but why?  Why are they eating more calories than they need?  Aren't people supposed to stop eating when they're full?

Two words... Food Reward.  Sugar on its own may not be fattening, but when you add sugar to food, it makes that food a hell of a lot more palatable and rewarding.  Take chocolate for example... how much 85% dark chocolate can you eat??  Probably not a whole lot.  But how many Oreo's can you eat??  The whole bag.  You know it's true.  Highly rewarding foods like this signal directly to your brain and tell you to eat more, resulting in overconsumption and weight gain.  The same effect can be achieved, by the way, if you add fat, salt, flavorings, MSG, etc. (probably all of which are added to Oreo's and other similar shit-food).  Sugar is just one tool at the food industry's disposal aimed at getting you to eat more.  Sugar on its own... not fattening.  Sugar added to processed junk... fattening.  Context matters.

I know this food reward concept may be difficult to wrap your head around; you're probably thinking "well duh, of course people will eat more if it tastes good".  But there's more to it than that; these highly palatable junk foods literally activate the reward centers in the brain like a drug does, and they completely screw up your normal hunger/satiety signals.  It's sort of an abstract concept, but if you're interested I highly recommend this book here called "The End of Overeating" by Dr. David Kessler for more info.  Or you can check out Stephan's food reward blog series at Whole Health Source.  Anyway, back to sugar.  To sum up my point with this post, I will quote Stephan again.  I don't write any of my own material anymore...

"The controlled human studies once again suggest that sugar and fructose are not inherently fattening, but that refined sugar can cause body fat accumulation when it's used to increase the palatability, reward value and energy density of food and beverages."

I hope I expanded your brain today.  If you found this anywhere near as interesting as I did, congratulations... you might be a nerd too.