National Geographic Daily News
Studio photo of rainbow-colored candies.

People have a stronger inborn preference for sugar than for fat, according to a new study.

  Photograph by Robert Clark, National Geographic

Cathy Newman

National Geographic

Published December 17, 2013

In the drama of obesity in America, fat and sugar have been fingered as indisputable villains. But which prime suspect is more sinister?

Eric Stice, a senior researcher at the Oregon Research Institute, and his colleagues fed milkshakes to 106 high school students while they were undergoing functional magnetic resonance imaging (fMRI) to see how reward centers in the brain reacted to shakes that were tilted in favor of either fat content or sugar content. The study, funded by the National Institutes of Health and published in the American Journal of Clinical Nutrition, concluded that sugar was the more nefarious of the two. We asked him to elaborate.

Tell us what's new about your study.

We're one of the first labs to give people food while in a brain scanner. We applied imaging to the reward regions of the brain and were able to say that sugar is able to grab reward circuitry and drive compulsive intake more than fat.

You indicate that the more sugar you eat, the more you crave. It sounds like we are talking about addiction.

It's absolutely like drugs of abuse. I would have never bet money on this. I still remember discussions with my mother. "If you feel bad … eat chocolate."

"Oh, Mom," I'd say. But as often is true, mothers are right.

Could you quantify the obesity problem?

About 60 to 70 percent of the population in this country is overweight or obese. We lose 300,000 people a year to it. It's mind-boggling compared with the other things we worry about, like terrorism.

What are the practical applications of the study?

If I were the mayor of New York, I would definitely go after sugar versus fat.

Which New York Mayor Michael Bloomberg did, of course, when he banned large sugary drinks.

Yes, but it was then overturned. [In March, Justice Milton A. Tingling of State Supreme Court in Manhattan struck down Bloomberg's proposed law limiting large sugary drinks one day before it was to take effect.]

What's the basis for our sugar cravings?

It seems to be the case that we have a stronger inborn preference for sugar. In early times, we died from not having enough food. The preference makes sure you get enough calories. There is absolutely no brake on overconsumption.

Why did you choose high school kids for the study?

We chose high school kids because the study is seeking to capture the initial neurological vulnerability factors that increase risk for future weight gain and whether weight gain and overeating energy-dense foods causes changes in reward circuitry. So we wanted to study kids before they show unhealthy weight gain.

On the good side, isn't consumption of fat down?

In the 1970s, we discovered that fat caused all those heart attacks. So there was a big push to cut it down. We've done a better job of cutting out fat. But we are overeating more, and we have replaced fat with sugar. There is sugar in foods that never had it before, like ketchup or spaghetti sauce. The food industry is selling what people like to swallow.

Unhappily, it seems we are constantly sabotaged by our brain chemistry. What's the answer?

We promote a gradual retraining approach, a gradual decrease of sugar.

Is all sugar created equal?

Carbohydrates include simple carbs—sugar—and complex carbs like fruit and whole grains. Simple carbs come in a lot of varieties, including sucrose, glucose, and high-fructose corn syrup. Even vegetables like carrots are high in sugar. So if you get 60 percent of your carbs from fruits and vegetables, that's great, because they deliver fiber—which makes us feel full—and vitamins and minerals. Simple sugars like soda, however, just give us calories, with no nutrient benefits.

What did you eat for breakfast today?

Special K. I'm a cereal eater. My wife says it has too much sugar. But I don't drink sodas.

(Read "Sugar" in National Geographic magazine.)

16 comments
Simon Yeats
Simon Yeats

Neither.. and both. It is the irresistible COMBINING of fat with sugar that processed foods provides, and is found nowhere in the natural world, that is the causing the obesity epidemic, not healthy fats or sugars on their own. Watch the BBC2 Horizons documentary on Fat vs Sugar this week (conducted by 2 identical twins), where one eats only sugar/carbs for a month, the other only fats. Both found just eating one and not the other for the month caused problems. You wouldnt eat a bowl of sugar, and likewise you wouldn't eat a bowl of double-cream, but mix them together.. !!

Richard Ham
Richard Ham

This is the same old problems as always... Please define sugars? I would bet that the sweetner in those milk shakes was HFCS which is clearly becoming a huge player in the obesity and diabetes problem; but all this time we accept ( shame on you NG for not seeking out the truth...) that people do studies and label something sugars when all sugars are not created equal!

Good science needs to be careful science.


Richard Ham
Richard Ham

This is the same old problems as always... Please define sugars? I would bet that the sweetner in those milk shakes was HFCS which is clearly becoming a huge player in the obesity and diabetes problem; but all this time we accept ( shame on you NG for not seeking out the truth...) that people do studies and label something sugars when all sugars are not created equal!

Good science needs to be informed science.


Ken Winemiller
Ken Winemiller

Great info for everyone to keep in mind for our daily diets based on our level of active life style

Tanya Zilberter
Tanya Zilberter

There's a serious evolutionary reason for our brain biasing toward carbohydrates (e.g. sugar) comparing with alternative energy carriers like fats. The matter is, animals survival depended on using ANY occasion to consume anything available and to put any surplus into depots for the rainy days. It just so happened that fat depots are huge and carb depots are tiny, one can survive only 1.5 days on the stored carbs while there are cases when human beings lived on their own fat, water and vitamins for more than one year. Because of that, our brain is so designed that it dictates to have as much carbs as possible. It never hurts in wild nature but it does in our "civilized" societies. You might want to read more, it's not that technical: http://goo.gl/AWzgfx

Charles Guo
Charles Guo

It is easy to focus on how much we eat and forget how much we burn. I have seen people drive round and round and round looking for a parking space as close to a shopping center as possible, instead of parking father away right away, reducing carbon emission and walking that additional 200 meters - a big deal? What lies behind that kind of mentality is all what we should ponder when looking at the issue of obesity.

Pratibha Garewal
Pratibha Garewal

Very interesting, but the cereal you eat is mostly sugar..........Not drinking sodas does not justify it.

Nate Jones
Nate Jones


You should be eating veggies and fruits, but when you eat those things, you generally get disgusted because you have been eating s*** food. I recommend making smoothies  full of fruit and veggies(WITH THE PULP!). Also regular fruits and veggies are not as vitamin rich as you would think, unless they are organic. 

Jennifer Flower
Jennifer Flower

I don't gt the connection between Special K and soda. But I agree that we consume far too much sugar on the whole.


Biju Toha
Biju Toha

It's absolutely like drugs of abuse" I am so shocked.  

Cow D'Alessandro
Cow D'Alessandro

Good information! There are many recent studies in popular media that show how eating greens and reducing your fat/sugar intake is healthier for you. Awesomeness. The other day I read on a Yahoo post about the 6 new rules of eating...veggies, I believe it was? One stated that we need to embrace the bitter veggies more. In particular they talked about a "Bitter Melon" which helps lower your numbers when consumed...for example people with diabetes. 

This is cool because my mother has always cooked this veggie in a chicken soup and always said it is a common vegetable for the Chinese. It has long been believed to help anyone with a virus/ disorder in the blood stream.   

Jean B.
Jean B.

Experientially, I think there is REALLY something to the addictive aspect of sugar consumption at least for some.  Leave it alone and one is fine.  Gratuitously ingest it and getting more is all you can think about.  Telling oneself that all evidence reveals the lie that more is needed does not help.  I wonder too if, for some, the sugar content of some alcoholic drinks is what makes some want to drink more.

Nate Jones
Nate Jones

@Jennifer Flower  The article is saying that Special K is a healthier way of consuming sugar, you will get  nutrient benefits, and will fill you up better than drinking empty calories in soda. 

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