TODAY   |  July 02, 2013

Junk food cycle: Sugar’s impact on your brain

A new study shows that eating junk food can make us crave even more junk food, kicking off a vicious cycle. TODAY diet and nutrition editor Madelyn Fernstrom discusses the study and the impact sugar has on your brain.

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This content comes from Closed Captioning that was broadcast along with this program.

>> ever wonder why you can't eat just one chip. eating junk food may make us crave more junk food kicking off a vicious cycle .

>> today diet and health editor -- excuse me. when you talk way mouth full of food. she is here to reveal the big impact sugar is having on your brain and what you can do about it. madeline, good morning.

>> good morning.

>> even this bag of potato chips it's the carbohydrates.

>> right. it's the kind of carbohydrates that make your blood sugar go up and down crazy. what is interesting about this study is you took out the factory of saying is it tasty food versus not tasty food and what was done is two milk shakes. they taste exactly the same. the thing that is interesting is we took taste and emotional content of eating out of this study to say if you put a different kind of carbohydrate high sugar versus lower sugar .

>> one is a high glysemic shake and the other is lower.

>> this is powdery.

>> right. in the lab people thought they tasted about the same. so they're made to simulate to act like a very sugary drink. sugary food or chips and sodas versus things high in fiber that keep your blood sugar stable and low and the interesting thing is there were not only changes in blood sugar but also changes in brain activity .

>> and you have imagines of the brain. this is your brain on sugar .

>> this is your brain on sugar . the brain of course will light up whenever all the red areas are lighting up and you would expect that with eating something. what you want to look at is right here. this area in the middle. in low sugary foods you don't see anything. but we move to high glycemic drinks, there's the red spot . looking at brain activity in an mri means you have more blood flow and more activity. if you do the subtraction and enhance the differences you see this red part in the middle is lit up. that's indicating a lot of activity in the brain center for reward and craving and even addiction. so this is the connection of saying if you give two drinks where they're different, high sugar and low sugar , with the high sugar junk food drink you get more reward and craving.

>> if i go into a restaurant and i want a milk shake , how do i know which one i'm getting?

>> this say personal choice. you can't do this -- this is a laboratory but translate it to what you'll eat, you'll get a bigger brain effect. you wonder i drink soda and can't stop drinking it. all the sugar makes me want to have more sugar there maybe a connection that's biological. when you have high sugary food you get a big increase in your blood sugar and then it dips. that can lead you to overeat. you wonder why. there's a component in your brain. we're hard wired for survival. we have to eat so in a way we need to make food part of something we do every day but now that the food supply has changed to a lot of processed foods without fiber that raise your sugar a lot we start to think maybe there's a biological behavior for this.

>> so take away the chips, take away maybe the shake, what are the foods we should be eating so we're not getting the sugar rush and then crash.

>> that's good.

>> avoid the sugar crash , have things that are going to be low in sugar and not processed. so think about not processed poods. things like eggs, lean meat, fruits or vegetables. a bowl of oatmeal is good if you get oats with slower release of sugar into your bloodstream and not high processed. white bagels and white rice . you don't hear people craving a rice cake . i have a great desire for an apple.

>> give me that bowl of broccoli. this is one more reason to say maybe there is a biological basis related to food cravings but it's not a case of my brain made me do it. if you have these problems and can't the cut down make a problem not to have them around.

>> it's a vicious cycle . once you get started you can't