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Rational Or Emotional? Your Brain On Food
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Scientists are working to understand what hormonal and physiological cues in the body lead the brain to respond to food emotionally.
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Scientists are working to understand what hormonal and physiological cues in the body lead the brain to respond to food emotionally.
Willpower plays a role in dieting. But keeping the weight off after you've lost it? This is where our physiology can get in the way. Research suggests that hormone shifts that follow weight loss play a role in changing the way our brain responds to food.
"After you've lost weight, you have an increase in the emotional response to food," says Columbia University Medical Center researcher Michael Rosenbaum, who studies the body's response to weight loss. He says you also see "a decrease in the activity of brain systems that might be more involved in restraint."
And there's another factor making weight loss maintenance tough, too: a slower metabolism. When you lose weight, the body adapts to conserve energy, so it just doesn't need as many calories.
One of the hormones that play a role in controlling appetite in the body is called leptin. After significant weight loss, leptin levels drop. This seems to signal to the brain a need to seek more food.
Rosenbaum and his colleague Joy Hirsch, a neuroscientist at Columbia University Medical Center, designed an experiment to better understand the relationship between the brain, leptin and weight-loss maintenance.
They recruited overweight volunteers who agreed to a calorie-restricted diet aimed at shedding 10 percent of body weight. Using fMRI scans, the researchers looked at how the volunteers' brain responses to seeing food changed after weight loss.
Still Emotionally Attached
During their study, Hirsch and her colleagues found some interesting patterns of neural activity in their volunteers after they'd lost weight.
For instance, there was more blood flow to areas of the brain known to be involved in the emotional control of food intake, such as the brainstem and parahippocampal gyrus.
But here's the fascinating part: When they restored leptin to these volunteers by giving them injections of the hormone, the brain response changed. When they saw food, there was more activity in brain areas associated with conscious decisions.
"It's a feedback mechanism," says Rexford Ahima of the University of Pennsylvania. Leptin signals the brain; when there's a deficiency of the hormone, the areas of the brain associated with reward-seeking become more active.
This evolutionary programming is out of sync with what's healthiest for our bodies. The signal evolved over thousands of years when food was scarce. It was the brain's way of telling the body to seek food and protect fat stores. Many people — particularly those who are prone to gain weight easily — have retained more genes that program us to seek food.
As for the role of leptin, researchers say it's clear that leptin is not an anti-obesity hormone — it won't help you lose weight.
But Ahima says the most recent research suggests that leptin — or drugs that would stimulate leptin signaling — could potentially facilitate the maintenance of weight loss. So far, this has only been tested in experimental trials.
My Brain's Response To 'The Food Parade'
Allison Aubrey/NPR
Researchers tested subjects, including NPR's Allison Aubrey, by showing them a mirror image of the real foods displayed above. They compared their brain response to food with the brain activity when it viewed mundane household objects.
The researchers invited me to their lab at the Neurological Institute at Columbia to see exactly how the experiment works. Curious about how my brain would respond to food, I agreed to an fMRI scan.
As I lay in the scanner, I watched through a mirror as research assistants passed all kinds of foods — from carrot sticks and apples to Hershey's Kisses and cookies — through my line of sight.
"Think of it as a food parade," explained Hirsch. After 20 minutes of watching food, the researchers began analyzing my brain responses.
"You will see a very specific circuit in your brain that's associated with the appreciation of foods," explained Hirsch.
Hirsch says the patterns in my brain images were similar to those of test subjects with restored leptin. She pointed to areas in my parietal and frontal lobes that had activated as I watched the "food parade."
"This is the executive part of the brain," says Hirsch. "You're responding like somebody in a homeostatic [stable] state." This means that when I saw the images of food, my brain activated decision-making areas, and there wasn't nearly as much activity in the emotional, reward-seeking parts of the brain. Hirsch also pointed out that my brain showed lots of stimulation in areas related to visual processing.
Courtesy Columbia University Medical Center
Researchers spotted drastic difference in Aubrey's brain activity when she looked at foods, as compared to mundane objects like a cell phone. Areas of the brain associated with visual stimulation really lit up.
Of course my brain response could change. The brain images captured just a snapshot in time. But it was fascinating to see that I didn't have a very emotional response to food. By comparison, images they'd shown me of mundane household objects — such as a cell phone — didn't evoke nearly as much activity in the areas associated with executive function or visual processing.
Hirsch and Rosenbaum's findings were published in the Journal of Clinical Investigation. They're now working on follow-up studies to figure out if people's behavior maps with what they're seeing in brain scans.
"It's a work in progress," says Hirsch. But she thinks this research is showing that our physiology tends to set the brain in one of two modes:
The "regain" mode, which nudges us, emotionally, to seek food. Or the "retain" mode, which helps us maintain a steady weight. Researchers are following up with more studies to see if people's eating behaviors mirror their brain response to food.
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Jo R (Jomr) wrote:
@Prasad Dharmasena (pkd2034)
The eating habits you describe are very unhealthy (I can say this because my BMI is 22.3 and has never been above 25). After 5 hours without food your body goes into starvation mode. It will retain anything you eat as fat and it will consume your muscle as well as fat for energy. You may be losing weight but it is not making you healthy. The loss of muscle mass will only make it more difficult to keep the weight off. A balanced diet high in fruit, vegetables, beans and whole grains in combination with cardio and strength training is the only means to get and stay healthy. What you describe sounds like an eating disorder, I would highly recommend that you find a doctor or nutritionist that you are comfortable with.
Wed Feb 24 19:01:44 2010
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Russ Lane (RussLane) wrote:
I would love if the piece also addressed real-life maintainers who instinctively know what these scientists are finally determining themselves.
Life, post-weight is something that is often criminally overlooked, and I'm grateful that Ms. Aubrey is raising awareness -- few stastistics address weight regain in the obestiy debates, and for all the support available once you've lost weight, it often feels you're thrown to the wolves when you hit goal and somehow "cured."
More to the point of the article: after losing 250 pounds as a food writer, I learned to take a weakness (emotional eating) and turn it into a strength. In other words, make these emotional response work for you. For me, the answer was finding gourmet twists on standard understandings of healthy cooking.
Not only if your food healthful, it's emotionally engaging, inspiring even. And going from eating large pizzas on your own to making mole-crusted lean pork with a sour cherry mustarda? That's power.
Great piece and thank you so much!
Best,
Russ Lane
Second Helping: Food & Life, Post Fat Pants
www.secondhelpingonline.com
Wed Feb 24 12:58:19 2010
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Beth Hartford DeRoos (MotherLodeBeth) wrote:
C Star (cstar) wrote: I wonder how this study's results might differ if it were done in a country, with a culture that relates differently to food. For instance, it seems that culturally, the people of France and Italy have close emotional ties to food, connecting more closely to the land and with family. Would their brain function portray this cultural characteristic?
Because of family I am very familiar with France and Sweden, and know that food isn't a 24/7 focus like here in the states. And the amount of junk food is small. And you don't see people grazing all day. Its so sad that we see very few healthy foods advertised, but foods that are geared to instant gratification with no satisfying of hunger. We eat French and Swedish foods and servings in our home. Small servings. And we work at being physically active. Something I notice folks who live in the city and very rural areas understand. And drinking more water, getting enough sleep and not being so negative. Makes one wonder what effect media has on the human condition.
Tue Feb 23 00:22:11 2010
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m fellion (michael1) wrote:
Prasad, you say eating every third day worked for you? Soounds to me just like what probably occurred when we were hunter gathers. I am going to try it myself.
Mon Feb 22 19:06:15 2010
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susan hoo (whatthe) wrote:
If your physiologic needs are met, then the response to food is psychological - with likely emotional overlays from associations with food in general and specific foods specifically. If food (or certain foods) were used as punishment (have eat veg before any sweets) or rewards, that will play into those limbic and reward centers.
Your response, or motivation/rationale with the weight loss also plays a significant role in response. Did you say "none of this particular food" or "only if conditions a&B are met," or did you merely limit portions or times of eating?
The results would differ mightily in an infant, a toddler and so on, and in different socioeconomic strata and cultures.
Mon Feb 22 15:02:24 2010
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Prasad Dharmasena (pkd2034) wrote:
If you stay off food for the entire day (ie: only coffee, tea, and water) then it is easy to tell yourself "don't fall off the wagon" for the remaining few hours. And, the second straight day becomes much, much easier. Of course, don't skip your 40min cardio or the sit-ups and chin-ups. The third day's only meal is your feast, of course. {grin} Worked for me to lose 20%, but YMMV; and, "they" tell me this isn't healthy. Ever notice that people who tell you dieting isn't healthy have ... um ... "unhealthy" BMI numbers?
Mon Feb 22 14:05:53 2010
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Ilya Rachman MD PhD (trimdoc) wrote:
Great story! Biology of eating is one of the most relevant subjects today, since it's the main health scurge and the money pit in our society.
As a weight loss doctor, I must add one point - until access to low-calorie foods becomes just as easy as high-calorie foods, we will ALL continue to struggle with weight, weight-related medical problems and costs. Effective weight loss techniques, as many have commented above, boils down to reshaping your environment and not relying on will power alone. For example, if you stuff your cubbards with veggies and not potato chips, at 9pm you will be "stuck" with a 30 calorie "treat" and not 300!
Mon Feb 22 12:15:14 2010
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C Star (cstar) wrote:
I wonder how this study's results might differ if it were done in a country, with a culture that relates differently to food. For instance, it seems that culturally, the people of France and Italy have close emotional ties to food, connecting more closely to the land and with family. Would their brain function portray this cultural characteristic?
Mon Feb 22 11:10:35 2010
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JamesClifton Spires (Jdaddy) wrote:
Because of lifestyle changes --- becoming single again, change in income level --- I stopped eating out so much. Since September, I've dropped at least 20 pounds and gone down two pants sizes. I attribute this mostly to doing my own cooking, keeping an eye on the budget, restricting the impulse buying and when the weather is halfway decent, going for regular walks in the local National Park.
I also think about double-cheeseburgers, French fries with gravy, pancakes with eggs and sausage, Chinese food buffets and pizzas all the time --- all of which have now become "special occasion" foods rather than diet staples.
What's interesting, though, is when I do allow myself the rare opportunity to indulge in such items --- usually when one of my adult kids wants to take me out to dinner --- I've found they don't taste as good as I remembered. I also find that I can't eat the big servings like I used to.
What's changing, of course, is me. My body has adapted to smaller portions and there's a psychological feeling attached to eating out as I realize that if I stayed home, I probably could have cooked at least two meals for the price of what a restaurant meal costs. That's an appetite killer right there.
Mon Feb 22 10:10:32 2010
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Jay M (bachdog) wrote:
"And there's another factor making weight loss maintenance tough, too: a slower metabolism. When you lose weight, the body adapts to conserve energy, so it just doesn't need as many calories."
This is true only for people who lose weight without exercise (regular physical activity). Exercise makes the metabolism work faster, not slower. Only people who lose weight (very slowly) by changing their eating habits only and not by exercising might have a slower metabolism. Sedentary people have the slowest metabolisms--their bodies gradually become very good at storing fat.
Mon Feb 22 09:29:57 2010
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