Most of us have been tempted at one time or another by the lure of sugar. Think of all the cakes and cookies you consume between Thanksgiving and Christmastime!
But why are some people unable to resist that second cupcake or slice of pie? That's the question driving the research of Monica Dus, a molecular biologist at the University of Michigan. She wants to understand how excess sugar leads to obesity by understanding the effect of sugar on the brain.
Dus's interest in how animals control the amount they eat started with a curious incident involving her two Bichon Frise dogs. One day, Cupcake and Sprinkles got into a bag of dog treats when Dus wasn't around. The dogs overdid it.
"I couldn't believe that these two tiny, 15-pound animals had huge bellies for three days and they couldn't stop themselves from eating," she recalls.
Dus was already an expert in fruit fly genetics, so she decided to study flies to see if she could unravel the puzzle of how the brain controls eating behavior.
Her lab has a working hypothesis. Dus believes a diet high in sugar actually changes the brain, so it no longer does a good job of knowing how many calories the body is taking in. She thinks there are persistent molecular changes in the brain over time – changes that pave the way for excessive eating and eventually, obesity.
"Perhaps it has nothing to do with will, and a lot to do with biochemistry," she says. Just as scientists in the last century showed there was a link between smoking and lung cancer, Dus thinks she can find a link between an early exposure to a diet high in sugar and obesity.
Dus' ideas have been attracting attention. She's just received a $1.5 million, five-year New Innovator award from the National Institutes of Health. It's a new kind of grant aimed at "exceptionally creative, early-career investigators who propose innovative, high-impact projects."
She's also a Rita Allen Foundation Scholar, a program that is intended to help young investigators "establish labs and pursue research directions with above-average risk and promise."
Dus is taking a multidisciplinary approach to understanding how sugar affects the brain. When I visited her lab at the University of Michigan, she took me into a room where Christina May was studying individual cells in a fruit fly's brain.
"I stimulated the fly mouth with sugar, and I recorded from this part of the brain," May explains to me. She is comparing the brains of flies that have been fed a steady diet of sugar with those who are raised on a normal diet.
The flies on the high-sugar diet consumed more calories overall than the flies who ate the normal fruit fly food. In other words, a steady diet of sugar makes you eat more than you need. No surprise there. As we've reported before, there's growing scientific evidence that sugar has addictive properties. What May and Dus want to do is find out how a diet high in sugar alters normal control systems in the brain.
Across the hall, Jenna Clem takes a very different approach. She's working with Dus to study the genes in the brain that control eating in fruit flies.
"This is an incredibly complex system," says Clem. She believes that an animal's eating habits and environment change its genes and how they function.
Dus is getting ready to write up some of her early results, and things are looking promising. If she can prove that there are chemical changes in the brain that lead to obesity, it could change the way we tackle the obesity epidemic.
KELLY MCEVERS, HOST:
Many young scientists are having a difficult time getting their careers going, and the reason is often funding - a lack of it. The National Institutes of Health agrees this is a problem, so it established the New Innovator Award. It gives exceptional young scientists a boost. This year's recipients were announced today, and as part of his series Joe's Big Idea, NPR's Joe Palca introduces us to one of the winners.
JOE PALCA, BYLINE: Monica Dus says the way she got into science is fairly typical, but in some ways it's a bit different.
MONICA DUS: I was one of those kids that loved bugs. And I would just go around with my grandpa, and he would catch bugs for me because I'm a little squeamish. And then I just put them in, like, little jars and plastic bags.
And then once I got my microscope, I would take off their legs. But I also really loved Barbies and dolls, and so I would do the same. I would take off the Barbie hair and look on the microscope at that.
PALCA: Monica Dus grew up in Italy and moved to the United States for college and grad school. She was initially interested in fruit fly genetics, but one day there was an incident with her two Bichon Frise dogs. It seems Cupcake and Sprinkles got into a large bag of dog treats, something Dus noticed immediately when she got home.
DUS: And I couldn't believe that these two tiny, 15-pounds animal had huge bellies for three days and that they couldn't stop themself from eating.
PALCA: So she turned her research to using fruit flies to help understand what controls eating. Recently I visited her lab at the University of Michigan. The first thing she did was introduce me to her lab members.
ANOMID VASIDI: My name is Anomid Vasidi.
OLGA GRUSHKO: I'm Olga Grushko (ph).
JENNA CLEM: I'm Jenna Clem.
CALEB VOGT: I'm Caleb Vogt.
CHRISTINA MAY: I'm Christina May.
PALCA: The lab reflects Dus's commitments to helping foreign students and women get a start in research. Dus focusing on how the brain controls what we eat. She's using a variety of scientific disciplines to do that. For example, in one lab, Christina May is working with Dus to study individual cells in a fruit fly's brain.
MAY: I stimulated my fly mouth with sugar, and I recorded from this part of the brain.
PALCA: Across the hall, Jenna Clem takes a very different approach. She's working with Dus to study the genes in the brain that control eating.
CLEM: This is an incredibly complex system, and there is no one factor in other words.
PALCA: So it's not going to have a simply genetic explanation.
CLEM: Right. That's correct. That's correct.
PALCA: The lab has a working hypothesis. Dus believes a diet high in sugar actually changes the brain, so it no longer does a good job of knowing how many calories its owner is taking in. She thinks that might help explain why some people become obese.
DUS: Perhaps it has nothing to do with will and a lot of do with biochemistry.
PALCA: Just like scientists in the last century showed there was a link between smoking and lung cancer, Dus thinks she can find a link between an early exposure to a diet high in sugar and obesity.
DUS: So that we can stop talking about really shaming people about the willpower and focusing on the biochemistry and the public health.
PALCA: If she can do that, she says...
DUS: I will be a very happy person (laughter).
PALCA: She now has five years of funding from the National Institutes of Health to try. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.