This story is one in a series marking International Women and Girls in Science Day. Join us as we celebrate some laboratory leaders taking research to new heights.

We’ve all had food cravings, whether it’s a hankering for a sugary snack or a savory slice of pizza. But have you ever thought about what motivates those cravings? Qili Liu, PhD, hopes to unlock insights that could help address the obesity epidemic.

An assistant professor of anatomy at UC San Francisco, Liu and her lab study the biological basis of appetites and how those appetites ensure a balanced diet.

How do you research cravings?

I study protein-specific appetites in flies. Flies eat very diverse types of nutrients. When female flies are pregnant, for instance, their appetite for protein increases drastically, and they seek out protein-rich food, such as the yeast from decaying plants and fruit.

How did you figure that out?

I started thinking about protein cravings because I was pregnant. I wanted to eat eggs, even though I really don’t like eggs. I realized there was much more to be researched about what drives this kind of an appetite.

What path did you take to this research?

I majored in biology as an undergraduate in China. I studied the reproductive strategies of a wild plant species, learning how it adapts to and takes advantage of its environment. I earned my doctorate, also in China, studying stem cells in Arabidopsis, a model plant.

For my postdoc, at Johns Hopkins, I studied biological processes shared by plants and animals. I focused on the circadian rhythm and developed genetic tools to dissect neurons that regulate sleep. I decided to use those tools to study hunger for particular nutrients.

How do flies help you better understand humans?

Most animals naturally seem able to eat a balanced diet, but we don’t know why. Knowing more about this could shine a light on why it seems so challenging for humans to eat a balanced diet.

The circuitry in flies and humans is very different. What we are learning about flies is not immediately translatable to humans, but the molecular pathways are similar. We know now, for example, that there is nerve circuitry that can not only lead animals to eat protein but also stop them from seeking sugar. This suggests a competition between types of hunger. Knowing this might help us understand how to ensure one kind of hunger doesn’t dominate over others in humans and lead to health issues such as obesity.

And this could help address obesity in humans?

Growing evidence suggests lack of protein consumption is a significant but ignored contributor to the obesity epidemic. Better understanding the drivers of this may reveal novel therapeutic targets for treating obesity in humans.

Margaux Pinney stands and smiles against an abstract backdrop of research imagery


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