Fruit Fly Eggs Drive Sugar Cravings

Zita Santos & Carlos Ribeiro

Just like growing children need a hearty diet for their development, so do growing cells. But unlike children, cells can reprogram their metabolism to burn more sugar and grow faster. These small changes deliver a big impact: they alter what an organism wants to eat.

Metabolic reprogramming was first noticed in the rapid growth of tumor cells, but scientists have now spotted it during normal development. As eggs in female fruit flies mature and grow from germline stem cells (shown here outlined in green), they switch their metabolism to require more sugar. Burning more sugar enables the fruit flies to produce more eggs.

In a recent study published in Nature Metabolism, researchers genetically stopped sugar metabolism in the germline cells of female fruit flies and watched their feeding behavior. After being deprived of carbohydrates, flies without a functioning germline did not eat any sugar, even though their bodies needed it. This hints that immature eggs inform the brain of their need for carbohydrates and drive sugar appetite. The research team at the Champalimaud Centre for the Unknown in Portugal identified how eggs relay this information: a fullness peptide called Fit. The Fit peptide tunes in to the nutritional needs of the developing eggs and suppresses or encourages sugar appetite accordingly. Scientists are not sure how exactly Fit conveys this information, but future studies could answer questions about how cellular needs influence an organism’s behavior.

About the Author

Calli McMurray

Calli McMurray is the Media & Science Writing Associate at SfN. She graduated from the University of Texas at Austin in 2019 with a Bachelor of Science in Neuroscience.