How many rolls, cookies or baby carrots would you have to eat to feel full. It's probably more than you’d want to admit. It may not even be possible with carrots. But what if you ate that volume of filet mignon?

Hunger and fullness are controlled by hormones that send messages between your gut and your head. And different foods send different messages. Some say eat more and others warn you to slow down. Now a study finds that protein is, indeed, key in generating signals of fullness. The work is in the journal Cell. [Celine Duraffourd et al., "Mu-Opioid Receptors and Dietary Protein Stimulate a Gut-Brain Neural Circuitry Limiting Food Intake"]

Mice that lack receptors to sense that they were eating protein kept chowing down without appearing to feel full. Whereas normal mice would stop eating much sooner while eating a high-protein meal.

The results of the study make it extra impressive that Joey Chestnut wolfed down 68 hot dogs at the Nathan's July 4th hot dog eating contest—with more time he likely would have felt full after a few. But for people eating sensibly, grilled chicken or fish supply satiating protein too.

—Katherine Harmon

[The above text is a transcript of this podcast.]