Every meal you sit down to makes an impression, with foods filed away as something delicious to be sought out again, or to be avoided in disgust if we associate the flavor with gut malaise, colloquially known as a stomach ache.

How this decision is made turns out to be so fundamental to our wellbeing—determining what foods to seek and avoid—that the signals are coordinated within the most primitive parts of our brains, the brain stem or hindbrain. This brain region also helps us decide when we are “full” and should stop eating.

To date, scientists interested in how and why people gain weight and the diseases that can result from overeating and obesity have focused on a part of the brain called the hypothalamus, following discoveries of two intertwined systems that play important roles in controlling energy balance, the leptin and melanocortin systems.

A paper in the journal Nature Metabolism looks outside this brain region and reviews the various brain pathways that meet in the brain stem to control feeding behavior, using a technique that offers an unbiased look at the neurons involved.

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