Being hungry activates a small group of neurons that are involved with negative feelings. Research has found that having a meal stops this brain activity, bringing on a sense of happiness.

Eating, dining and feasting are some of the most rewarding human experiences often bringing about happiness and feelings of comfort. These feelings of happiness and reward after eating are rooted in the human brain and learning creates some of the pathways.

With each meal, neural pathway circuits that link food with good times and experiences are reinforced. Another explanation for the enjoyment associated with food and eating is that when we eat we suppress negative pathways in the brain.

A team of scientists in the US have been following the activities of small subsets of neurons in the brains that produce AGRP (agouti-related protein). Their research is performed on mice.

These neurons fire when a mouse (or human) is hungry. Scientists were able to switch on and off these neurons using highly selective chemicals implanted in the brains of the mice.

When activated, the AGRP neurons made the mice unhappy with them retreating to the corner and not engaging socially. The opposite was true when the AGRP neurons were switched off. In this case the mice went out and explored new places, including unfamiliar objects and generally socialised well with other mice.

Implications

This experimental work highlights that being hungry triggers the AGRP neurons and causes negative feelings. It’s the root cause of the negative moods associated with being hungry.

Eating switches these neurons off, alleviating these moods and increasing the feeling of happiness and reward. This reiterated how difficult it may be to take on the simple strategy of eating less to lose weight.

A more holistic approach to weight loss may need to be taken including eating nutritious foods that are known to promote satiety and getting plenty of exercise.

Last Reviewed: 25/08/2019

© Norman Swan Medical Communications.



References

Betley JN et al. Neurons for hunger and thirst transmit a negative-valence teaching signal. Nature 2016;521:180-185.