Have you ever wondered why food tastes so good when you are hungry? People on diets should be forgiven for moaning that chocolate tastes better when you’re hungry. Just missing breakfast makes you more sensitive to sweet and salty tastes, according to research to be published next week in BMC Neuroscience.
Hunger could increase your ability to taste, by increasing the sensitivity of the taste receptors on your tongue, or by changing the way you perceive the same taste stimuli, the author suggests.
So how does it work?
The researchers found that a specific type of brain cell—called an Agouti-related peptide (AgRP)-expressing neuron—is responsible for these hunger-induced changes in taste preferences. As lead author on the study Ou Fu explained, “AgRP-expressing neurons are found in the hypothalamus, which is a brain region that plays a vital role in appetite regulation.” The team activated those neurons on purpose and observed whether or not they influenced the perception of taste after a fast.
The results showed that once the AgRP neurons were activated, glutamate neurons in the hypothalamus caused changes in taste in two different pathways. First, glutamate neurons that project into the lateral septum (a part of the brain associated with reward signaling) increased the preference for sweet tastes; and second, the glutamate neurons projecting into the lateral habenula (a part of the brain typically activated by unpleasant events) worked to decrease the mice’s sensitivity to bitter tastes.
Could altering taste preferences help fight disease?
Identifying these specific pathways means that in the future, we could develop a way to control taste preferences in other ways, especially in ways that help us fend off lifestyle- and diet-related illnesses. As another author on the study, Yasuhiko Minokoshi, explained, “The next steps will be to investigate whether these hypothalamic neuronal pathways are altered in pathophysiological conditions such as diabetes and obesity.”
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And considering the fact that 100 million Americans are currently living with diabetes or prediabetes and almost 40% of Americans are obese, this could have massive health implications. We’re a long way off from actually doing this, but as Minokoshi explains, “…we already know that people with obesity have a strong preference for sweetness; this might be associated with a change in the activity of the glutamate neurons projecting to the lateral septum.”
For now, it’s interesting to know why, exactly, our food tastes so good when we’re hungry. The findings could even explain why so many intermittent fasters report that the practice has helped them make healthier choices and appreciate their food more. If you want to test it out for yourself, here’s our beginners’ guide to intermittent fasting.