New Study Finds Why Food Tastes Better When You're Hungry
If you've tried intermittent fasting, had to skip a meal on a busy day, or been ravenous after a tough workout, you don't need me to tell you that food tastes better when you're hungry. Honestly, there's nothing better than sitting down to a meal when your stomach is growling, savoring every last taste, even if it's not your favorite food.
But have you ever wondered why everything tastes good when you're hungry? New research from the National Institute for Physiological Sciences in Japan shows that fasting actually makes food taste sweeter and that two specific neural circuits are to blame for this phenomenon.
Why food tastes better when you're hungry.
Published in the journal Nature Communications, the study showed that fasting mice had a greater preference for sweetness and a decreased sensitivity to aversive tastes, which typically come from sour or bitter foods.
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."
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.
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