Sugar Shock: How High-Sugar Diets Impact Taste Sensitivity

October 29, 2023

by Cathe Friedrich

In recent years, there has been growing focus and concern about how much sugar people eat and drink in their daily diet. No wonder! Diets high in sugar are linked with everything from obesity to tooth decay.

An intriguing question around high sugar diets is whether they diminish our ability to taste sweetness, potentially fueling sugar cravings. The concern is that eating large amounts of sugar may desensitize taste receptors. This could then blunt the taste of sweetness itself. If so, people may lose satisfaction from previous sugar levels, driving them to seek higher sugar concentrations. There is also worry this could reduce enjoyment of naturally sweet foods like fruit.

Recently, a group of researchers from the University of Michigan decided to dig deeper into this issue. They designed a study to analyze how habitual high sugar intake impacts sensitivity to sweet taste. The team wanted fresh data to shed light on whether dampened taste perception does in fact contribute to sugar cravings.

According to the results of a study, a high-sugar diet can indeed desensitize the tongue to sweet tastes and reduce responsiveness to dietary sugar by up to 50%. Let’s look at the details of this study, exploring its implications and potential relevance to human health.

What a Study Showed about Sugar and Taste Sensitivity

To explore the impact of a high-sugar diet on taste sensitivity, researchers at the University of Michigan designed an experiment. They divided rats into two categories. Both groups ate a standard diet, but one group got sweetened drinking water. This approach allowed the researchers to isolate the effect of the high sugar content, as the only difference between the two groups was the sugar in their diet.

After keeping the rats on their assigned diets for 4 weeks, the research team assessed responses in the chorda tympani nerve. This nerve carries taste signals from the front of the tongue to the brain. The researchers monitored the nerve’s electrical activity when the rats consumed or tasted substances.

The outcomes of this study were not only remarkable but also unequivocal. While both sets of rats had similar reactions to salty, sour, bitter, and umami tastes, as well as to cold and tactile sensations, when the researchers offered them a sugar water solution, their responses differed. Rats on the high-sugar diet responded less to sweetness, with a reduction in sensitivity to sugar by up to 50%.

This reduction in sensitivity to sweetness was not a subtle or gradual change; it was both rapid and substantial. In fact, Monica Dus, the lead author of the study, emphasized the strength of this effect, stating, “This is not a subtle effect. It is really strong, and it only took four weeks.” This finding underscores the potential impact of high-sugar diets on our perception of sweetness.

The Lack of Sensitivity to Sugar Is Reversible

One intriguing aspect of this study is the reversibility of the “sugar” effect. After the rats went back to their regular diet and washed it down with water without sugar, their sensitivity to sweetness returned within four weeks. So, at least in this study, the desensitization that happens with a high-sugar diet is not permanent.

Instead, it suggests that taste buds have plasticity, or the ability to change their response with time and what they’re exposed to. This raises intriguing questions about how dietary changes could impact our preferences and metabolic health.

When they dug deeper for a full explanation of this phenomenon, they found no differences in the taste buds or nerves of the rats that consumed the sugar water. Rather, they had fewer sweetness-detecting cells compared to the rats that ate a diet that didn’t contain sugar. By being exposed to so much sugar, the number of cells that detected sweetness went down, making it harder for them to detect a sweet taste.

Does the Same Hold True for Humans?

This study offers persuasive evidence regarding the influence of high-sugar diets on the sensitivity of taste receptors in rats. Could this mechanism be applicable to humans too? Given the noteworthy parallels in our taste systems with those of rats, this research represents the most compelling evidence to date that high-sugar diets could potentially modify our sensory perception. The repercussions of such a discovery may extend significantly to our dietary preferences and metabolic processes.

There are still unanswered questions. How does a high-sugar diet affect dopamine, the reward hormone? According to some studies, sugar triggers a release of dopamine that is rewarding. To keep getting that good feeling, we want more sugar, like how a gambler keeps playing to win. This is why some sources say that sugar is addictive.

The results from these rat studies present fascinating implications for understanding sugar cravings in humans too. The parallels in biology suggest similar mechanisms could be at play. However, since this research was on animals, important questions remain. Scientists still need to determine if diminished taste perception occurs in people and drives increased sugar consumption.

Further studies are required to know whether this phenomenon directly translates to consequences for human sugar cravings and diet. While these initial findings are promising, more work is required to grasp their relevance to sweet taste perception and cravings in human nutrition and health.

What Might This Mean for Your Own Diet?

When you munch on sugary foods or drink sugar-sweetened soft drinks, it may, over time, reduce your taste sensitivity to sweetness. Therefore, you crave more sugar to get the same satisfaction. Have you ever stopped eating sugar for a while and then tried a sweet dessert?

If so, you may have noticed that it tasted too sweet for your taste buds. That’s because your taste buds recovered their sensitivity to sweetness when you abstained from sugar, and you’re able to detect even small amounts of sugar in food. Whereas you might have eaten a whole dessert before, you’re now satisfied with a single bite because your taste buds are on high alert for sweetness.

Conclusion

This intriguing study shows how a diet rich in sugar can potentially alter our perception of sweetness and influence the way we respond to sweet stuff. Although the study involved non-human subjects, it provokes thought-provoking inquiries into its potential implications for humans. Such findings could wield a substantial influence over our dietary preferences and, consequently, our overall well-being.

Until we know more, limit the amount of sugar in your diet, so you don’t desensitize your taste buds. When your taste buds are less responsive to sugar, you can’t appreciate the natural sweetness of whole fruits and vegetables and crave more ultra-processed foods with added sugar.

References:

https://newatlas.com/author/michael-irving. High-sugar diet desensitizes the tongue to sweet tastes, says rat study. New Atlas. Published October 21, 2022. Accessed September 7, 2023. https://newatlas.com/biology/high-sugar-diet-desensitizes-sweet-taste/#:~:text=Do%20people%20eating%20lots%20of,in%20responsiveness%20to%20sweet%20flavors.
‌ Sung H, Vesela IV, Driks H, et al. High-sucrose diet exposure is associated with selective and reversible alterations in the rat peripheral taste system. Current Biology. 2022;32(19):4103-4113.e4. doi:https://doi.org/10.1016/j.cub.2022.07.063.
“Why Taste Buds Change: 7 Causes and Treatments – Healthline.” 22 Jun. 2020, https://www.healthline.com/health/dental-and-oral-health/taste-buds-change.