Surprise, Not Disgust, Barrier to Eating Insects, Study Shows

A Portuguese brain-and-heart study found that surprise, not disgust, may be the real barrier to eating insects.

In many Western countries, the idea of eating a bug triggers a quick “no,” and disgust and fear are the reasons researchers usually point to. A new study from Portugal, published in the Journal of Neuroscience, Psychology, and Economics, complicates that picture. What people say about insect food and how their bodies react when they eat it turned out to be two very different things.

Researchers strapped participants into brain-reading headsets and heart monitors, handed them protein bars made with insects, and recorded what happened. Their bodies took notice. Brain activity tied to attention picked up, heart rates climbed during the first bites, and afterward, when asked which bar they liked best, most picked the insect one. Surprise, not revulsion, was the emotion that surfaced most often.

That distinction matters for a food source many scientists consider a serious answer to a growing problem. With the global population expected to pass nine billion by 2050, researchers have been hunting for proteins that ask less of the planet than cattle and pigs do. Insects fit the brief: research links them to fewer greenhouse gases and far less land and water than conventional livestock, along with dense nutrition. Getting people to take the first bite has been the sticking point.

How the Insect Protein Study Worked

Conducted in Portugal, the study recruited adults between 18 and 55 who had never eaten insect-based food. After researchers filtered out recordings spoiled by talking or chewing at the wrong moment, 38 participants remained. That group skewed young and educated, a limit the authors are upfront about.

Before anyone ate, participants answered a survey about insect food. Almost half already knew such products were sold in Portuguese stores, and 67% said they were curious to try them. Yet only 8% had ever spotted one on a shelf, and just 3% could name an insect legally sold as food, with the grasshopper the most recognized. Asked how they felt about the idea of eating insects, participants named their emotions in this order: surprise, fear, happiness, disgust. Researchers found a statistically meaningful link between those emotions and whether someone pictured eating insects down the road. As the authors put it, “when people are informed about it, they are more likely to accept it.”

Then came the tasting. Participants were split into four groups along two lines: whether they were told the truth about what they were eating, and which bar came first. Both bars shared an apple-and-cinnamon flavor, but one was made with insect protein and the other was an ordinary cereal bar. Some people were told they were eating a cereal bar when it was actually the insect one. Throughout, an EEG headset tracked electrical activity at eight points on the scalp while a separate device logged each heartbeat, before, during, and after every bite.

What Happened When People Ate the Insect Protein Bar

Eating the insect bar lit up patterns of heightened attention and stepped-up visual processing, the kind of brain activity that goes with being alert. Heart rate backed that up: in several groups, it ran measurably higher during the insect bar than in the calm moments before or after. None of this depended on knowing. People who believed they were biting into a plain cereal bar showed broadly similar responses, their bodies registering something their minds had not been told.

Preference followed the same direction. Across most groups, participants picked the insect bar as their favorite. The groups were small, only nine or ten people each, but the pattern held: in one, 89% chose the insect bar, and in another, 70% of people who had been told they were eating a cereal bar still named the insect version as the one they liked best.

Why Disgust Isn’t the Real Barrier

Here is where the results push back on a long-standing belief. For years, disgust has been cast as the wall between insects and Western dinner plates. This study points elsewhere. Disgust did register, but the authors read the heavy dose of surprise as the real signal: unfamiliarity, not deep revulsion, is what keeps people at arm’s length. The bars, after all, did not look like bugs. They looked and tasted like apple and cinnamon.

Openness ran higher than the researchers expected, with about 71% of participants saying they could see themselves eating insect food in the future. Based on that, the authors sketch a two-step plan. First, trusted public institutions build basic knowledge about safety, nutrition, and environmental benefits. Then companies step in with targeted marketing and, above all, free samples and in-store tastings. Letting people taste the food directly, they argue, does more to melt hesitation than any pitch about novelty.

Pairing brain and heart monitoring this way had not been tried before on insect food, and the authors say the combination revealed more than surveys alone could. If insect protein is going to reach more plates across Europe, the first move may not be arguing anyone out of disgust. It may be handing them a bar and letting their bodies answer before their opinions can.

Disclaimer: This article summarizes a peer-reviewed study for a general audience. It is not scientific, dietary, or health advice. The research involved 38 participants in Portugal, and findings from a sample this small may not apply to other populations.