The findings, led by the University of Bristol, revisit the long-held belief that humans are insensitive to the energy content of the foods they consume and are therefore likely to eat the same amount of food (by weight) as whether or not it is energy. -rich or poor in energy.

The study, published today in The American Journal of Clinical Nutrition, is particularly important because it challenges the common belief among researchers that people are likely to overeat energy-dense foods.

This idea stems from previous studies that manipulated the energy content of foods or meals to create low and high energy versions. In these studies, people were not told whether they ate a low- or high-energy version, and the results showed that they tended to eat meals of the same weight, resulting in higher caloric intake with the high energy version.

“For years, we believed that humans were eating energy-dense meals unnecessarily. Remarkably, this study indicates a degree of nutritional intelligence by which humans manage to adjust the amount they consume of energy-dense options. “said lead author Annika Flynn, a PhD student. Nutrition and behavior researcher at the University of Bristol.

Rather than artificially manipulating the calories of a single food, this study looked at data from a trial using normal daily meals with different energy densities, such as a chicken salad sandwich with fig biscuits or porridge with blueberries and almonds. The trial involved 20 healthy adults who lived temporarily in a hospital ward where they were served a variety of meals for four weeks.

The team of international researchers, including leading food and metabolism experts from the National Institutes of Health (NIH) in the United States, calculated calories, grams and energy density (calories per gram) for each meal consumed by each participant. The results demonstrated that meal calorie intake increased with energy density in low-energy meals, as was also found in previous observations with artificially manipulated foods. However, surprisingly, with greater energy density, a turning point has been observed where people begin to respond to calorie increases by reducing the size of the meals they consume. This suggests a previously unrecognized sensitivity to the energy content of the meals people ate.

As this finding was based on data from a small, highly controlled trial, the researchers then investigated whether this pattern persisted when participants lived freely, choosing their own meals. Using data from the UK National Food and Nutrition Survey, the researchers again found that calorie intake from meals increased with energy density in energy-poor meals and then decreased in high-energy meals. energy. Importantly, for this reversal pattern to occur, participants would have had to consume smaller meals, by weight, among the more energy-dense meals.

Annika said: “For example, people ate smaller portions of a creamy cheese pasta dish, which is an energy-dense meal, than a salad with lots of different vegetables which is relatively low in energy.”

This research sheds new light on human eating behavior, particularly an apparent subtle sensitivity to calories in energy-dense meals.

Co-author Jeff Brunstrom, professor of experimental psychology, said: “This research lends more weight to the idea that humans are not passive eaters after all, but show the discerning ability to moderate the amount of an energy-dense meal they consume.

“This work is particularly exciting because it reveals a hidden complexity of how humans interact with modern energy-dense foods, something we call ‘nutritional intelligence’. What this tells us is that we we don’t seem to passively overconsume these foods and so why they’re associated with obesity is more nuanced than previously thought.For now, this at least offers a new perspective on a long-standing problem and opens the door to a series of important new questions and avenues for future research.”

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