New research finds that ultra-processed foods taste no better than less processed foods

Press release issued: 27 November 2023

New research that compared the taste perception of less processed foods with ultra-processed foods (UPFs), found participants viewed UPFs no more pleasant tasting than less processed foods. The University of Bristol-led findings, published in the journal Appetite today [27 November], supports the theory that humans are programmed to learn to like foods with more equal amounts of carbohydrate and fat. Carbohydrate (including sugars) and fat provide most of the calories in human diets.

The study, led by Bristol's Nutrition and Behaviour Group, wanted to test the common but largely untested assumptions that food energy density (calories per gram), level of processing, and carbohydrate-to-fat ratio are key factors influencing food liking and desirability.

In the experiment, involving 224 adult volunteers, participants were presented with colour images of between 24 and 32 familiar foods, varying in energy density, level of processing (including UPFs), and carbohydrate-to-fat ratio. There were 52 different foods in total, including avocado, grapes, cashew nuts, king prawns, olives, blueberry muffin, crispbread, pepperoni sausage, and ice cream.

Participants were then asked to rate the foods for taste pleasantness (liking), desire to eat, sweetness, and saltiness while imagining tasting them. The validity of this method was confirmed by, for example, finding a strong relationship between sweetness ratings and food sugar content.

Results from the study showed that, on average, UPFs were no more liked or desired than processed or unprocessed foods. However, foods that combined more equal amounts (in calories) of carbohydrate and fat, were more liked and desired than foods containing the same number of calories mostly as carbohydrate, or mostly as fat. This is known, from previous research, as the 'combo' effect.

Further results revealed that foods with higher amounts of dietary fibre were less liked and desired, and foods tasting more intense (mainly related to the level of sweetness and saltiness), were more liked and desired.

Read the full University of Bristol news story

‘Evidence that carbohydrate-to-fat ratio and taste, but not energy density or NOVA level of processing, are determinants of food liking and food reward' by Peter J. Rogers et al. in Appetite