Effects of Inulin Propionate Ester Incorporated into Palatable Food Products on Appetite and Resting Energy Expenditure: A Randomised Crossover Study

This was a randomized, double-blind, crossover study in healthy overweight or obese adults aged 18 to 65 years with BMI 25 to 40, conducted in London, United Kingdom. Twenty-three participants were randomized and 21 completed all four study visits; ad libitum food intake was analyzed in 19 participants.

In a randomized crossover regimen, participants consumed palatable food products (one bread roll and one fruit smoothie daily) containing inulin-propionate ester (IPE) or inulin as a positive control. Each supplemented food pair provided 10 g/day total supplement dose for 6 days, with a seventh supervised consumption on the post-supplementation visit; the supplement was delivered orally within food rather than as a standalone product.

Adding inulin-propionate ester to bread rolls and smoothies was well tolerated and did not change palatability, while reducing ad libitum energy intake in the crossover test. The overall treatment effect for intake was significant (p = 0.012); post hoc comparisons showed trends favoring IPE versus control (p = 0.056) and versus inulin (p = 0.059), whereas inulin did not differ from control (p = 0.75). The appetite effect was not explained by peripheral PYY or GLP-1 changes, and the higher resting energy expenditure seen with IPE was not robust after adjustment for fat-free mass (p = 0.22-0.37). Inulin produced more breath hydrogen and more gastrointestinal side effects than control, with no significant side-effect difference between IPE and inulin.

The trial was small, with only 21 completers and 19 participants contributing to the ad libitum intake analysis. Supplementation was short term, and several secondary findings did not remain significant after adjustment for fat-free mass, limiting mechanistic inference. Generalizability is restricted to healthy overweight or obese adults in a crossover feeding setting.