Int J Obes (Lond)Mechanisms & ScienceRCTDecember 22, 2025

Impact of ultra-processed foods on short-term appetite regulation: Does body mass index make a difference?

Çelik MN, Ulug E

View on PubMed DOI: 10.1038/s41366-025-01961-9

Key Finding

Ultra-processed breakfast foods triggered 67% higher insulin levels and increased hunger sensations compared to regular processed foods, regardless of whether people were normal weight or overweight.

What This Study Found

Think of your body's appetite control system like a complex orchestra - hormones like insulin, GLP-1, and GIP are the different instruments that need to play in harmony to keep you satisfied after eating. This study compared how two different 'conductors' (processed vs ultra-processed breakfasts) affected this orchestra in 28 people, split between normal weight (18 people) and higher weight (10 people) groups. The researchers served as metabolic detectives, taking blood samples every 30 minutes for 2 hours after breakfast to track exactly how these appetite hormones responded. What they discovered was surprising: ultra-processed breakfasts made the insulin 'instrument' play much louder (higher levels throughout the 2-hour period), while people also reported feeling hungrier on a visual scale - like their appetite thermostat was broken. This happened regardless of whether someone was slim or carrying extra weight, suggesting that the degree of food processing itself - not your current weight status - is what throws off your body's natural appetite regulation system.

Statistics Decoded

The key finding comes from 'total area under the curve' (tAUC) measurements - imagine plotting hormone levels on a graph over 2 hours, then calculating the total area under that curve. For hunger sensations, the p-value was 0.009 (like flipping heads 25+ times in a row - this wasn't just chance). For insulin, p = 0.016 (still very unlikely to be random, like rolling the same number on a die 15 times). The study was small with only 28 people, and notably uneven groups (18 normal weight vs 10 higher weight), which limits how broadly we can apply these findings. All other measurements showed p > 0.05, meaning those differences could easily have been due to chance.

Why This Matters

This suggests that ultra-processed foods might literally hijack your body's hunger signals, making you feel hungrier and triggering higher insulin spikes even when you've eaten the same amount of calories - a potential mechanism explaining why ultra-processed foods contribute to overeating and weight gain regardless of your starting weight.

Original Abstract

Limited studies have examined the effects of meals containing processed foods or ultra-processed foods (UPF) on appetite regulation and results were inconsistent and difficult to generalize. Therefore, the study aimed to evaluate the potential efficacy of two different breakfasts containing processed foods or UPF on postprandial appetite regulation in adults with different body mass index (BMI). Twenty-eight participants (eighteen with normal BMI (BMI: 18.50-24.99 kg/m2), ten with high BMI (BMI > 25.0 kg/m2) were included in the study. General demographic information form, food consumption records, and Screening Questionnaire of Highly Processed Food Consumption (sQ-HPF) were applied and anthropometric measurements (body weight, height, waist circumference, waist/hip ratio and waist/height ratio) were taken. Participants made two visits, 2 weeks apart, and were offered two different breakfasts: Processed Breakfast and UPF Breakfast. Blood samples were collected before starting the meal (0 min) and 30, 60, 90, and 120 min after taking the first bite, and serum glucose, insulin, amylin, GLP-1, and GIP levels were analyzed using ELISA/colorimetric methods. Also, participants were administrated a visual analogue scale (VAS) to subjectively assess appetite regulation at the same times. Daily energy, macro and micronutrients consumption were similar across BMI groups for both breakfast in prior the experiment and throughout the rest of the experimental day (p > 0.05). The total area under the curve (tAUC) for hunger sensation and insulin were higher after the UPF Breakfast compared to the Processed Breakfast (p = 0.009, p = 0.016, respectively). Other data were no different both between breakfast types and different BMI groups. Overall, while short-term appetite hormone responses to UPF Breakfast and Processed Breakfasts were similar, higher insulin levels and subjective feelings of hunger, following UPF Breakfast independent of BMI status. These findings suggest that the degree of food processing, rather than BMI, may influence specific aspects of postprandial appetite regulation.