679: Overnight fasting and its impact on experimentally induced central pain plasticity in humans

Topic: Experimental (Non-clinical) Human Studies
Subtopic: Non -specific to any diagnosis, Non-pharmacological treatments, Pain mechanisms (e.g. descending inhibitory control, placebo, inflammation)

Background and Aims: Animal research suggests fasting attenuates pain arising from sensitization of nociceptive pathways [1], but evidence in humans is scarce. Using established experimental models of nociceptive sensitization, we examined whether overnight fasting reduces secondary mechanical hypersensitivity in healthy volunteers and whether effects depend on fasting duration or sensitization model.

Methods: Across two experiments, we varied fasting duration and sensitization procedures. Experiment 1 compared a 12-hour fast condition with re-feeding one (N=33, within design, 1 week apart); Experiment 2 (N=52, between design) compared a group after a 16-hour fast with a group eating their normal breakfast. Mechanical hypersensitivity was induced using mid-frequency electrical stimulation (MFS, Experiment 1) or high-frequency stimulation (HFS, Experiment 2) of the skin. We assessed pinprick intensity, unpleasantness, hypersensitive area size, and stimulation pain ratings.

Results: A 12-hour fast did not alter experimentally induced hypersensitivity, nor acute pain to the electrical stimulation (MFS, Experiment 1). A 16-hour fast showed a trend toward reduced mechanical hypersensitivity (p=0.049 partial eta square= 0.069), although effects were not robust in follow-up analyses. Also in experiment 2, fasting did not influence baseline pinprick sensitivity or stimulation pain ratings.

Conclusions: Overnight fasting showed limited effects on experimentally induced central pain plasticity under the conditions of Experiment 1. However, Experiment 2 suggests that longer fasting durations and less intense sensitization paradigms warrant further investigation, particularly in relation to dietary patterns. More tailored dietary approaches and improved control of metabolic changes may provide new insights into how fasting influences the development of mechanical hypersensitivity in humans.

References: [1] Alhadeff, A. L., Z. Su, E. Hernandez, M. L. Klima, S. Z. Phillips, R. A. Holland, C. Guo, A. W. Hantman, B. C. De Jonghe and J. N. Betley (2018). "A Neural Circuit for the Suppression of Pain by a Competing Need State." Cell 173(1): 140-152 e115.

Presenting Author: Diana M.Torta
Submitting Author: Diana Torta

Senior Author: Emanuel van den Broeke

IASP 2026 Global Year theme of Neuropathic Pain: No

• Diana M.Torta: PhD - Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium; Pain Focus Group, Leuven Brain Institute KU Leuven
• Anouk Teugels - Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
• Tabea Eimer - Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
• José Balbuena-Sanchez - Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
• Lukas Van Oudenhove: PhD - Laboratory for Brain-Gut Axis Studies (LaBGAS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven
• Emanuel van den Broeke: PhD - Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium; Pain Focus Group, Leuven Brain Institute KU Leuven