DOI: 10.17028/rd.lboro.31150822.v1
title: The association between glucose dynamics and energy intake in young, healthy women

description: Background:Glucose has been implicated in the control of appetite and food intake. This study investigated whether glycaemic patterns relate to energy intake and whether appetite-related hormones mediate this relationship.<br>Methods:Thirty healthy young women (age: 25 ± 4 years; BMI: 21.4 ± 2.0 kg/m2) arrived at the laboratory at 8:00 AM after an overnight fast. Upon arrival, participants completed a 30-minute resting period, during which the cannula was inserted, and all fasted glucose measurements were collected. Glucose was measured every 5 minutes using FreeStyle Libre 2™ continuous glucose monitors (CGM), and one venous plasma glucose sample was obtained immediately after cannula insertion. Following the 30-minute fasting measurement period, participants consumed a fixed breakfast and then remained in the laboratory for an additional 240 minutes. Glucose was monitored via CGM every 5 minutes and via venous plasma (VPG) every 15 minutes after breakfast. Energy intake was assessed at 240 minutes using an ad-libitum homogeneous pasta meal. Subjective appetite ratings were collected fasted and every 15 minutes after breakfast. Appetite-related hormones, including insulin, acylated ghrelin (AG), total glucagon-like peptide-1 (GLP-1) and oxyntomodulin (OXM) were measured in the fasted state, immediately after breakfast (t = 0 minute), and subsequently at 30-minute intervals after breakfast until t =240 minutes. Menstrual cycle phase was recorded and included as a covariate in all analyses. Associations between glycaemic variables and satiety or energy intake were examined using generalised linear models with a gamma distribution and log link function, adjusting for BMI and menstrual cycle phase. Bootstrap-based causal mediation analyses were conducted to evaluate whether appetite-related hormones mediated any significant associations between glycaemic responses and satiety or energy intake.<br>Results:CGM-derived glucose nadir (lowest concentration) and dip (deviation of nadir from baseline as a percentage) were significantly associated with subsequent energy intake. A higher glucose nadir was associated with lower energy intake (β = 0.17; p &lt; 0.001), whereas a greater glucose dip was associated with higher energy intake (β = 0.007; p &lt; 0.001). When standardised, a one standard deviation (SD) increases in glucose nadir corresponded to an approximately 13% reduction in energy intake, while a one-SD increase in glucose dip corresponded to an approximately 16% increase in energy intake. Glucose nadir (CGM: β = 0.227, p = 0.003; VPG: β = 0.256, p &lt; 0.001) and dip (CGM: β = 0.008, p &lt; 0.001; VPG: β = 0.012, p &lt; 0.001) derived from both CGM and VPG were also significantly associated with overall satiety measured immediately before the ad libitum lunch. A one-SD increase in glucose nadir was associated with higher satiety (CGM: 23% increase; VPG: 19% increase), whereas a one-SD increase in glucose dip was associated with lower satiety (CGM: 15% reduction; VPG: 19% reduction). Causal mediation analyses provided no evidence that insulin, acylated ghrelin, total GLP-1, or oxyntomodulin mediated these associations (p ≥ 0.10).<br>Conclusions:Glucose dynamics including nadir and dip may influence satiety and subsequent energy intake. These data support for a role of glucose in models of appetite regulation.© the authors