In a Free-Living Setting, Obesity Is Associated With Greater Food Intake in Response to a Similar Premeal Glucose Nadir

Abstract

Purpose: Changes in blood glucose levels have been shown to influence eating in healthy individuals; however, less is known about effects of glucose on food intake in individuals who are obese (OB). The goal of this study was to determine the predictive effect of circulating glucose levels on eating in free-living OB and normal weight (NW) individuals.

Methods: Interstitial glucose levels, measured with a continuous glucose monitor (CGM) system, were obtained from 15 OB and 16 NW volunteers (age: 40 ± 14 and 37 ± 12 years; weight: 91 ± 13 and 68 ± 12 kg; hemoglobin A1c: 5.1% ± 0.7% and 5.2% ± 0.4%, respectively). While wearing the CGM, participants filled out a food log (mealtime, hunger rating, and amount of food). Glucose profiles were measured in relation to their meals [macro program (CGM peak and nadir analysis) using Microsoft® Excel].

Results: OB and NW individuals showed comparable CGM glucose levels: mean [OB = 100 ± 8 mg/dL; NW = 99 ± 13 mg/dL; P = nonsignificant (NS)] and SD (OB = 18 ± 5 mg/dL, NW = 18 ± 4 mg/dL; P = NS). Obesity was associated with slower postprandial rate of changing glucose levels (P = 0.04). Preprandial nadir glucose levels predicted hunger and food intake in both groups (P < 0.0001), although hunger was associated with greater food intake in OB individuals than in NW individuals (P = 0.008 for group interaction).

Conclusions: Premeal glucose nadir predicted hunger and food intake in a group of free-living, healthy, nondiabetic NW and OB individuals; however for a similar low glucose level stimulus, hunger-induced food intake was greater in OB than NW individuals.

Figure 1.

Example of the CGM tracing between two subsequent meals in a subject with obesity. The CGM peak and nadir analysis (CPNA; glucose peak, glucose nadir, and glucose decrement) is shown in relation to the meal before the meal of interest. To correct for the lag between serum glucose values and interstitial fluid glucose values measured by the CGM, glucose peak was defined as the highest glucose value at least 15 min after the previous meal, and the nadir was defined as the lowest glucose value up to 10 min after the meal of interest.

Figure 2.

Correlation of premeal glucose nadir, hunger, and food intake. (a) A significantly linear relationship is shown between calorie intake and hunger (P < 0.0001 for each group). The slopes are significantly different (P = 0.008 for group interaction). (b) A significant linear relationship is shown between hunger and the glucose nadir before a meal (slope for OB group: −0.22; P = 0.009 and slope for NW group: −0.14; P = 0.04). However, the slopes did not differ significantly (P = 0.44). The solid black lines represent the data for each OB participant, and the dotted gray lines represent the data for each NW participant. The bold lines represent the average data of the OB (black) and NW (gray) groups.