Differences in maintenance of mean blood glucose (BG) and their association with response to "recognizing hunger"

Abstract

Background: Meals begin and end subjectively. We trained healthy subjects to recognize initial hunger as a preprandial target for meal consumption, and to create a "recognizing hunger" or initial hunger meal pattern.

Objective: Training subjects to "recognize hunger" lowers blood glucose (BG) and improves energy balance, and lowers metabolic risks and bodyweight. A minority may have low BG and low metabolic risks at recruitment, but the others may recover this favorable condition by training.

Methods: In a 7-day food diary, subjects reported their preprandial BG measurements; BG and energy availability by blood were assessed at the lowest BG during the day, and diary-mean BG thus characterized the individual meal pattern (daily energy intake). We analyzed the same diaries of a recent paper on a global, randomized comparison of subjects trained in "recognizing hunger" with control subjects. This time, we checked whether subjects who had maintained low BG (LBG subgroup) at recruitment were able to decrease mean BG and metabolic risk factors during "hunger recognition" like those who presented high BG (HBG subgroup).

Results: At recruitment, the BG means of 120 investigated subjects were within mean confidence limits of ± 3.84 mg/dL, and we could stratify subjects in ten small strata of which each significantly differed by mean BG. Mean BG was stable in each control subject over five months; the mean absolute change being 6.0 ± 4.6 mg/dL. Only three out of 34 trained subjects who had lower mean BG than 81.8 mg/dL significantly decreased mean BG, whereas 41 out of 55 subjects whose mean BG was greater than 81.8 mg/dL significantly decreased mean BG after training (P < 0.0001). At recruitment, the LBG subgroup showed significantly lower insulin, lower BG area under curve (AUC) in the oral glucose tolerance test (GTT), and lower HbA1c than the HBG group. After training, only HBG subjects, compared with HBG controls, significantly decreased preprandial BG from 91.6 ± 7.7 mg/dL to 81.0 ± 7.7 mg/dL, in association with a decrease of HbA1c from 4.81% ± 0.44% to 4.56% ± 0.47%, of GTT insulin AUC from 244 ± 138 mU/L to 164 ± 92 mU/L, and of energy intake from 1872 ± 655 kcal to 1251 ± 470 kcal (P < 0.001), with an increase of indices of insulin sensitivity from 5.9 ± 3.3 to 9.8 ± 5.6 and of beta cell function from 1.0 ± 0.7 to 1.4 ± 1.1 (P < 0.05). LBG subjects only decreased weekly-diary BG standard deviation in comparison with controls.

Conclusion: At recruitment, the 120 subjects maintained mean BG at one personal level of ten possibilities, and 34 subjects were below 81.8 mg/dL (LBG) and 55 were over (HBG). The 55 HBG subjects showed higher mean insulin resistance, HbA1c, other cardiovascular risk factors, and increased bodyweight compared with the 34 LBG subjects. A total of 41 out of the 55 HBG subjects regressed to LBG with training.

Keywords: energy balance; energy intake; homeostasis; preventive medicine; subjective sensations.

Figure 1

Consort flow chart and study design. Notes: Randomized and controlled 5-month clinical investigation to study mean blood glucose at recruitment and it’s association with response to “recognizing hunger”. Abbreviations: GTT, glucose tolerance test; HBG, high blood glucose; IHMP, initial hunger meal pattern (recognizing hunger); LBG, low blood glucose.

Figure 2

Increasing sequence of mean BG of all 120 trained and control subjects divided into ten strata (columns) at recruitment. Notes: Strata consist of subjects with no significant difference in mean BG inside the stratum. Moreover, each stratum excludes subsequent subjects whose mean BG is significantly higher than that of the first subject in the stratum. Column height shows the first component. Mean BG is reported in sequentially increasing order at recruitment, not in linear correlation with segment length on the x-axis scale. Abbreviation: BG, blood glucose.

Figure 3

Difference after training versus value in mean blood glucose for each trained subject at recruitment. Notes: Column height shows 5-month post- less pre-mean blood glucose difference from 7-day diary in each trained subject. Significant increases in blue, significant decreases in red, and no significant changes in black. Mean blood glucose reported in sequentially increasing order at recruitment, not in linear correlation, with segment length on the x-axis scale. The dashed division indicates the most significant division between subjects who showed no mean blood glucose decrease after training (LBG group, n = 34 subjects) and those who showed significant decrease of mean blood glucose (HBG group, n = 55 subjects; χ² analysis: P = 0.00001). This threshold blood glucose at recruitment (demarcation point) is 81.8 mg/dL (4.5 mmol/L) at recruitment. Abbreviations: HBG, high blood glucose; LBG, low blood glucose.