(P16-014-23) Postprandial Glycemic Response and Glycemic Variability During a Short-Term Caloric and Carbohydrate Restriction

Objectives: The primary objective of this study was to determine the impact of short-term caloric restriction with and without carbohydrate restriction on post-prandial glucose (PPG) and glucose variability (GV). 

Methods: Eight healthy, young active and normal-weight (18-25 kg/m2) males, aged 18-40 were recruited for this pilot study. Participants were randomized to a 100 g/d Low-Carbohydrate Diet (LCD) or Standard-Diet (SD). During the baseline (Week 1), participants consumed their habitual diets. Afterwards, they followed LCD or SD for one week of energy balance (week 2), followed by one week of LCD or SD with a caloric deficit of 500 kcal/day (week 3). Throughout the study, participants used a Continuous Glucose Monitoring (CGM) sensor to obtain data for Average Glucose (AG), Mean Amplitude Glucose Excursions (MAGE), Mean of Daily Differences (MODD) and Coefficient of Variability (CV). For data analysis, we used glycemic variability parameters and PPG excursions using mean peak glucose from average post-meal AUC _0-120min to compare diets (LCD vs. SD) and study phases (diet vs. diet + caloric restriction).

Results: The transition from energy balance (week 2) to caloric restriction (week 3) resulted in a significant reduction in mean PPG in both SD (143.6 ± 3.3 mg/dl^-1 vs. 134.2 ± 5.3 mg/dl^-1, p= 0.032) and LCD (133.4 ± 3.7 mg/dl^-1 vs. 115.4 ± 4.3 mg/dl^-1; p=0.026). Reductions following caloric restrictions were greater in LCD (-18.0 mg/dl) when compared to SD (-9.4 mg/dl), resulting in significantly lower mean PPG in LCD vs. SD group in week 3 (p= 0.013).

Additional glycemic variability parameters which were significantly altered by caloric restriction included MAGE (-4.7 ± 4.3, p=0.049), MODD (-4.24 ± 2.3 p=0.041), and CV (-3.7 ± 1.3, p=0.05) in SD and MAGE (-13.7 ± 3.3, p=0.003), MODD (-6.35 ± < 2.3, p=0.04), CV (-7.7 ± 2.3, p=0.043) for LCD.

Conclusions: This study demonstrates that overall glycemic excursions were reduced during a moderate caloric restriction independent of carbohydrate restriction. However, reductions in mean PPG and GV were more pronounced in LCD. Implementing carbohydrate restriction (100 g/day) paired with caloric restriction has the potential to improve glycemic variability and PPG when compared to caloric restriction or carbohydrate restriction alone.

Funding Sources: Data for this study was collected as part of a collaboration with MetaFlow Ltd.