Diet and Meal Pattern Determinants of Glucose Levels and Variability in Adults with and without Prediabetes or Early-Onset Type 2 Diabetes: A Pilot Study

Abstract

This observational pilot study examined the association between diet, meal pattern and glucose over a 2-week period under free-living conditions in 26 adults with dysglycemia (D-GLYC) and 14 with normoglycemia (N-GLYC). We hypothesized that a prolonged eating window and late eating occasions (EOs), along with a higher dietary carbohydrate intake, would result in higher glucose levels and glucose variability (GV). General linear models were run with meal timing with time-stamped photographs in real time, and diet composition by dietary recalls, and their variability (SD), as predictors and glucose variables (mean glucose, mean amplitude of glucose excursions [MAGE], largest amplitude of glucose excursions [LAGE] and GV) as dependent variables. After adjusting for calories and nutrients, a later eating midpoint predicted a lower GV (β = -2.3, SE = 1.0, p = 0.03) in D-GLYC, while a later last EO predicted a higher GV (β = 1.5, SE = 0.6, p = 0.04) in N-GLYC. A higher carbohydrate intake predicted a higher MAGE (β = 0.9, SE = 0.4, p = 0.02) and GV (β = 0.4, SE = 0.2, p = 0.04) in N-GLYC, but not D-GLYC. In summary, our data suggest that meal patterns interact with dietary composition and should be evaluated as potential modifiable determinants of glucose in adults with and without dysglycemia. Future research should evaluate causality with controlled diets.

Keywords: continuous glucose monitoring; diet composition; dysglycemic; meal timing; normoglycemic.

Figure 1

Glucose excursions over a 2-week period. 2-week continuous glucose monitoring (CGM) daily glucose measurements synchronized across the two groups. Glucose parameters did not differ significantly between groups (Table 2). Red dashed line = indicates the threshold for interstitial glucose readings above 200 mg/dL.

Figure 2

Diet and eating pattern (A) and their variability (B) as predictors of glucose parameters in the entire sample (merged) and subgroup analyses. Summary of behavioral predictors of glucose parameters. Eating patterns were adjusted for caloric intake, carbohydrate (gr), protein (gr), total fat (gr), sugar (gr), fiber (gr) and alcohol (gr). (A) Diet and eating pattern behavior over two weeks as predictors of mean glucose and glucose variability. (B) Diet and eating pattern behavior variability over two weeks as predictors of mean glucose and glucose variability. Green boxes indicate significant positive predictions; red boxes indicate significantly negative predictions. Data analyzed using a generalized linear model. Significance set at 0.05. Abbreviations: CHO—carbohydrate; EO—eating occasion; GV—glucose variability defined as glucose SD; LAGE—largest amplitude of glucose excursion; MAGE—mean amplitude of glucose excursion; SD—standard deviation.