Reduced Carbohydrate Diet Influence on Postprandial Glycemia—Results of a Short, CGM-Based, Interventional Study in Adolescents with Type 1 Diabetes

Abstract

Therapy for type 1 diabetes (T1DM) focuses on maintaining optimal blood glucose levels, achieved with intensive insulin treatment, proper nutrition, and physical activity. The aim of this study was to investigate postprandial glycemic changes under low (30%) and standard (50%) carbohydrate diets in adolescents with T1DM. A single-center cross-over nutritional study was conducted, during which 26 adolescent patients provided 220 continuous glucose-monitored (CGM) meals data from the two consecutive 3-day nutritional plans. Overall, the 50% carbohydrate diet was associated with higher postprandial glucose variability in the small meals (afternoon snacks, second breakfast) and greater postprandial peaks for other meals (breakfast, dinner, supper). Nevertheless, after the adjustment of a patient’s individual clinical variables (age, Tanner classification, glucose disposal rate), we observed that mean postprandial glucose was higher for afternoon snacks and lower for suppers in the 30% carbohydrate diet. Although a 30% carbohydrate diet seems to offer better postprandial glycemia, it requires additional attention from the physician and patient when it comes to modifying daily carbohydrate intake. Increased fat/protein content and size of the main meal lead to a prolonged postprandial glycemic response, which may affect the insulin treatment and result in suboptimal glycemic control.

Postprandial Glucose Variability Following Typical Meals in Youth Living with Type 1 Diabetes

“…Our models also control for multiple factors likely to affect postprandial glycemic variability in youth (e.g., youth’s HbA1c, glucose level at the start of the meal, insulin on board, grams of fiber, grams of carbohydrates, and either SD or CV of glucose levels in the 24 h prior to meals), which may enhance the scientific rigor of our findings. Our results specific to carbohydrate content are generally consistent with the published trial data showing greater postprandial glycemic variability following standardized meals that were higher in carbohydrate content [ 5 , 6 ]. Moreover, our results echo findings from a small observational study among very young children with T1D wherein researchers found greater glycemic variability following free-living meals that were higher in carbohydrate content [ 12 ].…”

“…Though there are a few published trials showing associations between greater carbohydrate, fat, and protein content of meals and greater postprandial glycemic variability in youth with T1D [ 5 , 6 ], these trials used small samples and standardized meals, which may limit their generalizability and clinical application. Our analyses of the T1DEXIP study data provide a unique opportunity to examine these associations using real-world data.…”

“…When exploring how meals of different macronutrient content relate to postprandial glucose variability in youth with T1D, most of the existing studies have been small and used standardized meals [ 5 , 6 ]. Thus, we extend the literature exploring these associations in a large sample of youth consuming their normal nutrient intake during this observational study.…”

“…Notably, in our sub-analyses, insulin modality, exercise in the postprandial period, and exercise intensity did not appear to influence the relationship between mealtime macronutrients and postprandial glycemic variability. A future direction may be to conduct another large observational study of free-living meals in youth with T1D, this time extending the postprandial window to up to five hours to closer approximate controlled studies [ 5 , 6 ]. This study provides further evidence underscoring the potential impact of targeting diet and carbohydrate intake closely approximating the dietary guidelines [ 1 , 18 ] as two methods that may help to reduce postprandial glycemic variability in youth with T1D.…”

“…For instance, in a small randomized cross-over trial that included four test meals containing the same carbohydrate amount, Smart et al [ 5 ] found youth with T1D experienced greater postprandial variability following the meal that was high in both protein and fat compared to the meal that was low in protein and fat. Moreover, a recent small clinical trial reported greater glycemic variability following test meals containing 50% of total daily energy from carbohydrates compared to 30% of total daily energy from carbohydrates [ 6 ]. In adolescents with T1D, researchers have yet to examine how the macronutrient content of free-living meals might relate to youths’ postprandial glycemic variability.…”