Meal sequence significantly impacts post-meal glucose and insulin levels
Allulose StoreAlpana P. Shukla, Katalin E. Tamás, Radu G. Iliescu, Louis J. Aronne, 2015.
Source: Diabetes Care
Postprandial hyperglycemia is an important therapeutic target for optimizing glycemic control and mitigating the proatherogenic vascular environment characteristic of type 2 diabetes.
Existing evidence suggests that the quantity and type of carbohydrates consumed influence blood sugar levels, and that the total amount of ingested carbohydrates is the primary predictor of glycemic response (1).
Previous studies have shown that pre-meal consumption of whey protein, as well as altering the macronutrient composition of a meal, reduces post-meal glucose levels (2, 3, 4).
However, limited data are available on the effect of meal order on postprandial glycemia in patients with type 2 diabetes (5).
In this pilot study, we investigated the effect of meal order – a typical Western meal containing vegetables, protein, and carbohydrates – on postprandial glucose and insulin fluctuations in overweight/obese adults with type 2 diabetes.
A total of 11 subjects with type 2 diabetes treated with metformin (6 women, 5 men) were studied in a crossover trial.
The mean age was 54 ± 9 years, and the BMI was 32.9 ± 5.
The mean duration of diabetes was 4.8 ± 2.4 years, and the mean HbA1C level was 6.5 ± 0.7%.
After a 12-hour overnight fast, study subjects consumed an isocaloric meal (628 kcal: 55g protein, 68g carbohydrate, and 16g fat) with identical composition on two separate days, one week apart.
In the first trial, the meal order was carbohydrate (ciabatta bread and orange juice), followed 15 minutes later by protein (skinless grilled chicken breast) and vegetables (lettuce and tomato salad with low-fat Italian vinaigrette and steamed broccoli with butter); the meal order was reversed one week later.
Blood samples were taken at baseline (immediately before the meal) and 30, 60, and 120 minutes after the start of the meal to measure glucose and insulin levels.
Glucose levels
Mean postprandial glucose levels decreased by 28.6%, 36.7%, and 16.8% at 30, 60, and 120 minutes, respectively.
The incremental area under the curve (iAUC 0–120) was 73% lower when vegetables and protein were consumed before carbohydrates, compared to the reversed meal order:
Insulin levels
Postprandial insulin levels at 60 and 120 minutes, and iAUC 0–120, were also significantly lower when protein and vegetables were consumed first:
The graph shows that the insulin level after the meal pattern with carbohydrates last is, on average, approximately 40% lower compared to the pattern with carbohydrates first at the measured time points.
The magnitude of the difference varies over time:
- Approximately 32% lower at 30 minutes
- Approximately 49% lower at 60 minutes
- Approximately 40% lower at 120 minutes
When calculating the incremental area under the curve (iAUC 0–120), a significant difference is observed between the two meal orders.
Applying the trapezoidal rule based on the values read from the graph:
- Carbohydrate first: iAUC value is 10 155
- Carbohydrate last: iAUC value is 5 190
This means that timing carbohydrates to the end of the meal approximately reduces the postprandial insulin load (iAUC) by 49% compared to consuming carbohydrates first.
Conclusions
In this pilot study, we demonstrated that the timing of carbohydrate intake during a meal has a significant impact on postprandial glucose and insulin fluctuations.
The magnitude of the meal order's effect on glucose levels is comparable to what has been observed with pharmacological agents targeting postprandial glucose.
Furthermore, the reduced insulin fluctuations observed in this experimental setting suggest that this meal pattern may improve insulin sensitivity.
One limitation of the study is that glucose and insulin responses were analyzed only up to 120 minutes after meal intake, as this study was designed to test postprandial glucose levels measured in practice by patients with type 2 diabetes.
Further, longer follow-up studies are needed to describe the full effect, including delayed effects and the mechanisms of the glycemic effect of meal order.
In contrast to traditional dietary advice for diabetes, which is largely restrictive and focuses on "how much" and "what not to eat," this pilot study suggests that an improvement in glycemic levels can be achieved by optimizing the timing of carbohydrate intake during a meal.
References
1.) Sheard NF, Clark NG, Brand-Miller JC, et al.
Dietary carbohydrate (amount and type) in the prevention and management of diabetes: a statement of the American Diabetes Association. Diabetes Care 2004;27:2266–2271
2.) Frid AH, Nilsson M, Holst JJ, Björck IM.
Effect of whey on glycemia and insulin response to composite breakfast and lunch meals in type 2 diabetic subjects.
Am J Clin Nutr 2005;82:69–75
Metabolic response to a high-protein diet in individuals with type 2 diabetes.
Nutr Metab (London) 2004;1:6
4.) Jakubowicz D, Froy O, Ahrén B, et al.
Incretin, insulinotropic, and glucose-lowering effects of whey protein preload in type 2 diabetes: a randomized clinical trial.
Diabetologia 2014;57:1807–1811
Eating order diet reduced the postprandial glucose and glycated hemoglobin levels in Japanese patients with type 2 diabetes.
J Rehabil Health Sci 2010;8:1–7
