From the Guidelines
For individuals with diabetes, the highest normal postprandial glucose level should not exceed 180 mg/dL (10 mmol/L), as recommended by the most recent and highest quality study 1. This threshold is crucial for distinguishing between adequate glycemic control and potential complications associated with diabetes. The American Diabetes Association recommends targeting postprandial plasma glucose levels below 180 mg/dL for individuals with diabetes, with individualized goals based on factors such as age, comorbidities, and risk of hypoglycemia 1. Key factors that can affect postprandial glucose levels include:
- Meal composition (carbohydrate, fiber, fat, and protein content)
- Physical activity following the meal
- Individual patient considerations, such as duration of diabetes, age, and life expectancy It is essential to note that postprandial glucose measurements should be made 1-2 hours after the beginning of the meal, generally peak levels in patients with diabetes 1. While the evidence from earlier studies 1, 1, and 1 supports the recommendation of targeting postprandial glucose levels below 180 mg/dL, the most recent and highest quality study 1 provides the strongest evidence for this threshold. Therefore, targeting postprandial glucose levels below 180 mg/dL (10 mmol/L) is the most appropriate recommendation for individuals with diabetes, based on the current evidence 1.
From the Research
Postprandial Glucose Levels
- The highest normal postprandial glucose level is a topic of discussion in several studies 2, 3, 4, 5, 6.
- According to a study published in 2021, the highest postprandial mean plasma glucose was seen at 90 minutes after breakfast (137.50 mg/dl), at 60 minutes after lunch (137.80 mg/dl), and 60 minutes after dinner (134.50 mg/dl) 2.
- Another study from 2003 suggests that isolated postprandial hyperglycemia (2-hour postprandial glucose level >140 mg/dL) is associated with a 2-fold increased risk of death from cardiovascular disease 5.
- A study from 2007 mentions that the target 2-hour post-prandial blood glucose level is <8.0 mmol/L (<144 mg/dL) 6.
- The American Diabetes Association defines normal postprandial glucose levels as less than 140 mg/dl (5,4).
Comparison of Postprandial Glucose Levels
- A study published in 2021 compared postprandial glucose levels at different time points after meals and found that the upper limit plasma glucose levels were most frequently exceeded at the 90th minute after each meal 2.
- Another study from 2015 found that the highest postprandial blood glucose most often occurred post-dinner (44% of participants) and greatest postprandial increments post-breakfast (46% of participants) in all regions 3.
- The studies suggest that postprandial glucose levels can vary depending on the type of meal, individual characteristics, and regional differences 2, 3, 4, 5, 6.