Do different meals affect glucose levels in people using an artificial pancreas?

This study examined the effects of adding protein and/or fat to a meal with a standard amount of carbohydrates, in adults with type 1 diabetes (T1D) using an artificial pancreas (AP). It was determined adding protein and/or fat did not affect glucose levels over time, but did influence the timing of spikes in glucose levels, and increased insulin requirements.

An insulin pump continuously delivers insulin, without the need for multiple daily injections. Some pumps also have a continuous glucose monitoring (CGM) system. CGMs give the patient up-to-date information about their glucose levels by placing a sensor in the fat just under the skin. APs use information from a CGM system to automatically control the release of insulin from a pump. A ‘bolus’ injection may also be given before meals. Whether this needs to be adjusted for the protein and/or fat content of a meal in people using APs is not certain.

15 adults with T1D participated in this study. They were given four different breakfast meals on different mornings. All meals had the same amount of carbohydrates. The standard meal was mainly carbohydrates, with no added protein or fat. There was also a high-protein (HP) meal, a high-fat (HF) meal, and a meal high in protein and fat (HPHF). They were monitored for 5 hours after eating a meal.

There was no difference between any of the meals for glucose levels over 5 hours. Average glucose levels were also similar after all meals. There was no difference in the highest glucose level (glycemic peak) measured after all meals. However, the glycemic peak occurred roughly 40 minutes later in the HPHF meal than for the standard meal. Glucose excursions (sudden spikes in glucose levels) after the standard meal were higher after 30 and 60 minutes, and smaller after 210 and 300 minutes, compared to the HPHF meal. Glucose levels tended to vary more over the 5 hours after eating the standard meal, compared to the HP, HF, and HPHF meals.

Total insulin requirements were 39% higher for the HPHF meal compared with the standard meal.

The study concluded that in people with T1D using APs, adding fat and/or protein to a meal does not affect glucose levels over 5 hours, but delays the glycemic peak and results in higher late glycemic excursions, less variability in glucose levels, and increased insulin requirements.

This study only involved 15 participants. Thus, the results may not apply equally to all people with T1D.

Discuss the impact of different meal types on glucose levels with your physician.