The research conducted by authors from North Carolina, US, evaluated the relationship between post-exercise protein intake and glycemia following isoenergetic bouts of moderate intensity continuous training (MICT) or high-intensity interval training (HIIT) among 11 adults with Type 1 diabetes (TD1),and found a trend towards reduced time below range (TBR) of glucose levels with increasing protein intake (p < 0.1).
The authors of the randomised controlled exercise pilot study conclude: “Results suggest that, among people with T1D, following this same nutritional strategy may potentially reduce the risk of post-exercise hypoglycemia, specifically following MICT exercise.”
Regular exercise is crucial for managing diabetes and weight, but many adults with T1D do not engage in regular physical activity due to the fear of low blood sugar (hypoglycemia) during or after exercise.
Nutrition plays a vital role in managing blood sugar levels during and after exercise. While there are established guidelines for carbohydrate consumption, the role of protein intake in managing exercise-related blood sugar levels is less understood.
In the general population, consuming protein after exercise has various benefits, including improved recovery, reduced soreness, increased muscle strength, and fat loss when combined with a reduced-calorie diet.
However, among people with T1D, protein intake can lead to an increase in blood sugar levels, which peak a few hours after consumption and remain elevated for an extended period.
Yet the authors of the new study suggest: “Increasing dietary protein intake following exercise among people with T1D may mitigate declining glycemia following exercise, thereby reducing the risk of hypoglycemia.”
Only two previous studies have investigated the effects of protein intake around exercise on blood sugar levels in people with T1D.
One study with adolescents found that consuming a protein-rich breakfast two hours before exercise helped prevent hypoglycemia during exercise compared to a standard breakfast.
Another study with young adults showed that consuming a protein drink after moderate-intensity exercise reduced the need for glucose to maintain normal blood sugar levels overnight.
However, the authors note: “These studies…were conducted in well-controlled environments and may not fully represent the effects of protein intake in a free-living environment.”
Therefore the new study's main objective was to analyse data from a previous exercise study in adults with T1D and investigate how post-exercise protein intake relates to blood sugar levels following HIIT or MICT.
The study enrolled 14 adults (7 male, 7 female) with T1D between the ages of 18 and 51 years old, and BMIs of 25.1 ± 3.4, aiming to characterise the metabolic, hormonal, and glycemic response to exercise and explore the role of physiological variables (biological sex, lean body mass, visceral fat mass) in modulating the observed responses.
They participated in isoenergetic sessions of HIIT or MICT.
Participants completed food records on the days of exercise and provided continuous glucose monitoring data throughout the study, from which time in range (TIR, 70–180 mg/dL), time above range (TAR, >180 mg/dL), and TBR (<70 mg/dL) were calculated from exercise cessation until the following morning.
The authors used mixed effects regression models, adjusted for carbohydrate intake, diabetes duration, and lean mass, to assess the relationship between post-exercise protein intake on TIR, TAR, and TBR following exercise.
Results showed that no association was observed between protein intake and TIR, TAR, or TBR (p-values ≥ 0.07); however, a borderline significant reduction of −1.9% (95% CI: −3.9%, 0.0%; p = 0.05) TBR per 20 g protein was observed following MICT in analyses stratified by exercise mode.
They do however note that the study had limitations, including a small sample size, self-reported dietary intake, and the lack of insulin dosing data, suggesting that further research is needed to establish a causal relationship and develop practical recommendations for clinical practice.
"Post-Exercise Protein Intake May Reduce Time in Hypoglycemia Following Moderate-Intensity Continuous Exercise among Adults with Type 1 Diabetes"
Authors: F.R. Muntis, et al.