As fasting can raise the risk of low blood sugar in those with Type 2 diabetes, it’s generally recommended that those with the health condition consult their doctor before attempting any type of fasting regime. For those with Type 2 diabetes, it’s also important to evaluate the appropriateness of performing consecutive fasting days as it may further increase the possibility of low blood sugar (hypoglycemia). Any decision about modifying medications during fasting days should also be made with a doctor.
However, a recent study from New Zealand offers some encouraging results for those with Type 2 diabetes looking to adopt a fasting regime for the purposes of losing weight. The study found fasting two consecutive days was associated with a lower-than-expected risk of hypoglycemia in participants with Type 2 diabetes.
The aim of the study was to test whether a two-day fast during the week (five days fed and two days fasted) in individuals with Type 2 diabetes would increase the risk of hypoglycemia more than non-consecutive days of fasting. During this study, participants remained under close supervision of a physician, and their medication was adjusted accordingly.
Consistent with other research on intermittent fasting, the study found a clinically significant reduction in weight, fasting glucose and hemoglobin A1c, which is a longer-term marker of blood glucose.
In this study, researchers found that the risk of having a hypoglycemic event was not different between consecutive and non-consecutive fasting days. Importantly, there were no episodes of severe hypoglycemia, and most participants did not experience hypoglycemia. These observations suggest that the risk of hypoglycemia appears to be more dependent on individual characteristics rather than the pattern of fasting.
The study recruited obese adults with Type 2 diabetes who were taking medication for diabetes and randomised them into either consecutive or non-consecutive days of fasting on two days per week for 12 weeks. The participants were free to choose which day of the week to fast; this could vary from week to week to allow flexibility and improve adherence.
Interestingly, the study reported a small, but statistically significant, improvement in self-reported quality‐of‐life rating between baseline and week 12. While special care is required by both the patient and the doctor in implementing intermittent fasting, the same is true for any weight loss approach. Low-calorie diets have long been advocated for those with type 2 diabetes under the supervision of their doctor.
These results suggest that a person with type 2 diabetes can include intermittent fasting as an effective alternative to the traditional approach of a continuous low-calorie diet for weight loss.
Corley BT, Carroll RW, Hall RM et al. Intermittent fasting in Type 2 diabetes mellitus and the risk of hypoglycaemia: a randomized controlled trial. Diabet Med. 2018 May;35(5):588-594.