Intermittent Fasting for Adults with Type 2 Diabetes: A Review of the Clinical Effectiveness and Guidelines

Key Message

One before-after study was identified regarding the clinical effectiveness of intermittent fasting for adults with type 2 diabetes. Evidence of limited quality from this study suggested that two weeks of intermittent fasting significantly reduced body weight and body-mass index compared to a standard diet, but these differences were not retained after a two-week follow-up. No significant differences were reported for waist circumference, blood pressure or markers for inflammation (C-reactive protein) and insulin resistance (Homeostasis Model Assessment of Insulin Resistance). A positive relationship was found between the number of hours fasted and morning self-monitored glucose levels reaching target values, but this relationship was not found for afternoon or evening self-monitored glucose levels. Descriptively, the included study found reduced caloric, carbohydrate and fat intake, and higher physical activity levels during the intermittent fasting phase (intervention) when compared to standard diet at both baseline and follow-up phases. No evidence-based guidelines for the use of intermittent fasting for adults with type 2 diabetes were identified. The limited evidence on this topic suggests further research comparing intermittent fasting to standard or low carbohydrate diets is needed in order to determine its place as an intervention for adults with type 2 diabetes.