Seven-day fasting as a multimodal complex intervention for adults with type 1 diabetes: Feasibility, benefit and safety in a controlled pilot study.

OBJECTIVES Intermittent as well as prolonged fasting are receiving considerable attention and appear favorable in conditions such as metabolic syndrome, type 2 diabetes, and rheumatic diseases. Fasting for individuals with type 1 diabetes (T1D) is generally considered too risky. However, the ability and possibility to change from carbohydrate- to ketone-based fuel supply might be relevant for individuals with T1D. The aim of this patient-led research was to investigate the feasibility, benefit, and safety of a 7-d multimodal fasting intervention in individuals with T1D. METHODS This was a non-randomized controlled pilot study, with 20 participants with T1D and 10 without the disease. Data acquisition took place before, after, and 4 mo after the intervention and daily during intervention. RESULTS Of the individuals with T1D, 19 finished fasting. A mean β-hydroxybutyrate as representative ketone body increased to 2.8 ± 1.9 mmol/L on day 7; whereas average glucose remained between 4.9 (±1.5) and 7.5 (±2.3) mmol/L (89 ± 27 and 136 ± 40 mg/dL). Mean daily insulin dose was adjusted from 24.4 (3-50) IU on the day before fasting to 7.6 (0-26.7) IU on day 7. Quality of life (WHO-5) normalized from 54 (±4.4) to 68.8 (±15; P = 0.01) after fasting. There was a decrease from before until the follow-up 4 mo later of weight from 77.6 (±20.4) to 76.6 (±20.9) kg (P = 0.023) and for body mass index from 27.68 (±7.04) to 26.74 (±7.15) kg/m2 (P = 0.008). Diastolic blood pressure increased from 69.75 (±11.41) to 75.74 (±8.42) mm Hg (P = 0.028) and stayed in a healthy range on average. Fasting-related side effects were all temporary, and slightly more prevalent in those with type 1 diabetes compared with the reference group. CONCLUSIONS This study demonstrated the feasibility, benefits, and safety aspects of a 7-d fast in adults with T1D.