From the Guidelines
Intermittent fasting can be beneficial for patients with type 2 diabetes requiring insulin, but it should only be undertaken with close medical supervision to minimize the risk of hypoglycemia and other complications. For these patients, intermittent fasting can improve insulin sensitivity, promote weight loss, and potentially reduce insulin requirements over time [ 1 ]. Common approaches include the 16:8 method (16 hours fasting, 8 hours eating) or the 5:2 approach (regular eating five days, restricted calories two days). Patients using insulin must work with their healthcare provider to adjust insulin dosages during fasting periods to prevent dangerous hypoglycemia, as treatment with insulin or insulin secretagogues requires consistency in timing of meals and carbohydrate content [ 1 ].
Key Considerations for Implementation
- Patients should increase blood glucose monitoring during fasting periods, checking levels at least 4-6 times daily.
- Basal insulin doses may need to be reduced by 15-30% on fasting days, while bolus insulin should be adjusted based on carbohydrate intake during eating windows [ 1 ].
- Patients should break their fast immediately if blood glucose drops below 70 mg/dL.
- Intermittent fasting is contraindicated for pregnant or breastfeeding women, patients with a history of eating disorders, and those with advanced diabetes complications.
- Adequate hydration and balanced nutrition during eating windows remain essential for success with this approach.
Adjusting Insulin Therapy
When adjusting insulin therapy for patients with type 2 diabetes who are undertaking intermittent fasting, it is crucial to consider the pharmacodynamic profile of each insulin formulation [ 1 ]. This may involve titrating basal insulin doses, adjusting the timing of mealtime insulin, or considering the use of rapid-acting insulin analogues for greater flexibility in meal planning. The goal is to achieve optimal glycemic control while minimizing the risk of hypoglycemia and other complications associated with insulin therapy.
From the Research
Benefits of Intermittent Fasting for Patients with Type 2 Diabetes Requiring Insulin
- Intermittent fasting has been shown to be effective in reducing body weight, decreasing fasting glucose, decreasing fasting insulin, reducing insulin resistance, decreasing levels of leptin, and increasing levels of adiponectin in patients with type 2 diabetes 2.
- Some studies have found that patients with type 2 diabetes were able to reverse their need for insulin therapy during therapeutic intermittent fasting protocols with supervision by their physician 2.
- A 12-week intermittent fasting regimen has been compared to usual care in people with type 2 diabetes mellitus receiving insulin therapy, with co-primary outcomes including the difference in the change of HbA1c from baseline to 12 weeks and the difference in the number of participants achieving a combined end point encompassing a body weight reduction of at least 2%, an insulin dose reduction of at least 10% and an absolute HbA1c reduction of at least 3 mmol/mol (0.3%) between the two groups 3.
- The physiological mechanisms underlying the positive effects of intermittent fasting in type 2 diabetes include metabolic transformation, improvement of systemic metabolism, and induction of tissue-specific metabolic adaptations through alterations in the gut microbiota, adipose tissue remodeling, correction of circadian rhythm disturbances, and increased autophagy in peripheral tissues 4.
- Intermittent fasting has been compared to continuous energy-restricted diets for patients with type 2 diabetes mellitus and metabolic syndrome, with similar effects on glycemic control and a better effect on weight loss 5.
Considerations for Implementing Intermittent Fasting
- Patients with type 2 diabetes should consult their physician prior to beginning an intermittent fasting regimen in order to allow for appropriate oversight and titration of the patient's medication regimen during periods of fasting 2.
- The efficacy and safety of intermittent fasting regimens in clinical applications carry a risk of hypoglycemia and require monitoring of blood glucose and timely adjustment of medications 4.
- Further studies with a larger sample size are needed to verify the effectiveness and safety of intermittent fasting in patients with type 2 diabetes 5.