Feasibility of Time-Restricted Eating in the Treatment of Type 2 Diabetes

The overall aim of this pilot study is to examine feasibility of a 12-week 10-hour time-restricted eating intervention in individuals with overweight or obesity and type 2 diabetes. The results of the pilot study will inform recruitment, design and delivery of a future long-term time-restricted randomized controlled trial.

In people with type 2 diabetes (T2D), weight loss is associated with improved glycaemic control and markers of cardiometabolic function as well as reduced use of antidiabetic medicine. Beyond pharmacological treatments, current strategies to reduce body weight and improve glycaemia include energy-restricted diets and increased physical activity.

Lifestyle interventions are complex, affecting many aspects of peoples' daily life. Dietary restrictions often result in rapid weight loss, but the weight is gradually regained by many. Barriers to implement and maintain dietary changes include lack of knowledge, support, and insights into the type and amount of foods eaten. Previous lifestyle interventions targeting weight loss in T2D show efficacy for improving markers of metabolic risk, including weight and glycaemia during the intervention, but relapse of behavior and weight regain are often present.

One reason may be that the intervention is not modified according to the needs of the target group. Often, weight loss interventions are shaped by a 'one size fits all' model where both individual capabilities and motivation as well as social and contextual factors are more or less ignored. A user-based design will facilitate enrolment of participants and likely promote uptake and maintenance of the intervention among participants.

Intermittent fasting regimens have been suggested as efficient strategies for improving cardiometabolic health to a greater extent than can be attributed to the reduction in energy intake alone. Time-restricted eating limits the time available for food intake to typically 4-10 hours/day without other dietary restrictions and has been put forward as a novel, acceptable, and safe lifestyle modification and has shown promising effects on body weight, glucose metabolism, appetite, and cardiometabolic health in individuals at high risk of T2D.

The overall aim of this pilot study is to examine feasibility of a 12-week 10-hour time-restricted eating based intervention in individuals with overweight or obesity and T2D. Participants will attend visit 1 (baseline), visit 2 (8 weeks after baseline) and visit 3 (12 weeks after baseline). The study consists of 8 weeks of strict time-restricted eating, followed by 4 weeks of individually adjusted time-restricted eating.

Specific aims are:

1. To assess adherence and participants' experiences, needs and barriers with an 8-week strict time-restricted eating period, followed by a 4-week period with an individually adjusted time-restricted eating based intervention
2. To examine whether intervention components are delivered by health care professionals as intended
3. To explore if intervention support components are acceptable, useful and sufficient for the participants
4. To study recruitment processes and retention, and related barriers and facilitators
5. To evaluate examination days

Eligibility Criteria:
Inclusion Criteria:

* Age: ≥18 years
* Overweight or obesity (BMI ≥25 kg/m2)
* T2D with HbA1c \>53 mmol/mol
* Habitual eating window ≥12 h/day (incl. foods/snacks and energy-containing beverages)
* Associated with the T2D clinic at Steno Diabetes Center Copenhagen (SDCC) or Hvidovre Hospital

Exclusion Criteria:

* Weight loss \>5kg last 3 months
* Bariatric surgery or planned bariatric surgery within study duration
* Use of fast acting insulin and combination insulin products
* Unable or unwilling to adhere to time-restricted eating; for instance, due to competing medical conditions.
* A wish to adhere to Ramadan
* For women: current/planned pregnancy or lactation
* Alcohol or drug abuse (judged by investigator) or treatment with disulfiram
* Severe hypoglycaemia within last year (Severe hypoglycaemia, as defined by the American Diabetes Association, denotes severe cognitive impairment requiring external assistance for recovery)
* Inability to understand written and oral information in Danish.
* Diagnosed with an eating disorder in the past 3 years
* Medical condition which, based on investigators assessment, challenges participation including but not limited to severe heart, vascular or lung disease, cancer, chemotherapy, psychiatric gastrointestinal, rheumatic or endocrine diseases etc.
* Concomitant participation in other intervention study