Background: Polycystic ovarian syndrome (PCOS) is the most common reproductive endocrinopathy in women of reproductive age with many associated metabolic symptoms, in particular hyperinsulinemia, insulin resistance and a high lifetime risk of type 2 diabetes mellitus. The effects of time-restricted eating on metabolic profiles have been investigated in many endocrinopathies, but there are minimal data in PCOS.
Methods: This study will investigate the feasibility of time-restricted eating in the management of PCOS, and its effects on insulin levels and other metabolic parameters.
To achieve this, the investigators will recruit 20 patients with PCOS (normal weight, overweight, obese).
In a randomised cross-over design, participants will be observed for two consecutive 12 week periods (with a 4 weeks washout period in between) following either 'time-restricted eating' or 'usual eating', detailed below.
1. 18:6 protocol: 18 hours of fasting and a 6-hours eating window, with no other specific dietary advice. Participants choose their own 6-hour period according to their lifestyle and preference.
2. Usual eating: follow usual eating patterns, no time restriction, no other dietary advice
When fasting, participants are permitted to consume plain water, unflavoured/unsweetened sparkling water, black breakfast tea and black coffee.
Dietary intake will be determined at baseline, at midpoint of each study arm, and at the end of the study using Nutritics software. Participants will self-record dietary intake using the Nutritics 'app'.
The primary endpoints will be serum insulin and feasibility of the intervention as well as safety, acceptability, and compliance with time-restricted eating.
Secondary endpoints will be insulin resistance (Homeostatic Model Assessment for Insulin Resistance (HOMA-IR)), androgens (testosterone, free testosterone, dehydroepiandrosterone sulfate (DHEA-S), androstenedione, 17-Hydroxyprogesterone (17-OHP) and sex hormone binding globulin (SHBG)), appetite (10-point visual analogue scale), hunger/satiety (glucagon-like peptide 1 (GLP-1), grehlin, PYY and oxyntomodulin, fasting glucose, HbA1c, lipid profile, lipoprotein lipid A, apolipoprotein A1, apolipoprotein B, anthropometrics (weight, body mass index, hip and waist circumference), dietary intake (calorie and macronutrient intake; micronutrient intake including iron, calcium; dietary pattern including timing).
Results: Safety and acceptability will be measured by adverse event reporting and measurement of adherence. Paired t-test will be used to assess between baseline and post intervention measurements. Results considered statistically significant if p\<0.05.
Discussion: Time-restricted eating has potential to aid in improvement of insulin resistance in patients with PCOS based on studies in other populations. There is no substantial literature on this subject to date in the PCOS patient cohort, with this being the first randomised study to date. The investigators will discuss the effects of time-restricted eating on insulin levels in the specific population of women with PCOS based on the results.
