Effects of Short-Term Low-Calorie Ketogenic Diet on Biochemical and Anthropometric Parameters in Women With Polycystic Ovary Syndrome

This study was conducted on patients who applied to a nutrition and diet consultancy center in İstanbul.All patients provided written informed consent before the start of the study and after receiving a detailed explanation of the procedures. The sample size of this study was that of Paoli et al. (19) according to the reference study were taken as d: 1.737 and SD: 2.1 for the change parameter observed in the BMI level, and with a 95% confidence interval,1-β: 0.95 and α: 0.05 were determined as at least 7 individuals in the G*Power program.

Exclusion Criteria: Those with any endocrine disorders other than PCOS, chronic liver or kidney disease, hypertension, hyperuricemia, heart failure, infarction or cerebrovascular disease, pregnant and breastfeeding women, those with severe psychiatric disorders, oncological diseases, those using medications that may affect biochemical parameters, and individuals with special dietary needs were excluded in this study.

General Plan of the Study: During the study, four follow-up interviews were held at 7-10-day intervals to monitor participants' diet compliance and body composition changes.During the first meeting, information was provided verbally and in writing regarding the purpose and scope of the study, and an informed consent form was signed. The second interview was held on the second or third day of menstruation. During this meeting, blood was taken from the individuals to analyze biochemical parameters, and then their anthropometric measurements were taken and LCKD was given. Additionally, to determine whether LCKD was not applied before the intervention, a urine ketone test was performed, wherein urine samples were examined for the presence of ketones. During the third interview, urine ketone test was performed to evaluate participants' compliance with the diet, and body composition changes were monitored. During the study, to track their food consumption, participants shared photos of the meals they consumed with the researcher. The fourth and final interview was conducted on the second or third day of the first menstrual period after the LCKD intervention started. The presence of ketosis was determined by examining the urine ketone level again. Subsequently, blood was taken for basal hormone and biochemical measurements, anthropometric measurements were evaluated for the last time, and the LCKD intervention was completed.This intervention study was conducted between two menstrual cycles.

Planning a Ketogenic Diet Intervention: A personalized LCKD was planned. Daily energy requirement is the sum of basal metabolic rate, physical activity factor (1.4), and thermal energy of food (10%). Mifflin-St. Joer's equation was used to determine the basal metabolic rate. Total daily energy requirement was reduced by 500 calories. Castellana et al. suggested that the macronutrient content of the LCKD was calculated as carbohydrates of <20 g/day and protein of 0.8-1.2 g/kg/day. It is calculated according to the individuals' carbohydrate and protein needs, with the remainder of the total energy coming from fat. Daily fat consumption is >30-40 g/day, as in typical LCKDs (Castellana et al., 2020). Participants were allowed to eat unlimited green leafy vegetables, cruciferous vegetables, squash, and cucumbers during the intervention.

This study was conducted on patients who applied to a nutrition and diet consultancy center in İstanbul.All patients provided written informed consent before the start of the study and after receiving a detailed explanation of the procedures. The sample size of this study was that of Paoli et al. (19) according to the reference study were taken as d: 1.737 and SD: 2.1 for the change parameter observed in the BMI level, and with a 95% confidence interval,1-β: 0.95 and α: 0.05 were determined as at least 7 individuals in the G*Power program.