Assessing compliance with Paleolithic diet by calculating Paleolithic Diet Fraction as the fraction of intake from Paleolithic food groups

Background: Dietary compliance assessments are absent in clinical studies on Paleolithic diet. We therefore developed a ‘Paleolithic Diet Fraction’ (PDF), calculated as the fraction of intake from Paleolithic food groups, to assess compliance with Paleolithic diet in a previously reported study. Methods: 29 male patients with ischemic heart disease, impaired glucose tolerance and waist circumference > 94 cm, were randomized to a Paleolithic or Mediterranean-like diet for 12 weeks. Mean daily PDFs were calculated for dietary energy and weight for all participants using four-day weighed food records, and linear regression analysis was performed between PDF and primary outcome measures plus leptin for both diet groups combined. Results: PDFs were just above 80% for the Paleolithic diet group and around 40% for the Mediterranean-like diet group. We found associations between PDF and outcome measures of similar strength as previously reported for group differences, and an association with weight, for which no group difference was previously found. Conclusions: Calculation of PDF demonstrated a mean compliance of just above 80% in the Paleolithic diet group and association studies indicated a clinical relevance for PDF. Trial registration: ClinicalTrials.gov NCT00419497 retrospectively registered.