Daily vs Intermittent Restriction of Energy: Randomised Controlled Trial to Reduce Diabetes Risk (DIRECT)

This is an open-label, multi-arm, parallel group, sequential, randomized controlled trial which compared the long term effectiveness of intermittent fasting (IF) versus an energy matched moderate calorie restriction (CR) over 18 months, and relative to a non-active intervention standard control (SC) in individuals who are at increased risk of developing type 2 diabetes.
This trial recruited 260 non-diabetic men and women aged 35-75 years, BMI 25−50 kg/m2 with score ≥12 on the Australian Diabetes Risk (AUSDRISK) calculator. Participants were randomized to one of three groups for 18 months: IF (30% of energy needs on fast days), CR (70% of energy needs daily), or standard care (SC) group. All participants visited the clinic fortnightly for weight assessments during active intervention phase (6 months), followed by a 12-month follow-up phase. In addition, all participants underwent blood tests following a 12-hour overnight fast for the "A" visit at Month 0, 2, 6 (active) and 18 (follow up).