Background:
One in four Australian adolescents has overweight or obesity with increasing rates of severe obesity. Effective treatment is vital and novel approaches are required. Modified Alternate Day Fasting (MADF) diets in adults are as effective as continuous energy restriction. MADF, with shorter periods of energy restriction and days of habitual energy intake may be more sustainable for adolescents. The aim of this randomised controlled trial (RCT) is to determine if MADF results in a lower BMI z-score after 52 weeks of intervention in adolescents with obesity, compared to a standard hypocaloric diet.
Methods:
We will recruit 186 (93 each arm) adolescents with obesity from Sydney and Melbourne. All participants will undergo a Very Low Energy Diet (VLED) for 4 weeks during Phase 1 of the study. Participants will consume 3-4 meal replacements per day and one low carbohydrate meal. During Phase 2 (weeks 5-16), participants will be randomised to MADF (experimental arm) or a standard hypocaloric diet (active control arm). The MADF protocol includes a VLED 3 days/week (500-600kcal/day) and a standard healthy diet 4 days/week. The standard hypocaloric diet is high fibre, with 40-50% energy from carbohydrate and 20-25% energy from protein, with prescriptive energy levels based on age; 6000-7000kJ/day for 13-14years and 7000-8000kJ/day for 15-17years. Participants will regularly consult with a dietitian, with additional support via phone, text and social media. The primary outcome is change in BMI z-score at 52 weeks.
Discussion:
Obesity during adolescents is associated with increased risk of diabetes and cardiovascular disease into adulthood. This RCT will be the first to compare MADF with a standard hypocaloric diet in adolescents with obesity. Results will inform clinical practice and may assist in reducing cardiometabolic risk factors in this population.
This study is funded by the National Health and Medical Research Council (APP1128317).