Effects of alternate day calorie restriction and exercise on cardio-metabolic risk factors in overweight and obese adults: An exploratory randomized controlled study

Background: It has been recognized that alternate day calorie restriction (ADCR) or exercise has positive effects on cardio-metabolic risk factors. It is unclear whether the combined effect of ADCR and exercise (aerobic + resistance training) influences risk. We investigated effects of an 8-week ADCR and exercise program (aerobic + resistance training) on cardio-metabolic risk factors in overweight and obese adults. Methods: This study randomized 45 overweight or obese but healthy adults (F = 26, M = 19; aged about 32 to 40 years) into 4 groups: ADCR (n = 13), exercise (n = 10), exercise plus ADCR (n = 12), and control (n = 10) for 8 weeks. Body composition, blood lipids profile, and insulin resistance were measured. The intention to treat (ITT) method was used to analyze all participants that were randomized. Results: A total of 35 participants completed the trial (78%). Body weight, body mass index, waist circumference, fat mass and percent body fat were reduced in the exercise plus ADCR group (- 3.3 ± 2.4 kg, p < 0.01; - 1.3 ± 1.0 kg/m², p < 0.01; - 4.1 ± 3.9 cm, p < 0.01; - 2.7 ± 2.0 kg, p < 0.01; - 2. 5 ± 2.2%, p < 0.01). Insulin, glucose, homeostasis model assessment insulin resistance and triglyceride (- 2.9 ± 4.1 μIU/ml, p < 0.05; - 10.9 ± 16.9 mg/dl, p < 0.05; - 0.9 ± 1.3, p < 0.05; - 43.8 ± 41.9 mg/dl, p < 0.01) decreased in the exercise plus ADCR group only. Conclusions: ADCR and exercise both proved to be beneficial, but the combined intervention was most effective at inducing beneficial changes in body weight, body composition, glucose, insulin, insulin resistance and triglyceride in overweight and obese adults. Trial registration: ClinicalTrials.gov: NCT03652532, Registered August 28, 2018, 'retrospectively registered'.