Effect of Low-calorie Diet and Orange Juice on Body Weight and Metabolic Parameters of Obese Subjects

Seventy-eight obese subjects aged 36 ± 1 years and BMI of 33 ± 3 kg were randomly divided into two parallel groups: (1) orange juice (n = 39), composed of individuals subjected to a diet low caloric diet and plus intake of 500 ml orange juice; (2) control (n = 39) composed of individuals subjected to a diet low in calories. The recruitment process began in September 2015, the intervention was carried out from October 2015 to January 2016, and the data analysis started in February 2016. The sample number took into account variances on body weight with a type I error α = 0.05 and a type II error β = 0.2 (80% power). The minimum sample size should have 36 individuals per group (n = 72), considering an approximately 15% dropout rate. Thus, the final sample size of study was constituted by 39 individuals per group (n = 78). Primary and secondary endpoints were the reduction of weight and modification of the levels of obesity-related metabolic biomarkers, respectively. Normality and homogeneity of data were tested. T-test was conducted to identify possible differences between OJ and control groups at baseline. A linear mixed-effects model was apply to determine the time effect within and between groups (post hoc), and P significance was set up ≤ 0.05. The assessment of body composition, metabolic biomarkers and food intake were analyzed over a 12-week intervention.

Inclusion criteria

• 30 > BMI < 40 kg/m2

Exclusion criteria

• Dieting last year,
• Use of drugs, vitamins and dietary supplements
• Alcohol consumption (> 20 g alcohol/d)
• Intense physical activity (> 5 hours/week).