Subjects
The sample was composed of 120 Caucasian healthy adult male volunteers from the area of Andalusia (Spain) (age: 40.02 ± 11.1 yrs; height: 176.4 ± 6.4 cms; weight: 102.4 ± 14 kgs). All the patients were recruited from two private clinics, to which the men went to lose weight.
For a mean of the overall differences of fatty mass between the three types of physical activity of -1.06 kg and a typical deviation of the differences of 1.76kg [26] (that represents a size to the effect of -0,602), a power of 80% and a 95% confidence, a minimum sampling size of 12 individuals per each group was estimated. This size was raised by 10% to cushion the effect of the possible losses (n=39). Finally, 68 individuals began the study and 15 abandoned, with 51 men completing the screening.
All the participants reported that they did not perform any special physical activity, so they were classified as sedentary. The study expected men who were listed as overweight or obese according to body mass index (BMI, calculated as kg / m2) of ≥25). More detail on the inclusion methodology and information on the interviews carried out can be found in our previously published study [27].
Men with the following pathologies or special conditions were excluded from the study: Body fat percentage<25% (lowest limit, a criterion that defines a man as being obese) [28]; suffering from kidney failure; being underage; presenting normal weight (BMI ≤ 25) and declaring that is physically active at the beginning of the treatment. The inclusion criteria were: to be obese according to body fat percentage, being sedentary, and not having attended a diet in the six months before the start of treatment. The flow chart of the participants is presented in Figure 1. This study was approved by the bioethical committee, in the Department of Health at the Regional Government of Andalusia (Act no.284, ref.4156).
Subject randomization
After obtaining the written informed consent, and completing initial screening tests, subjects were assigned to one of three groups: light physical activity (LPA), moderate physical activity (MPA), and intense physical activity group (IPA), through standard computer-based procedures (random number generator). LPA group followed an HP diet without prescription of physical activity (n = 24), MPA group that in addition to following the same diet, was assigned to performing moderate physical activity (n = 21) and IPA group (n = 23) that followed the same diet and was assigned to performing intense physical activity.
Testing sessions
The initial assessment was conducted out in the 24-48 hours before the opening of the intervention. The patients were attended up during the time of the study after the overnight fast and always on the same day and time of the week to minimize variability between sessions. The initial evaluation included a completed anthropometric study: height, total body weight, total BF, muscle mass (MM), and body water. These parameters were all listed in a weekly session together with the PA data.
Dietary intervention
Subjects were provided with customized dietary plans designed by an experienced nutritionist (A.H.R). The daily energy requirements were determined by estimating the energy expenditure as previously reported Harris-Benedict [29]:
Basal metabolic rate = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) – (6.755 × age in years).
A multiplier factor of 1.5 was applied to the value resulting in the equation in those subjects carrying out physical activity [30]. During a period of 24 weeks, all the subjects followed a diet with a distribution of macronutrients: 25-30% proteins, 40-45% carbohydrates, and 30-35% fat. The moderate-fat restricted-calorie Mediterranean diet is rich in vegetables and low in red meat, with poultry and fish replacing beef and lamb, with a goal of no more than 35% of calories from fat. This diet is based on the recommendations of Willett and Skerrett [31]. The diet of this study was hypocaloric with a reduction of 500 kcal/day during the treatment period to achieve a weekly weight loss of 400 grams, an amount that is a safe, achievable, and clinically meaningful goal for weekly weight loss [32]. Dietary protein intake was set at 1.8 g/kg of body mass, as higher protein consumption has been shown to help offset losses in lean tissue mass and promote greater adherence to the nutritional regimen [33]. No vitamins or other nutritional complements were prescribed. After being included in the study, each man participated in a 1-hour seminar in which the Dietitian-Nutritionist instructed on how to make a proper selection of food. The menu proposed was valid for 1 week, and a new diet was provided to each subject in the weekly follow up meeting. The energy and nutritional intake were evaluated by the program Dietowin® (Dietowin 8.0, 2015) [34].
Exercise training intervention
To better high compliance with the exercise regimen, subjects were required to report their performed training (including total steps per day) to the research staff for supervision every week for 24 weeks. LPA is considered as being light, requiring an expenditure of 1-4 Metabolic equivalent units (METs) [35]. The MPA group had to reach 10,000 steps a day on average, at a moderate to vigorous pace, at around 60% of VO2max. The energy expenditure in this group equals 5-8 METs units [36]. The IPA group had to complete 3 resistance training weekly based on the BodyPump methodology [37]. The energy expenditure in this group is over 8 METs.
Anthropometric and body composition measurements
Body fat percentage (%BF), MM, and the percentage of water (%W) were considered as being result variables and were monitored and recorded by multifrequency electrical impedance (BWB-800A, Tanita Corp. USA), previously validated [38]. This method is based on a 3-compartment model capable of evaluating %BF, MM, and bone mineral content. Also, the percentage difference of each dependent variable collected in the control meetings was recorded and compared to the first consultation, to evaluate the changes produced. The independent variables recorded were: age (years), height (cm), weight (Kg), and BMI (Kg/m2). The anthropometric measurements were taken following the recommendations of the standardized anthropometry handbook [39], and by professionals, to reduce the coefficient of variation. Each measurement was noted at 3 different times, calculating the mean value. All the quantitative variables were measured with a precision of 0.1. For the height, a stadiometer was used (SECA 213).
Statistical analyses
The quantitative variables have been presented with the mean and the standard deviation, and the qualitative ones in frequencies and percentages.
To contrast the goodness of fit with a normal distribution of data from quantitative variables, the Kolmogorov-Smirnov test with the Lilliefors correction was used. For the bivariate hypothesis, the Student's t-test was performed for two means, while for the qualitative variables the Chi-square and Fisher's exact tests were employed when necessary. Likewise, for the analysis of three or more means, the ANOVA of repeated means determined the effects of the intervention at the basal moment, at 3 and at 6 months, and the correlation between the quantitative variables was verified by the coefficient of Pearson correlation (r). Finally, if the normality or homoscedasticity criterion was not met for ANOVA, Kruskal-Wallis test was performed.
To adjust the likely impact of physical activity on the body composition and its possible role as a confounding factor, adjusted linear regressions were made for each body composition variable (% GC and MM) and weight, calculating the standardized Beta coefficients. To determine the goodness of fit of the models, the standard error, the adjusted coefficient of determination, the F statistic, the linearity analysis and the residuals were analysed.
For all the statistical analyses, an alpha error of less than 5% was accepted (p<0.05) and a 95% confidence interval was calculated. For the statistical analysis, IBM SPSS Statistics software version 22.0 was used.