Against that background, the results of a recent study from the Technical University of Madrid are extremely important. After all, the scientists were able to show that a mere increase in daily physical activity is as effective in boosting obese subjects weight loss efforts as "serious" exercise. The aim of the study was simple: To compare the effects of different physical activity programs, in combination with a hypocaloric diet, on anthropometric variables and body composition in obese subjects.
To this ends, the researchers recruited ninety-six (!) obese (men=48; women =48; age range 18-5
years) participants, who took part in a supervised 22 week program. The subjects were randomized into four groups (the details are described further below):
- strength training (S, n=24),
- endurance training (E, n=26),
- combined strength + endurance training (SE, n=24), and as previously hinted at
- physical activity recommendations (C, n=22).
"The diet was designed to provide 30% less energy than the baseline total daily energy expenditure (DEE), as measured using a SenseWear Pro Armband accelerometer (Body Media, USA). Some 29-34% of energy came from fat, and 50- 55% from carbohydrates, according to the recommendations of the Spanish Society of Community Nutrition (SENC, according to its Spanish initials, and 20% from protein (beyond that outlined in the above recommendations) in order to achieve the body composition benefits observed in different studies and examined in a recent meta-analysis" (Benito. 2015).Dietary counselling was given at baseline and at 12 weeks to resolve questions and to motivate participants sufficiently to comply with dietary advice. All subjects were instructed on how to record their dietary intake using a daily log, and given recommended portion sizes and information on possible food swaps. In addition, nutrition education sessions were given by the dieticians. The goal was to equip the participants with the knowledge and skills necessary to achieve gradual but permanent behaviour changes.
Speaking of behavioral changes,...
While diet was one pillar of the weight loss success of the study participants, exercise was another. You already know that there were three groups. What you don't know, though is what exactly the subjects who had been randomly assigned to the previously listed groups actually did (I quote from th paper by Benito et al., 2015):
- The exercise groups (training 3x per week): The S group followed a circuit involving eight exercises: the shoulder press, squats, the barbell row, the lateral split, bench press, front split and biceps curl, and the French press for triceps. Running, cycling or elliptical (self-selected) exercises were the main components of the session for group E, while group SE followed a combination of cycle ergometry, treadmill or elliptical exercises intercalated with squats, rowing machine, bench presses and front split exercises (15 lifts per set or 45 s for the SE endurance phase).
The exercise training programs were designed taking into account each subject’s muscular strength (MS) and heart rate reserve (HRR). MS was measured in the strength program subjects (S, SE) using the 15-repetition maximum (15 RM) testing method every other day during the week before the intervention period. The volume and intensity of the three training programs were equal and increased progressively during the study. In weeks 2-5, exercise was at an intensity of 50% of the 15RM and HRR, and lasted an overall 51 min and 15 s. In weeks 6-14, exercise was performed at an intensity of 60% of 15RM and HRR, again with a duration of 51 min and 15 s. Finally, in weeks 15-22, exercise was performed at an intensity of 60% of 15RM and RR, with a duration of 60 min.
All groups gained the same amount of lean mass! I find it quite remarkable that all groups gained 5% lean mass - even the endurance and the "control" group which did no prescribed exercise at all, but simply took the stairs and were only "made aware" of the rest of the activity recommendations of the American College of Sports Medicine (ACSM).
- The get active in your everyday lives group: The C subjects followed the hospital’s habitual clinical practice for achieving weight loss: dietary intervention - the same as followed by the exercise training groups -plus being made aware of the general recommendations of the American College of Sports Medicine (ACSM) regarding physical activity.
Thus, the C subjects were advised to undertake at least 200-300 min of moderate-intensity physical activity per week (30–60 min on most, if not all, days of the week). The C subjects were also advised to reduce their sedentary behaviour (e.g., watching television or using the computer) and increase daily activities such as brisk walking or cycling instead of using a car, or climbing stairs instead of using the lift etc.
variables measured using dual-energy X-ray absorptiometry techniques.
|Figure 1: Relative changes in weight, waist and total body fat over the 22-week study period (Benito. 2015).|
The lack of inter-group differences in body composition is probably a direct consequence of the fact that the total physical activity per week during the intervention increased similarly, but not identically in all groups (S: 976±367 MET-min/week; E: 954±355 MET-min/week; SE: 1 329±345 MET-min/week; C: 763±410 MET-min/week). in view of the lack of statistical difference between th exercise groups which got - on average - more exercise than the control group, it is thus not surprising that the 22-week changes in body composition did not differ, either.
- Benito, Pedro J., et al. "Change in weight and body composition in obese subjects following a hypocaloric diet plus different training programs or physical activity recommendations." Journal of Applied Physiology (2015): jap-00928.