|Just look at the guys surrounding you, girls. How on earth will you get bulky if they are training like maniacs and still look like size-zero bans?|
In his review, the scientists focused on comparing changes from treatment program for adults who are overfat based on analysis of aggregated effect size (ES) of inducing changes from 66-population based studies, and 162-studywise groups.
Clark's analysis of this large dataset yielded both, obvious and less obvious results. The realization that "a hypocaloric balance [=dietary restriction] is necessary for changing body composition" (Clark. 2015), for example is hardly surprising.
|Figure 2: The effect sizes of the interventions' effects on insulin, leptin, cholesterol & co yields similar results: The combination of resistance training and diet has (on average) the most favorable effects (Clark. 2015).|
"resistance training (RT) was more effective than endurance training (ET) or combination of RT and ET, particularly when progressive training volume of 2-to-3 sets for 6-to-10 reps at an intensity of ≥75% 1RM, utilizing whole body and free-weight exercises, at altering body compositional measures (ES of 0.47, 0.30, and 0.40 for loss of BM, FM, and retention of FFM respectively)" (Clark. 2015)Now, while this may still be in line with at least some of the mainstream recommendations, Clark's observation that the RT regimen was also more effective at reducing total cholesterol (ES = 0.85), triglycerides (ES = 0.86) and low-density lipoproteins (ES = 0.60), as well as at reducing fasting insulin levels (ES = 3.5) than endurance training or endurance training and resistance training in combination emphasizes how much of a game changer (intense!) resistance training can actually be.
Avoid black and white thinking! Despite the fact that the meta-analysis at hand shows on average that interventions that focus on diet + resistance training are the most effective ones. It would be haphazard to conclude that doing a moderate amount of cardio would be counter-productive. If you use it, to eat more, it may in fact impair your results. If you go for a 20-minute jog at a moderate pace thrice per week, though, this is neither going to burn away muscle mass, nor stalling your fat loss. As discussed below, the lack of additional effects of combined training in the meta-analysis at hand may well be caused by factors that have nothing to do with the often-heard-off ill effects of moderate intensity cardio.
- Clark, James E. "Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18–65 years old) who are overfat, or obese; systematic review and meta-analysis." Journal of Diabetes & Metabolic Disorders 14.1 (2015): 31.
- Cuff, Darcye J., et al. "Effective exercise modality to reduce insulin resistance in women with type 2 diabetes." Diabetes care 26.11 (2003): 2977-2982.
- Donnelly, Joseph E., et al. "Effects of a very-low-calorie diet and physical-training regimens on body composition and resting metabolic rate in obese females." The American journal of clinical nutrition 54.1 (1991): 56-61.