"At the end of 12 weeks, the women were all significantly more aerobically fit thanMore than two-thirds of the women became fatter as a result of doing "cardio" for thirty minutes three times a week. This study reminds me of some videos Brad Pilon and Craig Ballantyne made where Brad shovels down pizza while Craig runs on the treadmill. In 3 minutes, Brad consumed approximately 1000 total calories, while Craig burned only 43 calories.
they had been at the start. But many were fatter. Almost 70 percent of the women had added at least some fat mass during the program, and several had gained as much as 10 pounds, most of which was from fat, not added muscle."
You can't out walk a calorie-dense diet, and this type of exercise tends to increase appetite without having much of a positive effect on overall metabolism. In addition, people often think "Well I just walked for 30 minutes at a hard pace, now I can treat myself to a Starbucks (or whatever)."
I don't know why any exercise scientist would have had any expectation that endurance activity would increase muscle mass. It is well known and taught in Exercise Science 101 that muscle hypertrophy occurs only in response to low duration efforts requiring high force production, i.e. resistance training, whereas endurance activity causes overuse atrophy. This is why endurance athletes look like they barely survived starvation.
If you want your body to have a low body fat percentage and the pleasing appearance that comes from well developed muscles, you need to do resistance and sprint training, not LSD. This woman gained muscle, lost fat, and transformed her physique with brief, infrequent, hard resistance training and not a moment of cardio.