You (and the study) are treating exercise as if it is some homogenous substance, and the intensity and type of exercise had no effect on the outcome. To quote the study:
"the so-called active co-twin of the twin pair was physically active
Q2 times per week, and the so-called inactive co-twin of the
same pair, e2 times per month (inclusion criterion 1 is shown
in Fig. 1). If this criterion was not met, the physically active cotwin
needed to participate in leisure time physical activity Q2
times per week at an intensity equivalent to easy or brisk running"
No-one who is serious about training would expect any body composition changes from an easy run twice a week, except at the very lowest levels.
As others have said, "you can't out run your fork". If fat reduction is your goal, you have to get your diet in order. This is generally accepted within the fitness community, and it's a straightforward consequence that is trivial to consume more calories than you expend unless you're, say, trekking in the Arctic. If you want to increase your lean mass you'd better be doing resistance exercise twice a week at a minimum and more like three or four times as your training level increases.
> No-one who is serious about training would expect any body composition changes from an easy run twice a week, except at the very lowest levels.
What's wrong with that as a minimum cutoff level?
And if that's how people actually exercise, then the inefficacy is important to know. This reminds me of the arguments that 'communism has not failed, it's never been tried!' (Real exercise has not failed, it's never been tried by these twins...)
"the so-called active co-twin of the twin pair was physically active Q2 times per week, and the so-called inactive co-twin of the same pair, e2 times per month (inclusion criterion 1 is shown in Fig. 1). If this criterion was not met, the physically active cotwin needed to participate in leisure time physical activity Q2 times per week at an intensity equivalent to easy or brisk running"
No-one who is serious about training would expect any body composition changes from an easy run twice a week, except at the very lowest levels.
As others have said, "you can't out run your fork". If fat reduction is your goal, you have to get your diet in order. This is generally accepted within the fitness community, and it's a straightforward consequence that is trivial to consume more calories than you expend unless you're, say, trekking in the Arctic. If you want to increase your lean mass you'd better be doing resistance exercise twice a week at a minimum and more like three or four times as your training level increases.