All this shows is, if you’re a middle aged woman who isn’t already overweight, it takes a moderate amount of exercise to keep the weight off. If you’re already fat, all bets are off. Prob because fat people have a tendency to get fatter; which is why they are fat in the first place?
Read in one of those crazy health magazines that women need to add half an hour a day of exercise for every year over 40 - that means I should be working out about 26 hours a day now.