What you have to remember is that this is written FOR the DM.
They like to, should we say, slightly exaggerate things.
Yes, it will be her own words mainly, but she will have been asked I think to put a certain emphasis on parts of it.
Having said that, I think there is nothing wrong in watching what you eat most of the time, especially when you are older when weight goes on much more easily.
Also- maybe it's a bit of a misnomer to think that when you get to X age you should have your mind on other things and not be bothered about your appearance so much. It's slightly ageist or even patronising to say "There there dearie, get back to your garden and forget about your looks", when someone is 70, or 75, or 80.
But above all, don't forget that MS was PAID a lot of money to write this feature. She would have been asked to lay it on with a trowel- the DM likes to provoke its readers. Half measures- such as saying I eat carefully all year then have a blow out at Christmas -would not get the readers going half so much, would it?