It's easy! Keep one's mouth (almost) shut.
Some years ago, realising that my clothes had all shrunk in the wash and M and S sizes had dumbed down, I began a 'regime'. Not being a 'joiner' (a gym or slimming club just isn't for me), I went alone.
I ate everything I wanted to but less of it. Lo and behold, in eighteen months, I had lost 4.75 stones.
Then... I fell and broke my left leg and right foot and was unable to be weight-bearing, so 'he who should be obeyed - when I had no choice', stepped in and..... I put almost three stones back on. It's unfair to entirely blame him but his idea of a portion is not the same as mine and once on the wrong track, I just let go.
So, once again I have taken the plunge and am jogging along nicely on just... eating less. The weight loss is between one and two pounds a week but it is every week.
I am not a martyr, having a piece of dark chocolate each evening and on a sunny weekend, a Magnum ice cream but by eating less and less often, it is easy peasy and can be done