Over the last two years I've lost fifteen kilos. I was just on the borderline between overweight and obese, and I'm now told that my body fat is just hovering on the low limit of what's healthy for a 38 year old.
I did this without ever going hungry, or following any strict rules, or increasing the amount of exercise I did.
Rather more importantly, my personality has changed. It seems strange to write it now, but from adolescence until two years ago, I'd always assumed that I'd commit suicide. This was not in fact as bad as it sounds. It meant there was no bar to riding a motorbike, I've never felt guilty or unhappy about smoking cigars (which I love), I never felt the need to get a pension, or buy in to the British housing bubble when despite everything I know about the behaviour of markets the peer pressure was incredible.
But the reason I'd assumed it was not so good. Despite a generally sunny personality, every so often I'd be seized by a terrible fit of depression. In this state I felt that everything was going wrong, my life was a waste, my friends despised me. I called it the black dog, and when it was sitting on me I had got into the habit of hiding. It was not a mood to inflict on friends.
Usually this only lasted a couple of days. If I noticed what was going on I could cure it with intense exercise. But usually I didn't realise what was happening until the mood was already lifting. I pinned a note to the fridge 'If everything is going wrong do an ergo! It will help.'.
At one point in my early twenties, when everything really was going wrong, the black dog had sat for several months. And when it was sitting I could do nothing to change the things that needed changing, because every scheme, every ray of hope was dismissed out of hand as dreadful, too much trouble. Some days I didn't get out of bed because I could see no reason to.
I had assumed that the periodic mood swings were part of my personality. I'd seen enough evidence of similar behaviour in others to not find it suspicious. And although in hindsight the bout of depression in my twenties had probably needed treatment, the little swings I got every month or so just struck me as part of normal life.
I haven't had a trace of the black dog now for two years. And it happened because I got bored of my favourite sport.