That said, adjustment #1 was to stop eating so much sweets and stop eating out of boredom. I'm accomplishing that with the No S Diet, which provides simple rules: no snacks, no sweets, no seconds, except on days that start with s and special occasions. I was always bad for keeping snack food around the house and munching on it at the computer, and this approach takes care of that nicely, but I still get to treat myself occasionally.
It's only been one and a half weeks and I'm noticing a shift in my approach to food already -- while I've always appreciated good food, I'm appreciating boring food way less. The level of self-disappointment is a lot higher than the value of the snack for pretty much everything I used to munch on, so willpower is winning out.
I've been keeping a 1L bottle of water at my desk lately too, to keep my water intake up. Getting through a litre a day is easy.
I've been dragging myself to the gym at work too. For now I've been getting in two 30-minute cardio sessions on machines aiming at maintaining 75% of my maximum heart rate. As of the last session I pushed that up to 45 minutes, and I plan on getting three sessions per week this week and from now on. Much later I'll start adding in resistance training -- before, I found that resistance training made me want to avoid the gym, so I'm getting the psychological side of things taken care of first.
Anyhow, the end result of all of this is that lately I feel great without feeling like I'm doing anything particularly weird, which I think is what will make this all sustainable. To keep track of what I'm doing, I created reductionism, which is going to be my detailed food and exercise journal; you're welcome to watch or check back occasionally if you're interested, but I imagine it'll be pretty boring if you're not me.
(Also, please avoid using comments here to advocate a particular diet regimen; I don't want that discussion here.)