For most of my life I have been immune to caffeine. The down side was that if I needed to drive all night or get up early, caffeine was useless to me. On the other hand, after a hard day's athletic contest when I was fairly dehydrated and could drink 240 ounces of diet soft drink to rehydrate and not lose a wink of sleep.
All that changed recently.
A couple years ago I lost about fifty to sixty pounds (I lost more, but regained some of it. I've been at my current weight for more than a year or so). In order to stay hydrated (because I don't like the taste of the local water) I drank about ten to eleven liters of diet creme soda a week for the last three years. The manufacturer switched over to a caffeinated version. It didn't bother me until I read Taubes and couldn't bring myself to eat any more sugar or white flour.
Among the other changes that made in my life I became sensitive to caffeine. I could feel it. I didn't like it. I went cold turkey. Luckily for me, the immunity also meant no withdrawal effects at all. I haven't touched creme soda since.
But, recently we did a road trip. We drove late, then because of some problems with hotel rooms, had to drive sixty miles more. A storm warning had us getting up early, an hour earlier than the "early" we had planned on before the extra late stop.
Much to my surprise, four ounces of diet pepsi, spread over twelve hours of driving, kept me alert and awake. But, the next morning I found myself wanting another ounce. I still had eighteen ounces left ...
Dang. I cut myself off immediately, but it was an amazing learning experience. Caffeine had gone from neutral and a non-issue to extremely unpleasant, to useful in measured amounts, to very, very attractive, in less than a week.
Oh, and I'm drinking diet root beer now, and water.
On the Shangri-la Diet I used to eat six slices of bread a day, two cups of yogurt with half a cup of sugar, etc., every day. I now eat only 240 calories or less a day of full grain bread, no sugar and no white flour. I actually have enjoyed the change, though it has been interesting. Has not made much of a difference in my weight. My SLD calories come from three tablespoons of extra light olive oil a day.
When I'm out I tend to get chicken salads. There is always a grilled chicken salad on the menu. Just take the dressing on the side.
My rotator cuffs are getting much, much better, which means I'll be able to restart some sort of serious exercise again, which seems to make a big difference for me. From 245 to 189 or so, it is just SLD. From 189 to 167 it is SLD and exercise. I'm still learning to understand my body and how it all works, just grateful it still does.