During November, National Novel Writing Month (NaNo), my waistline expanded two and then nearly three inches above normal, and I was uncomfortable and not happy. I wasn't eating more or exercising less. The rest of me didn't fatten. Just my waistline.
I was, however, drinking extra coffee, always black, usually a cup at about 4 p.m., to get eight more hours out of my day and energy to write more. The NaNo write-ins were held at coffee shops and I drank it there it when I normally didn't. My waistbands got tighter. I switched to elastic waistbands. Tighter and tighter. I exercised more. Weight was going up a half-pound every five days. I couldn't imagine what I was doing to encourage it.
My waistline hadn't been so big since, years ago, I was depressed and drank coffee in the morning to drag myself to work, and had a cup after work to try to pretend I was starting each day over again. When I felt better and didn't take that p.m. coffee boost, the extra pounds fell off. They just fell off.
Coffee gives you its lift by igniting your adrenal glands and producing cortisol, the stress hormone. You have heard that cortisol, if it isn't used for "fight-or-flight," creates visceral fat which is stored behind the stomach muscles, enlarging the waist. The constant coffee drinkers I know have significant bellies. ("Drinking four or five cups of coffee, for example, can cause changes in blood pressure and stress hormone levels similar to those produced by chronic stress" - NYT). From what I read, it's the afternoon coffee that's the most fattening. If you're already stressed and drinking coffee, it's a double whammy. Also, with aging, the body processes cortisol less efficiently. I will give you some links that helped convince me: Here, Here, and Here.
Coffee drinking has its benefits, and I love it, but as an experiment, in the third week of November I quit coffee. Within two days my waistline was down an inch.
This all sounds weird, even to me. We all know black coffee has no calories. Some say the stressor is not the caffeine but other substances in coffee. I might be particularly sensitive to coffee. I can't prove anything; I know only that coffee gives me a big middle. I am passing on this story in case it can help anyone.