Maybe there is a relationship between sugar consumption and our ability to cope with stress? I found, that when I stopped eating sugar, it wasn't exactly a big revelation, but merely a subtle change (mentally), that made me somehow less anxious and when I had irrational anxiety "attacks", I was able to suppress them better.

I don't have any better way to explain this psychological stuff, but for me there was a change for sure. A subtle one, but it made a big impact on my life long term.

The reason I stopped eating sugar was that I saw a pattern in my moods depending on what I ate. I initially thought that it my eating habits were dictated by life circumstances and that life circumstance were dictating my mood, but two things stood out, which left me to try going without sugar.

First I wanted to loose weight, so I went on a protein only diet during a very stressful time and it made me feel pretty good. Second, I was feeling even better, when I was fasting. Third, I had my worst "breakdown", when I was training for a marathon (I ran many, so it wasn't marathon stress) and ingested a lot of sugar.