Since toxins/preservatives/additives seem to interfere with sleep by causing inflammations in the brain, I started to investigate on diets. During my research, I stumbled on benefits of fasting for detoxifying the body, and decided to conduct an experiment. Therefore, I fasted for six days in a row, I was only drinking water and herbal teas, zero calorie intake then (as a first experiment, I did it in a group somehow supervised by someone with a strong fasting experience).
It turned out that the fasting has had a very positive influence on my REM sleep, as represented on the Fig. 1 below. These results could point out that a food intolerance might be the source of my sleep issue, and therefore gave me a new direction to investigate. After some research, I decided to try out the FAILSAFE diet from Sue Dengate (a diet designed to be free of additives, low in salicylates, amines and flavour enhancers). However, this diet is very constraining to implement with my current lifecycle, to be continued then.
My Zeo sleep graphs collected throughout the experiment can be downloaded from this link.
(Update from Sept. 2014: I finally successfully implemented recently the FAILSAFE diet during almost a month, but did not notice any significant improvement on my sleep. I also experimented another fasting during 6.5 days and ended up with the same positive outcomes as the ones described on this page. I am now investigating on potential impairment of my methylation cycle).
Fig. 1: My REM sleep around my fasting period.