Peter SS. It s an interesting question. May be your problem is more a coincidence but diet definitely has an impact on thinking, attitude, behaviour etc. I am an Ayurveda doctor. Ayurveda lays much stress on nature of diet i.e. Sattva, Raja, Tama. Broadly first category is denoting serene and sober nature, third one is pessimistic, depression, anger, negative thinking etc. The second one is mix of two with a tinge of action, anger, superiority etc. This category is more on planet today esp in Indian sub continent. There s a huge wisdom behind classification of food items, herbs etc and their method of growing techniques of such food, vegetables, fruits, dairy products etc which finally culminates into different category characters. It s complex but AYURVEDA people understand more by use and practice. So hopefully you understand the basic info. Be happy, don t worry. It s not only diet but other factors too those impact the behaviour. Wish you best.