Well, I have never taken on a specific diet to help my anxiety, but I have found that generally eating a well balanced diet does help me stay calmer.
I have specifically heard of B12 and Magnesium being used to help anxiety.
Ha, I can't believe you never eat nuts and seeds. I practically live on them! Nuts and seeds make perfect snacks, but I'll give you a variety of ideas:
1. Make your own trail mix with nuts, dried fruits, seeds, dark chocolate, sesame sticks, cereal....anything you want. You can't go wrong with trail mix.
2. Add nuts to yogurt, cereal, or oatmeal to add some crunch to your breakfast
3. Sprinkle sesame seeds in your stir-fry to give it a nice nutty flavor
4. Smash up pecans (or other nuts) and tortilla chips and use them to make a crust for chicken or fish
5. Grind nuts in a food processor to make delicious nut butters free of any nasty additives like the jarred versions have. Use this nut butter for sandwiches, ants on a log, dip your apples...anything! My favourite is Almond Butter, but peanut butter is always a good classic as well. Cashew butter is really....buttery and a bit too rich for me. Pecan butter is not bad. Sunflower seed butter is a great alternative for people with nut allergies.
I like have nuts on hand to eat between meals if I get a bit hungry.
Basically, try to eat a diet that consists of mostly whole foods like whole fruit, whole vegetables and the like and eat as little processed food as possible. When you do eat processed food, try to eat it well. For example, try to buy cereal that is whole grain and not a lot of added sugar and no fake dyes and such.
Drink mostly water, try to avoid caffeine.
Feel free to PM me if you want. I lived for a number of years in Boulder, Colorado (a major place for Granola Heads) and I learned a LOT about food. I now live in Austin, Texas and it is becoming a foodie place as well!