I have a friend in the 80’s who for years have been eating using food banks, a lot of prepared/microwaveable meals. Recently a change of circumstance resulted in him moving into a place where food is all made from scratch, often organic. A lot of his lab tests went from concerning to healthy over 6 months. He does not have CFS, but this does illustrate that diet can have a very major impact. I know that many CFSers survive on food banks in various countries around the world.
Often, one of compounding problems is that a CFS patient is so tired, that all they can do is put a package into the microwave (which can reduce the vitamin and other good content by 50%). Even boiling vegetables in soft water, strips remove nutrients. Overcooked, does the same.
One of the irony that I see is that people will spend money on Inulin capsules, instead of using natural sources (and often bringing other minerals and vitamins with it), for example: Banana, Garlic, Chicory root, Globe artichoke, Jerusalem artichole, Jicama, Onion, wild yam [wiki]
I have posted individually in the past and will attempt to reduce this to a simple reference page without citation (see links below for citations)
What is my daily diet?
I do not keep religiously to it, but this is my ideal pattern
- Breakfast: Either rye bread with butter/ cheese/ and eggs OR porridge with bran added (Not pasturized milk or goat milk)
- Lunch: Crisp break or rye bread with cheese, a banana or other fruit
- Supper: 4 oz of fish or meat, salad (I like Kale) with nuts, one or two of the greens above
- Snacks: Mixed Nuts
- “Compared with milk intake, cheese consumption significantly reduced urinary citrate, creatine, and creatinine levels and significantly increased the microbiota-related metabolites butyrate, hippurate, and malonate.” 
- How do I get there from here!!!???!! — Part Two
- Sorbitol / Glucitol
- Diet Impact on Microbiome
- E.Coli and Green Vegetables
- Migraines, diet and the microbiome
- Roundup and food grown with Roundup
- Peanuts – A recommend part of diet
- Wikipedia FODDMAR list is in the right general direction but their target is different and their reported results to date has been less than ideal.