What you eat definitely affects you in every way.  Think of your food as the building blocks of your body, if the bricks are of a poor quality, your building, or body, will be frail and susceptible to environmental stress.  Try eating healthy as much as possible.  Also chemicals in the food supply can be aggravating for lupus (for example, aspartame has been proven in many studies to be a trigger for lupus symptoms), so I recommend organic food as much as possible, never getting to the point where what you eat is a source of stress.  Stress is worse for lupus than junk food!
   Also be aware of food allergies, if you suspect you may have any, the easiest method is going into a bland diet (based on white rice) for 1 to 3 days, and then start adding the foods you suspect one every 2 to 3 days.  If you feel sick after any particular food, it is very possible you are having a reaction to it and should eliminate it from your diet.  
   The most allergenic foods are: strawberries, eggs, chocolate, coffee, gluten (bread, beer, pasta,etc) and lactose (milk derivatives).  If you eat any of these and feel fine, continue to eat it, if sick, stop.  You can be allergic to any food, so watch yourself closely, see what effect particular foods cause you and modify your behavior accordingly.
   There is no diet for everyone, so you should make your own best diet based on how different options make you feel.  At the end your body is different from everyone else’s and you are the best judge of what is good for you.
Taken from the book: Befriending the Wolf: The Guide to Living and Thriving with Lupus, soon available in it’s electronic format.