People with lupus often have food allergies and sensitivities. The most obvious culprits are dairy and wheat. Some alternative practitioners even think that gluten sensitivity plays a causal role in autoimmune disease. Therefore, people who have been recently diagnosed with lupus are advised to eliminate these from their diets to test if eliminating improves the quality of their lives.
People with lupus often find that the quality of their lives improves when they avoid nightshades.
http://www.whfoods.com/genpage.php?tname=george&dbid=62
Moreover, people with lupus, like everyone else in the world, should work on making sure to build their diets around nutrient dense whole foods with limits on processed foods and the elimination of added sugars.
Johns Hopkins offers a list of things that people with lupus should avoid.
http://www.hopkinslupus.org/lupus-info/lifestyle-additional-information/avoid/