Fibromyalgia affects 5 million adults in the United States, according to the National Institute of Arthritis and Musculoskelatal and Skin Disease, and yet the cause is unknown. Management of the disorder that causes chronic pain and fatigue revolves around symptom relief and includes medication, regular sleep, exercise and eating well. While there is no special diet for people with fibromyalgia, there is some evidence that eating certain foods -- or rather avoiding certain foods -- may help.

Start With Healthy Foods

To help manage your fibromyalgia, the University of Maryland Medical Center suggests you eat a variety of healthy foods. This includes antioxidant-rich fruits and vegetables such as blueberries, cherries, spinach and bell peppers. Additionally, instead of refined grains such as white bread, eat more whole grains such as brown rice, whole-wheat bread and whole-grain cereals to increase your intake of fiber and nutrients. Healthy proteins for fibromyalgia include lean meats, cold-water fish, soy and beans. You should also avoid processed foods that offer very little nutritional value such as cakes, cookies, fried foods and soda.

Watch Calories if You Need to Lose Weight

Carrying around excess weight may increase fibromyalgia symptoms, according to a 2014 study published in "Rheumatology International." The researchers suggested a weight-loss diet to help improve symptoms in those who are overweight or obese. The calories you need to get to a healthy weight depend on a number of factors, including current weight, height, gender and activity level. Your doctor can help you determine your calories to lose weight. You can start by tracking your current calorie intake with a food diary and then subtract 250 to 500 calories from that number to create a calorie deficit for weight loss.

Try Omitting Gluten

Some people with fibromyalgia also suffer from nonceliac gluten sensitivity, which is a condition that causes behavioral change, bone or joint pain, muscle cramping, chronic fatigue, foggy mind and leg numbness. Diagnosis of nonceliac gluten sensitivity requires an intestinal biopsy. A 2014 study published in "Rheumatolgy International" found that individuals with fibromyalgia and nonceliac gluten sensitivity who eliminated gluten from their diets had a reduction in pain and were able to return to their normal lives. A gluten-free diet requires the elimination of all foods that contain wheat, rye and barley. While this is promising for those suffering from fibromyalgia, the authors of the study note that the findings are very preliminary.

Look into Other Food Allergens

Eliminating food allergens may also help alleviate your symptoms, according to the University of Maryland Medical Center. Potential food allergens include dairy, wheat -- outside of a gluten allergy -- soy and corn, as well as food additives and preservatives. You should discuss food allergies with your doctor before making changes to your diet. An allergist can test for food allergies with a blood test, skin prick test, oral food challenge or an elimination diet.