Why Do I Get a Headache After Eating Carbs?

Eating the wrong kinds of foods can give you a carb headache. To avoid this problem, eat high-fiber complex carbohydrates, such as fruits, vegetables and whole grains, and limit your intake of refined grains and sugary foods.

The Migraine Trust explains how low blood sugar, or hypoglycemia, can lead to migraine or a carb headache. Carbohydrates serve as the body's main source of energy. When you eat carbohydrates, your body transforms them into glucose, which is used as fuel wherever it's needed. Because the brain requires a continuous supply of glucose, it's one of the first organs affected by insufficient glucose levels.

Most of the symptoms of hypoglycemia stem from a lack of glucose in the brain. These include headaches, confusion and faintness, says Migraine Trust. Causes can include eating high-sugar foods, skipping meals, fasting or dieting too rigorously. Even delaying a meal can cause glucose levels to dip enough to produce a headache.

Certain dietary practices can reduce the frequency of sugar headaches or headaches triggered by hypoglycemia. These include avoiding skipping breakfast or meals and eating small, frequent meals.

In addition, improving the quality of the diet can help avoid a carb headache. Migraine Trust advises adopting an eating plan that is rich in fruits, vegetables and unrefined foods while low in sugary foods and refined grains such as ice cream, cake and cookies. Naturally occurring sugars in unrefined foods like fruits are digested more slowly than foods high in processed sugar, so they're not as likely to trigger the overproduction of insulin that results in hypoglycemia.

Just as headaches are a symptom of hypoglycemia, they're also a sign of hyperglycemia, which is high blood sugar. When you eat carbohydrates, such as bread and pasta, glucose is absorbed into the bloodstream, but, as the Mayo Clinic notes, it can't enter the cells without the aid of insulin. People with diabetes either have a lack of insulin or their body is resistant to its effects. Consequently, glucose levels rise in the bloodstream, producing hyperglycemia.

Headaches, increased thirst and frequent urination are some of the early symptoms of hyperglycemia. Mayo Clinic advocates following a diet that helps keep diabetes and hyperglycemia under control. It features nutrient-dense complex carbohydrates that include fruits, vegetables, whole grains, beans and peas. The diet also involves low-fat dairy products, heart-healthy fish and sources of healthy fats such as olive oil and nuts.

Read more: How to Detox From Gluten

MedlinePlus describes celiac disease as an immune disorder that is caused by an intolerance to gluten. This protein, found in wheat, barley, rye and a host of products, harms the small intestine, which results in symptoms that can involve the digestive tract or other parts of the body.

While a third of adult sufferers experience diarrhea, this age group is more likely to manifest wide-ranging symptoms. These include fatigue, arthritis, depression, osteoporosis, seizures, infertility, itchy skin rash, canker sores in the mouth, liver disorders and pain in the hands and feet. Migraine headaches are another sign.

The National Institute of Diabetes and Digestive and Kidney Diseases notes that the diet for people with celiac disease involves avoiding foods that contain gluten, such as grains, cereals, pastas and many processed food products.

Fruits, vegetables, potatoes, rice, fish and meat are gluten free, so they're included in the eating plan. Quinoa, buckwheat and gluten-free breads and pastas may also be a part of the diet. Many frozen, canned and processed foods contain gluten, so if you have this disease, read labels carefully when shopping.

Like celiac disease, nonceliac gluten sensitivity involves adverse reactions to gluten, states Beyond Celiac. Those with this disorder experience some of the same symptoms manifested in celiac disease, but they don't have the intestinal damage. Common signs include gas, bloating and abdominal pain, as well as constipation and diarrhea. Other frequent symptoms are fatigue; joint pain; nausea; brain fog; and numbness in the fingers, arms or legs. As in celiac disease, headaches are one of the signs.

According to Beyond Celiac, new research indicates that gluten alone may not be responsible for the symptoms. Part of the condition may be a reaction to eating FODMAPs — a group of poorly digested carbohydrates. It should be noted that wheat, rye and barley, which are gluten foods, are also FODMAP foods.

Read more: 5 Reasons Gluten Intolerance Is Skyrocketing

The American College of Allergy, Asthma & Immunology defines a wheat allergy as a condition that occurs when the immune system becomes sensitized and overreacts to wheat. People with a family history of allergies, eczema or asthma have a higher likelihood of developing an allergy to a food.

Symptoms of a wheat allergy include nausea, diarrhea, stomach cramps, hives, sneezing, runny nose and asthma, states the American College of Allergy, Asthma and Immunology. As in celiac disease and gluten sensitivity, headaches are one of the signs. Although less common, anaphylaxis, a life-threatening reaction that can lead to shock, may occur.

To prevent a reaction, if you have this disorder, you should avoid wheat. However, as noted by Food Allergy Research and Education, you can eat a wide variety of other grains, including oats, rye, corn, barley, rice, quinoa and amaranth. In baking, wheat-free flours are safe to use. Wheat can be present in many products, such as soy sauce, baking mixes and ice cream, so it's important to read labels when shopping.

If you get a headache after eating bread or pasta, especially if you experience some of the other symptoms from any of the three wheat-related disorders, correct diagnosis is the key, says the Gluten Intolerance Group. Once you receive a diagnosis, you can follow the appropriate diet.

The Gluten Intolerance Group states that celiac disease diagnosis is based on blood screening and a small intestinal biopsy. Doctors identify gluten sensitivity by ruling out other causes of the symptoms and then testing to see if removing gluten from the diet improves the condition. An allergist can diagnose a wheat allergy with an allergy test.