Headaches are one of the most commonly reported side effects of a high-protein/low-carb diet, according to a CBS Healthwatch news story from February 2009. Constipation, rashes, muscle cramps and bad breath are other reported side effects. Headaches might be the result of low blood sugar, called hypoglycemia; or they might be caused by the lack of nutrients from a diet low in fruits, vegetables and whole grains.
Hypoglycemia and Headaches
Headaches are often the first sign of low blood sugar. Your brain needs glucose to function; the rest of your body prefers glucose, but can use other sources of energy. When there is a rapid drop in blood sugar, blood vessels in your brain constrict, raising blood pressure in your head and causing a headache. When your glucose levels drop, your body releases hormones to signal the release of stored energy. These hormones may also contribute to your headache, according to Dr Grant Shevlin of the Australian Headache and Migraine Information site.
Carbs and Glucose
Fat, protein and carbs can be used for energy, but carbs are easiest and fastest for your body to convert to glucose. Following a low-carb diet limits the available blood sugar -- this is one of the ways a high-protein/low-carb diet helps you lose weight. When you don't have a readily available supply of glucose your body will use stored fat for energy. But converting fat to glucose will release hormones that could contribute to your headache.
Nutrition and Headaches
Dr. Arne Astrup, a Danish obesity expert interviewed by CBS News says the lack of nutrients found in fruits, grains and vegetables cause headaches on a low-carb/high-protein diet. Austrup says that a carbohydrate deficiency hinders brain and muscle function. Astrup notes that you need a minimum of 150 grams of carbohydrates daily, but that some phases of popular low-carb diets restrict carbohydrate intake to between 30 and 100 grams.
Treatment
If your headache is due to a lack of glucose or a lack of nutrients, the best way to treat it is to consume more carbohydrates. If your headache is caused by hypoglycemia, eating 15 g of a simple carbohydrate -- 4 oz. of pure fruit juice or regular soda, 1 tbsp. of honey or 8 oz. of milk -- should provide enough glucose to improve your headache. Ensure proper nutrition for eating complex carbohydrates such as a variety of vegetables, fruits and whole grains. Avoid added sugars and starchy carbohydrates that provide empty calories without essential vitamins or minerals.
References
- CBS News Healthwatch: Low-Carb Side Effects Cited; February 2009
- National Diabetes Information Clearinghouse; Hypoglycemia; October 2008
- Headache.com.au; Blood Sugar Levels; Dr Grant Shevlin
- National Headache Foundation; Hypoglycemia; 2011
- University of Maryland Medical Center; Low-Carb Diets: The Right Way to Go?; April 2007
Member Comments