If you're on a low-carb diet or you're diabetic, you may sometimes notice a funny taste in your mouth when your blood sugar, also known as blood glucose, is low. It isn't bad breath from poor oral hygiene -- it's a result of your body not being able to burn carbohydrates for energy and burning fat instead.
Carbohydrates and Glucose
When you consume carbohydrates in things like breads, pasta, fruit and sweets, your body converts them to glucose, a type of sugar. Your body then burns the glucose to create energy. Simple carbohydrates such as fruits, refined sugar and white rice are converted to energy quickly and are used up just as quickly. Complex carbohydrates like whole grains give you longer-lasting energy and leave you feeling full longer. You should try to consume more complex than simple carbohydrates.
Your body needs a steady diet of carbohydrates because it doesn't store them like it does fat. If you haven't consumed enough carbohydrates to keep your blood glucose up, that's known as having low blood sugar or hypoclycemia. When that happens, your body begins burning fat for energy.
When your body burns fat for energy, the fat breaks down and creates chemicals called ketones. This is called ketosis. A byproduct of ketones is a chemical called acetone. Your body gets rid of the acetone in your body by breathing it out, which is why you may have a funny taste in your mouth. Your breath may smell funny to others when you're experiencing ketosis as well. Some people describe the taste and smell as a fruity or sweet taste, while others say it tastes metallic.
Who Experiences Ketosis
People with diabetes who experience a drop in blood glucose and insulin often experience ketosis; in this case it's known as diabetic ketoacidosis. If you are experiencing diabetic ketosis it's important to eat or take a glucose tablet as soon as possible and call your doctor or an ambulance if your condition doesn't improve. People who are following a weight loss diet low in carbohydrates and high in protein also frequently experience ketosis as their bodies burn off the fat they're trying to lose. Ketosis may be seen as a sign that the diet is working because fat is clearly being burned off. People with anorexia may also experience ketosis because their bodies are starving. This is known as starvation ketosis.
Other symptoms of low blood sugar include dizziness, headache, extreme hunger, moodiness, shakiness and sweating.