Your brain uses glucose as its primary source of energy as well as oxygen. Glucose must be provided through your bloodstream by the food that you eat, since brain neurons cannot store it and need almost twice as much fuel as the rest of the cells in your body. Lactate is another source of energy for the brain.
Glycemic Index of Carbohydrates
According to the article "Carbohydrates: Good Carbs Guide the Way," published by the Harvard University School of Public Health, carbohydrates' glycemix index classification depends on how quickly they release sugar into the bloodstream. The faster the carbohydrates release sugar, the higher the glycemic index and the less useful they are as a source of energy for your brain.
Simple carbohydrates have a higher glycemic index, since they have a single strand sugar molecule. Complex carbohydrates typically score lower than a 55 glycemic index, since they have longer sugar-molecule chains that release glucose slowly into the bloodstream. Examples of complex carbohydrates include oats, lettuce and beans.
Oxygen
According to Dr. Peter Zeischegg in his article "Oxygen - The 'Missing Link'," your brain uses up to 20 percent of the oxygen you breathe. Dr. Zeischegg explains that brain neurons use both oxygen and glucose to produce adenosine triphosphate, or ATP, which fuels all cell functions.
Exercise is the primary way to increase your oxygen intake. As you increase your heart rate through cardiovascular workout, your lungs open and you breathe in more oxygen that your brain immediately converts into energy. Exercise also stimulates your digestive system and increases your appetite. This will make you want to consume more food, and if you choose the right types of carbohydrates, you will be providing additional glucose for your brain to use as energy. Meditation also can increase your oxygen intake as it focuses on breathing deeply.
Lactate
According to the article: "Alternative Energy Source Found For Your Brain," published by the website Live Science in 2008, muscles produce lactate during physically demanding exercise, which the brain can use as an alternative source of energy. This is a response from your brain to leave any glucose for your muscles to use as energy during the exercise.
