Your brain is fueled by blood sugar. When the blood sugar level (BSL) is at a good, moderate, normal level, you feel stable and motivated. But if the BSL is lowered or interrupted, the brain starts shutting things down, stimulating negative attitude hormones.
When blood sugar level is maintained throughout the day, you will be more motivated to exercise, add other movement to your life, be mentally active, deal with stress, and solve problems. Just as eating throughout the day keeps metabolism up, the steady infusion of balanced nutrients all day long will maintain stable BSL. This produces a feeling of well-being.
Before a run: You want to have a BSL that is in the normal range. If it is a bit too low you might feel hungry, lethargic, or tired. When you run in this condition, the increased need for energy can result in even lower blood sugar and a miserable run. But if you eat too much sugar, 45 or more minutes before you run, your BSL can rise too high. You’ll feel really good for a short period, but the excess sugar triggers a release of insulin. This reduces BSL to an uncomfortable level. In this state your energy drops, mental focus is foggy, and motivation goes down rapidly.
For best results in raising blood sugar when it is too low (within 30 minutes before a run), a snack should have about 80% of the calories in simple carbohydrate and 20% in protein. This promotes the production of a manageable level of insulin, which is helpful before a run in getting the glycogen into your muscles and ready for use. The product Accelerade has worked best among the thousands of runners I hear from every year. It has the 80%/20% ratio of carb to protein. If you eat an energy bar with the 80/20 ratio, be sure to drink four to six ounces of water with it.
During trail runs: By testing various BSL snacks and planning ahead, you can be prepared for each trail trek. On short runs of about 90 minutes or less, most of my runners have not found it necessary to eat. There are individual issues, but BSL-boosting snacks are generally beneficial on runs of two hours or more. You don’t want to get on the bad side of your BSL. Low levels are a stress on the brain, literally messing with your mind. If you have not eaten for several hours before a trail run, you’ll receive an increase in the number of negative and anxiety hormones, reducing motivation to exercise or to finish the run.
Eating a snack with too many calories of simple carbohydrate can be counterproductive for BSL maintenance. As previously mentioned, when the sugar level gets too high, your body produces insulin, sending BSL lower than before. The tendency is to eat again, which produces excess calories that are converted into fat. But if you don’t eat, you’ll stay hungry and pretty miserable—in no mood to exercise or move around and burn calories or get in your run for the day.
Once it is established which snacks work best to maintain your BSL, most people maintain a stable blood sugar level by eating small meals regularly every two to three hours. It’s best to combine complex carbs with about 20 to 25% of the calories in protein and a small amount of fat (10-20% of the calories of that snack).
Only if your blood sugar is low. Most who run in the morning don’t need to eat anything before the start. As already mentioned, if your blood sugar level is low in the afternoon and you have a run scheduled, a snack can help when taken about 30 minutes or less before the run. If you feel that a morning snack will help, the only issue is to avoid consuming so much that you get an upset stomach.
Most exercisers don’t need to worry about eating or drinking during a run until the length exceeds 90 minutes. At this point, there are several options. In this case, my rule of thumb is to take 30 to 40 calories every two miles. Diabetics may need to eat sooner and more often, but this is an individual issue.
The brain’s fuel is blood glucose. If you don’t keep this boosted during a long run, the brain will be deprived and will start shutting things down. Avoid this by trying different snacks and amounts, using the formula that works best for you.
Rule of thumb: 30 to 40 calories about every two miles (20-25 minutes), with 2 to 4 ounces of water (60-120 ml).
GU or Gel products: These come in small packets and are the consistency of honey or thick syrup. The most successful way to take them is to put one to three packets in a small plastic bottle with a pop-top. About every 10-15 minutes, take a small amount with a sip or two of water. The Fitlethic ifitness belt has easy-to-use bottles.
Energy bars: Cut into small pieces. Avoid products with a lot of fiber, fat, or protein.
Candy: Particularly gummy bears or hard candies, such as LifeSavers.
Sugar cubes, LifeSavers, gummy bears: This is the simplest of the BSL booster snacks and the easiest on the stomach for most runners.
Sports drinks: I’ve noticed that a significant percentage of my runners experience nausea when they drink sports drinks during a run, so I recommend water. During heavy periods of training it’s a good idea to have a pitcher of a good electrolyte beverage like Accelerade in the fridge, so you can drink 8 to 16 ounces a day, especially during hot weather. If you are going to be running for more than seven hours, it could be helpful to have two to four ounces of an electrolyte beverage every 30 minutes or so—or use a buffered salt tablet like S!Caps. Try several on different training runs to see which settles best in your digestive tract.
Whenever you have finished a hard or long workout (for you), a recovery snack can help you recover faster. Again, the 80%/20% ratio of simple carbohydrate to protein has been most successful in reloading the muscles. The product that has worked best among the thousands I work with each year is Endurox R4.