Diabetes Health board member Sheri Colberg, PhD, has published a completely revised, updated, and expanded version of her 2001 book, Diabetic Athlete’s Handbook: Your Guide to Peak Performance. Dr. Colberg, a diabetic athlete herself, has a PhD in exercise physiology. Her book draws upon the experiences of hundreds of athletes with diabetes to provide the best advice for exercisers with diabetes, either type 1 or type 2.
Diabetic Athlete’s Handbook has detailed advice on blood sugar regulation, medications, nutrition and supplements, injury prevention and treatment, and mental strategies for maximizing performance and optimizing health, along with detailed regimen advice for more than 100 sports and activities.
Specific insulin advice is included for pump users and those on a basal/bolus insulin regimen (including Lantus, Levemir, Humalog, NovoLog/NovoRapid, and Apidra). The book also has examples from hundreds of athletes with type 1 and type 2 diabetes, along with 10 profiles of elite and amateur athletes, from professional surfers to Iditarod dog mushers.
It is a “must have” for the athlete in your life.
Sheri Colberg, PhD, also known as Sheri Colberg-Ochs, is an author, exercise physiologist, and associate professor of exercise science at Old Dominion University in Norfolk, Virginia. She was also appointed as adjunct associate professor of internal medicine at Eastern Virginia Medical School, also in Norfolk.
The following is an excerpt from Chapter 4 of Dr. Colberg’s book: “Diet and Supplements for Active People.”
As a physically active person, you are likely to be bombarded with claims about the superiority of particular diets and guarantees that specific nutritional supplements will enhance your athletic performance. With the fierce competition that exists in sports nowadays, athletes look for any edge to improve their athletic ability. They will try almost any supplement or technique to get it-amino acid supplements, glycerol, sports drinks, creatine, carbohydrate loading, and ginseng, to name just a few. In reality, few of these advertised ergogenic aids (i.e., anything that enhances performance) for athletes are scientifically proved to enhance your physical prowess. Moreover, as an athlete with diabetes, you may have special concerns about the effects of various diets and supplements on your diabetes control, as well as how and what to consume to maintain your blood sugars during exercise.
Effective Dietary Practices of Active People
The first thing you should know is that active people can eat in more than one way and perform effectively in sport and that the best way may be slightly different for everyone. The diets of diabetic athletes are as varied as the sports and activities that they do. No one likes to have to stop exercising because of low blood sugars, though, so preventing hypoglycemia during and after any activity is a high priority for everyone. Becoming low unexpectedly can be especially inconvenient if you’re out for a run or a long bike ride and are still a good distance from your destination. Prevention has a lot to do with your food intake both before and during the activity. In general, rapidly absorbed carbohydrate is most effective to take during exercise, but protein and fat can be helpful in preventing lows as well. The following sections include some basic points to remember about the different classes of foods, along with a discussion of nutritional supplements.
Carbohydrate: Critical to Make It to the Finish Line
Carbohydrate is the most important energy source for all types of exercise. Muscle glycogen (the main storage form of carbohydrate) is the primary source of energy for the lactic acid system, along with being the main fuel for moderate and intense aerobic exercise. Whenever you eat carbohydrate, it is broken down by enzymes in your digestive tract, absorbed through the wall of your small intestine, and released as glucose into your blood, making it the main simple sugar found there. Your muscles can take up and use carbohydrate, but they generally use more of the glycogen already stored in them, as long as it’s available.
The more intensely you exercise, the greater the rate of muscle glycogen depletion in the muscle fibers that you’re using. Your liver also releases its more limited glycogen stores as glucose into the bloodstream to try to maintain your levels during exercise. Glycogen is critical to most activities, so if you deplete your muscle and liver stores during exercise, you will become fatigued and either have to stop exercising or slow down considerably. You’ve heard of athletes “hitting the wall,” often around the 20-mile (32-kilometer) mark of a marathon; they’ve usually just run out of glycogen at that point. Fat “burns” in a carbohydrate flame, so you can’t even use fat effectively as an alternative fuel after you’ve depleted your carbohydrate (glycogen and glucose) stores.
In general, most exercisers (even those without diabetes) need to take in some carbohydrate before and during prolonged exercise to help maintain their blood glucose levels, although consuming it usually doesn’t slow down the body’s use of glycogen, which is primarily driven by the intensity of the workout. Any carbohydrate that you take in during exercise is rapidly metabolized and begins to be available for your body to use within about five minutes. The type of carbohydrate that you need to consume depends on factors such as how long you’ll be exercising, the intensity of your workout, and what your blood sugar and insulin levels are before and during the activity, as you will see in the sport-specific examples offered in part II.
Supplementing With Carbohydrate Before, During, and After Exercise
Carbohydrate supplementation is an effective performance enhancer whether or not you have diabetes. In general, taking in extra carbohydrate is not usually necessary for events lasting an hour or less, if you start with normal muscle and liver glycogen stores and moderately low levels of insulin. But you may need to take in carbohydrate for exercise lasting less than an hour, depending on how much insulin is in your system and whether your blood glucose is likely to drop during the event. If you’re running low on glycogen for any reason or your insulin levels are too high, your muscles will use more of your blood glucose than normal, and you’ll likely have to supplement then as well.
If you train on a regular basis, you will need to take in enough carbohydrate every day to restore your muscle and liver glycogen levels between workouts. When you have diabetes, you have to be especially careful to keep your blood sugars in control before and after exercise so that your glycogen repletion takes place normally. Your body needs adequate insulin levels, especially more than an hour after exercise when glucose uptake into your cells becomes more dependent on insulin. Taking in some carbohydrate immediately after you finish a workout or race will speed up your initial glycogen replacement and help lower your risk of developing low blood sugars later, all with minimal need for insulin during that period. Carbohydrate intake also helps ensure that your glycogen stores are maximally loaded by the time your next workout rolls around. Keep in mind, though, that glycogen repletion can take 24 to 48 hours, and you need to control your blood sugars well during that time for maximal carbohydrate replacement. If you eat a low-carbohydrate diet, full restoration of glycogen will take longer; you may want to consider taking in more carbohydrate of any GI than your normal during that time (at least 100 grams per day) and taking enough insulin (if you use it) to facilitate the storage of carbohydrate as glycogen in your muscles and liver. The time when your body restores glycogen most rapidly is during the first 30 to 120 minutes after exercise. If you want to minimize your risk of later-onset lows, take in some carbohydrate and keep your blood sugars under control during this time to optimize its repletion.
Fluids, Sport Drinks, Gels, and More
Gatorade, PowerAde, All-Sport, Cytomax, GatorLode, Ultra Fuel, GlucoBurst gels, Power Bars, Clif Bars-with so many sport drinks, gels, and other sport-related supplements to choose from, how can you choose which one to use, if any? Let’s start by taking a closer look at sports drinks and other fluids. During exercise, a fluid that is a 5- to 10-percent carbohydrate solution (meaning that it contains 5 to 10 grams of carbohydrate per 100 milliliters of fluid) will empty from your stomach as rapidly as plain water does, can hydrate you effectively, and will provide you with carbohydrate. If you’re worrying about maintaining your blood sugars more than your hydration, choose one with a slightly higher carbohydrate content; not surprisingly, taking in a 10-percent carbohydrate sports drink has been shown to keep blood sugars higher than consuming a similar quantity of an 8-percent one.
You should use more concentrated solutions (above 10 percent) only before or after exercise because their emptying from your stomach is somewhat delayed. Fruit juices are usually more concentrated than 10 percent and should be diluted for faster absorption during exercise, but remember that their GI is usually lower than many other choices. You may also want to avoid juice for another reason: Drinks with high amounts of fructose (fruit sugar) may cause abdominal cramps or diarrhea, likely because fructose is absorbed more slowly than glucose is and it pulls water into your stomach and small intestines when consumed in high concentrations.
Read Part 2 which includes a different chapter excerpt from Colberg’s book