Sports Nutrition

Athletes who want a winning edge require optimal nutrition. When you drink enough water and eat a healthy, well-balanced diet, your body can make energy efficiently and this fuels top performances. You are more capable of making the most of your athletic talents by potentially gaining more strength, power and endurance when you train. One needs to base their diet on a variety of factors including age, height- weight ratio, and physical condition; and the type of exercise you are doing. Please make an appointment with Dr. Serné should you want an individualized nutrition assessment.

Hydration

Water is the most important factor in sports nutrition. It makes up about 60 percent of body weight and is involved in almost every bodily process. Your body cannot make or store water, so you must replace what you eliminate (i.e., urine, sweat). Everyone should drink at least two liters (eight cups) of water each day; athletes require more.

The most important factor in hydration is how much you drink at one time; you may quench your thirst but not sufficiently hydrate your tissues if you drink too much at one time. Maximally, you should drink 500 ml of water per hour to ensure you are hydrating your tissues and maximizing water uptake. Drink plenty of fluids before, during and after sports events to stay hydrated and avoid overheating.

When you workout or compete, especially in hot weather, try to closely match the amount of fluid you drink with the amount you lose to sweat. Cool water is the best fluid to keep you hydrated during workouts or events lasting an hour or less. Sports drinks (i.e., 6-10 percent carbohydrates) are useful for longer events. Most of these types of drinks should be diluted approximately 50 percent with water. Drink even if you are not thirsty. Thirst is not a reliable way to tell if you need water. You won’t start feeling thirsty until you have already lost about 2 percent of body weight - enough to hinder performance. Interestingly, if you stop drinking water once your thirst is satisfied, you will get only about half the amount you need. Some tips for staying hydrated:

Drink small amounts of water frequently, rather than large amounts less often.
Drink cold beverages to cool your core body temperature and reduce sweating.
Weigh yourself after working out and drink 2-3 cups of water for every pound lost. Your body weight should be back to normal before the next workout.
Pay attention to the amount and color of your urine. You should excrete a large volume that is nearly colorless. Small amounts or dark colored urine can indicate dehydration.

Fuel sources Eating a balanced diet is another key to sports nutrition. The right combination of fuel (calories) from carbohydrates, proteins and fats gives you energy for optimal performance.

Carbohydrates

The most important fuel source, carbohydrates come in fruits, vegetables, pastas, breads, cereals, rice and other foods, and should provide about 60-70 percent of daily calories. Your body converts sugars and starches in carbohydrates to energy (glucose) or stores it in the liver and muscle tissues (glycogen), giving you endurance and power for high-intensity, short-duration activities, or non-aerobic activity. If your body runs out of carbohydrate fuel during this type of exercise, it will burn fat and protein for energy, causing your performance level to drop. This can happen if you start exercising without much muscle glycogen, exercise heavily for more than an hour without eating more carbohydrates, do repeated high-intensity, short-duration exercises or participate in multiple events or training sessions in a single day. Use a carbohydrate strategy to stay energized and perform at your best:

Eat carbohydrates for at least several days before exercise/competition, so you start with glycogen-loaded muscles.
Eat more carbohydrates during exercise/competition lasting more than an hour to replenish energy and delay fatigue.

Proteins

Proteins are derived from meats, fish, poultry, eggs, beans, nuts, dairy products and other foods.Ideally protein should provide approximately 12-15 percent of total daily caloric intake. Proteins give your body power to build new tissues and fluids, among other vital functions. Your body cannot store extra protein, so it burns it for energy or converts it to fat. The amount of protein an athlete needs depends in part upon level of fitness; exercise type, intensity and duration; total calories; and carbohydrate intake.

Level of fitness: Physically active people need more protein compared with those who don’t exercise. You also need more when you initiate an exercise program.
Exercise type, intensity and duration: Endurance athletes often burn protein for fuel, as do body builders and others doing intense, strength-building activities.
Total calories: Your body burns more protein if you don’t consume enough calories to maintain body weight. This can happen if you eat too little or exercise too much.
Carbohydrate intake: Your body may use protein for energy if you exercise with low levels of muscle glycogen or if you do repeated training sessions without eating more carbohydrates. When you start with enough muscle glycogen, protein supplies about 5 percent of energy. Otherwise it may supply up to 10 percent.

Fats

Saturated fats are found in animals foods (i.e., meats, eggs, milk, cheese, etc.) and unsaturated fats are found in some vegetable products (i.e., corn oil). To simplify, saturated fats are solid and unsaturated fats are liquid. Fats should provide no more than about 20-30 percent of daily calories. Your body requires a small amount of fat for various critical functions and as an alternative energy source to glucose. Eating too much fat is associated with heart disease, high cholesterol, some cancers, and other major health problems. This can often mean that you don’t consume enough carbohydrates. How your body uses fat for energy depends upon the intensity and duration of exercise:

When you rest or exercise at low to moderate intensity, fat is the primary fuel source.
As you increase exercise intensity, your body uses more carbohydrates for fuel.
If your body uses up its glycogen supply and you keep exercising, your body will burn fat for energy, decreasing exercise intensity.

Which is Better - Carbohydrates or Fats for Exercise?

When it comes to eating for exercise there are several things to consider while meal planning. Carbohydrate, fat, and protein all contribute to the fuel supply needed by working muscles, with carbohydrates and protein providing 4 Calories per gram and fat providing 9 Calories per gram. All nutrients get converted to energy in the form of adenosine triphosphate or ATP. However, each nutrient has unique properties that determine how it gets converted to energy.

Carbohydrate is the main nutrient that fuels exercise of a moderate to high intensity; glycogen for anaerobic and glucose for aerobic exercise. Fat can fuel low intensity exercise for long periods of time (aerobic exercise). Proteins are generally used to maintain and repair body tissues, and are not normally used to power muscle activity. Because the body can not easily store ATP (and what is stored gets used up within a few seconds), it is necessary to continually create ATP during exercise. There are three main pathways to convert nutrients to ATP and it is the intensity and duration of the exercise which determines what method gets implemented. The first path only supplies about 10 seconds worth of energy and is used for short bursts of exercise such as a 100 meter sprint. After this, either aerobic or anaerobic metabolism is used to continue to create ATP. Then major difference between aerobic and anaerobic metabolism is the presence of oxygen to create ATP.

Aerobic metabolism requires oxygen to convert nutrients (carbohydrates, fats, and protein) to ATP. Aerobic metabolism is used primarily during endurance activities.

Anaerobic metabolism (glycolysis), creates ATP exclusively from carbohydrates, with lactic acid lactate threshold) and muscle pain, burning and fatigue make it impossible to maintain that intensity. During exercise an athlete will move through these metabolic pathways. As exercise begins, ATP is produced via anaerobic metabolism. With an increase in breathing and heart rate there is more oxygen available and aerobic metabolism begins and continues until VO2Max is reached. If VO2Max it surpassed, the body can not deliver oxygen quickly enough to generate ATP and anaerobic metabolism kicks in again. Since this system is short-lived and lactic acid levels rise, the intensity can not be sustained and the athlete will need to decrease intensity to remove lactic acid build-up. being a by-product. As lactic acid builds up in the muscle it causes physical discomfort and pain that limits performance. Anaerobic metabolism produces energy for short, high-intensity bursts of activity lasting no more than several minutes before the lactic acid build-up reaches a threshold (the

Pre-Game Nutrition

What you eat several days before endurance activities affects performance. Your food the morning of a sports competition can ward off hunger, keep blood sugar levels adequate and aid hydration. Avoid high protein or high fat foods on the day of an event, as these can stress the kidneys and take a long time to digest. Empty your upper bowel by competition time. General guidelines: 1. Eat a meal high in carbohydrates. 2. Eat solid foods 3-4 hours before events and liquids 2-3 hours before. 3. Choose easily digestible foods (i.e., not fried.) 4. Avoid sugary foods/drinks within one hour of event. 5. Drink enough fluids to ensure hydration (i.e., 500ml of water 1-2 hours before exercise, and an additional 250ml within 15-30 minutes of event.) Replenishing fluids lost to sweat is the primary concern during an athletic event. Drink 125ml of water or dilute sports drink every 10-20 minutes throughout competition.

Carbohydrate loading

To avoid running out of carbohydrates for energy, some endurance athletes like tri-athletes, long-distance runners, swimmers, and cyclists load their muscles with glycogen by eating extra carbohydrates in combination with doing depletion exercises several days before an event:

First exercise to exhaustion. Your workout must be identical to the upcoming event to deplete the right muscles.
Then eat a high-carbohydrate diet (70-80 percent carbs, 10-15 percent fat, 10-15 percent protein) and do little or no exercise starting three days before your event.

Muscles loaded with unused glycogen will be available to work for longer periods of time.

Post-Exercise Meal (to replenish muscle glycogen)

All athletes know of the importance of the pre-exercise meal. However, what and when you eat following exercise can be just as important. While the pre-exercise meals can ensure that adequate glycogen stores are available for optimal performance, the post-exercise meal is critical to recovery and improves your ability to train consistently.

What and when to eat after exercise is a common topic among athletes. The general advice has been to focus on high carbohydrate foods in order to replenish depleted muscle glycogen stores. Research has shown that carbohydrate intake within two hours of endurance exercise is essential to building adequate glycogen stores for continued training. Waiting longer than two hours to eat results in 50 percent less glycogen stored in the muscle. The reason for this is that carbohydrate consumption stimulates insulin production, which aids the production of muscle glycogen. However, the effect of carbohydrate on glycogen storage reaches a plateau. More recent research has shown that combining protein with carbohydrate in the two-hours post-exercise, nearly doubles the insulin response, which results in more stored glycogen. The optimal carbohydrate to protein ratio for this effect is four grams of carbohydrate for every one gram of protein. Eating more protein than that however, has a negative impact because it slows rehydration and glycogen replenishment. The study found that athletes who refueled with carbohydrate and protein had 100 percent greater muscle glycogen stores than those who only had carbohydrate. Insulin was also highest in those who consumed the carbohydrate and protein drink.

Protein has other important post-exercise qualities. Protein provides the amino acids necessary to rebuild muscle tissue that is damaged during intense, prolonged exercise. It can also increase the absorption of water from the intestines and improve muscle hydration. The amino acids in protein can also stimulate the immune system, making you more resistant to colds and other infections.

So if you are looking for the best way to refuel your body after long, strenuous endurance exercise, a 4:1 combo of carbohydrate and protein seems to be your best choice. While solid foods can work just as well as a sports drink, a drink may be easier to digest make it easier to get the right ratio and meet the 2-hour window. However, research of the ratio energy drink only yields results in the United States; Accelerade and Powerbar. So, if you prefer energy gels or other non-protein containing sports drinks, simply add 1 Tbsp of protein powder for every 25 grams of carbohydrate to create the 4:1 ratio.