CONCERNS FOR OPTIMAL PHYSICAL PERFORMANCE
Carbohydrates, in the form of glycogen (a complex sugar),
are the primary fuel source for muscles during short-term, high-intensity
activities. Repetitive, vigorous activity can use up most of the
carbohydrate stores in the exercised muscles.
Carbohydrates are the primary fuel source for muscles during short-term, high-intensity activities.
The body uses fat to help provide energy for extended activities
such as a one-hour run. Initially, the chief fuel burned is carbohydrates,
but as the duration increases, the contribution from fat gradually
For carbohydrate information on more than 6000 food items, visit Carb Counter
The intensity of the exercise also influences whether
fats or carbohydrates are used to provide energy. Very intense
activities use more carbohydrates. Examples include weight training
and intensive sit-up and push-up workouts.
Eating foods rich in carbohydrates helps maintain adequate
muscle-glycogen reserves while sparing amino acids (critical building-blocks
needed for building proteins). At least 50 percent of the calories
in the diet should come from carbohydrates. Individual caloric
requirements vary, depending on body size, sex, age, and training
mission. Foods rich in complex carbohydrates (for example, pasta,
rice, whole wheat bread, potatoes) are the best sources of energy
for active individuals.
Because foods eaten one to three days before an activity provide
part of the fuel for that activity, it is important to eat foods
every day that are rich in complex carbohydrates. It is also important
to avoid simple sugars, such as candy, up to 60 minutes before
exercising, because they can lead to low blood sugar levels during
Exercisers often fail to drink enough water, especially when
training in the heat. Water is an essential nutrient that is critical
to optimal physical performance. It plays an important role in
maintaining normal body temperature. The evaporation of sweat
helps cool the body during exercise. As a result, water lost through
sweating must be replaced or poor performance, and possibly injury,
can result. Sweat consists primarily of water with small quantities
of minerals like sodium. Cool, plain water is the best drink to
use to replace the fluid lost as sweat. One should drink
water before, during, and after exercise to prevent dehydration
and help enhance performance. The table below summarizes recommendations
for fluid intake when exercising.
|Recommendations for Fluid Intake
- Drink cool (40 degrees F) water. This is the best drink to sustain performance. Fluid also comes from juice, soup, milk and other beverages.
- Do not drink coffee, tea, and soft drinks even though they provide fluids. The caffeine in them acts as a diuretic which can increase urine production and fluid loss. Avoid alcohol for the same reason.
- Drink large quantities (20 oz.) of water one or two hours before excercise to promote hyperhydration. This allows time for adequate hydration and urination.
- Drink three to six ounces of fluid every 15 to 30 minutes during exercise.
- Replace fluid sweat losses by monitoring pre- and post-exercise body weights. Drink two cups of fluid for every pound of weight lost.
Sports drinks, which are usually simple carbohydrates (sugars)
and electrolytes dissolved in water, are helpful under certain
circumstances. There is evidence that solutions containing up
to 10 percent carbohydrate will enter the blood fast enough to
deliver additional glucose to the active muscles. This can improve
During prolonged periods of exercise (1.5+ hours) at intensities
over 50 percent
of heart rate reserve, one can benefit from periodically drinking
sports drinks with a concentration of 5 to 10 percent carbohydrate.
During intense training,
these beverages can provide a source of carbohydrate for working
muscles. On the other hand, drinks that exceed levels of 10 percent
carbohydrate, as do regular soda pops and most fruit juices, can
lead to abdominal cramps, nausea, and diarrhea. Therefore, these
drinks should be used with caution during intense endurance training
and other similar activities.
Many people believe that body builders need large quantities
of protein to promote better muscle growth. The primary functions
of protein are to build and repair body tissue and to form enzymes.
Protein is believed to contribute little, if any, to the total
energy requirement of heavy-resistance exercises. The recommended
dietary allowance of protein for adults is 0.8 grams per kilogram
of body weight. Most people meet this level when about 15 percent
of their daily caloric intake comes from protein. During periods
of intense aerobic training, one's need for protein might be somewhat
higher (for example, 1.0 to 1.5 grams per kilogram of body weight
per day). Weight lifters, who have a high proportion of lean body
mass, can easily meet their protein requirement with a well-balanced
diet which has 15 to 20 percent of its calories provided by protein.
Recent research suggests that weight trainers may need no more
protein per kilogram of body weight than average, nonathletic
people. Most Americans routinely consume these levels of protein,
or more. The body converts protein consumed in excess of caloric
needs to fat and stores it in the body.
For information on the protein content for over 6000 food items, visit High Protein Foods