Fruit is an essential component of a nutritious, healthy
eating plan. Fruit provides fiber to slow the release of
fructose and other sugars which prevents a rapid increase of
insulin, followed by an equally rapid crash, the kind caused
by candy bar sugars. Fruit's sugar-fiber combination can ease
hunger pangs as well. Fruits also provide readily accessible
stores of micronutrients -- vitamins and minerals that help
support the body's metabolics often in crucial ways, from
bone and joint integrity to scavenging for radicals to immune-
system support.
In the interest of long-term health the eating guidelines
urge that the average person consume up to 5 portions of
fruit daily.
But what about the more specific energy requirements of the
active person? Will fruit eaten immediately after a period of
intense activity replenish depleted glycogen stores and put
you on the road to recovery?
When it comes to fruit and its relationship to
performance/energy enhancement -- that's, whether it'll help
you do some intense physical activity or get through a long
day with concentration and energy to learn -- you might do
well to understand the relationship between a fruit's
fructose and glucose levels, as each of these sugars affects
the body somewhat differently.
Glucose, derived from complex and simple carbohydrates, is
the preferred fuel source for the brain and the immune system
and for muscles working at high intensities. After you've
ingested a carbohydrate, the glucose that's not immediately
utilized is stored as glycogen in muscle and liver tissues.
When a sudden burst of energy is needed, the body responds by
tapping into these glycogen stores to give you the additional
jolt you need to complete the task at hand.
But all simple carbs are not the same. For energy purposes,
the body prefers glucose to fructose particularly after
exercise when glycogen stores need to be replenished quickly.
After the needs of the muscles have been met, the remaining
glucose is stored in the liver as glycogen for availability
in the future. Only after both the muscle and liver stores
take their fill does glucose end up in alternate storage
sites -- your fat tissues, for example -- where it gets
converted into triglycerides.
With fructose, the simple sugar found in fruits and certain
vegetables, your body behaves differently. Whenever it senses
fructose circulating in the bloodstream, your body imposes
various metabolic antics to send it to the liver for
processing. And the fact is, your liver loves fructose, much
more so than muscle tissue does.
Remember, the body constantly monitors your glucose needs
instructing the liver to release a payload sufficient to meet
your body's energy demands -- whether for training or
recuperation. Adding fructose to the body can halt this
monitoring process so that the liver can turn its attention
toward processing fructose, which demands more intricate
conversion than glucose. And this is where scientists part
company.
One group notes that during this conversion process, some
fructose may escape liver metabolism and when this happens,
the fructose may provide some energy but much of it goes
right to your fat stores. This excess fructose can also
result in increased production of fatty acids, cholesterol
and low-density lipo-proteins, the bad seed of the
cholesterol equation. Finally, fructose can also lead to
gastric irritability depending on the amount you've
ingested.
The opposing group of sport scientists agrees with the claims
of the proceeding group but stresses that they overstate the
case when applied to the real world. This second group notes
that most research in this area uses a pure form of fructose
given in massive dosages that do not convert to real-world
amounts. For example, to approximate the typical 50gm dose of
crystalline fructose in a research lab, you'd have to eat
roughly 14 oz. of apple (7.3 gm of fructose per 4 oz. of
fruit) at one sitting or 110 oz. of cantaloupe (1.8 gm per
about 4 oz. of fruit). If this doesn't lead to gastric
distress, you've got an iron stomach.
These scientists also stress that the high-fiber content of
fruit actually slows down the release of fructose into the
system, making its impact on the liver less stressful; the
crystalline type of fructose, on the other hand, moves into
your body as if it were on a deserted freeway. And they point
out that the digestive system of man was apparently designed
primarily to process fruits and nuts.
Don't ignore the benefit of fruits in your overall diet.
Fruits are a potent source of various phytochemicals and
antioxidants that help scavenge the free radicals that result
from the training/workouts. Fruits can be excellent sources
of fluid so don't be afraid to use them for hydration
particularly lower-fructose types like watermelon.
