Kiwi Girl Health is your free online health resource! We are here to share knowledge in the areas of health and wellness so that you can live a healthier and happier life!
Our focus for the month of June is food for fitness! Visit this site to pick up new pieces of information that will help you build a stronger, leaner, healthier body with the help of food.
Exercise and Carbohydrate Timing
Carbohydrates are the premium fuel for
our muscles. In fact, of the
3 fuels (fat, protein, and carbohydrate) carbohydrates are by far the most
efficient when it comes to the provision of energy for the body. However, when it comes to their
contribution to optimal athletic performance and peak fitness it is vital
to consider the time at which they are consumed. If timing is off, carbohydrate
intake can lead to weight gain and reduced physical performance. If timing is well planned,
carbohydrates can be one of our body’s greatest
assets!
When carbohydrates are consumed they are
broken down to glucose, causing an increase in the sugar levels of our
blood. In response to this
elevation our body releases the hormone insulin, which goes to work to
‘clear’ this glucose. The
uptake of this glucose occurs first in the muscle cells of our body, where
the glucose is converted and stored as glycogen. Unfortunately, we do not have the
ability to store unlimited amounts of glycogen and any excess glucose gets
taken up by the liver and converted to fat!
When we exercise, the glycogen from our
muscles is released so that glucose can be oxidized and broken apart piece
by piece, resulting in the production of ATP - a prime source of energy
for the body!
One major issue related to the
consumption of carbohydrate for exercise is the body’s inability to store
large amounts. There is
no such thing as unlimited glycogen storing. Subsequently, during long bouts of
exercise the body can be forced to tap into reserves of body fat and
protein in order to generate the necessary energy to continue
exercising. This is where it
is important to understand the effect of carbohydrate timing on exercise
performance and/or the attainment of exercise fitness goals.
If the goal is top athletic performance,
the consumption of carbohydrates before and during the workout is of great
benefit. In effect, this can
spare some of the glycogen that your body would have been forced to tap in
to and you can perform at higher intensities for a longer period. For someone aiming to exercise at
a high intensity for a longer duration this becomes an important factor to
take in to consideration. The harder you exercise, the more carbohydrate
used, and intense exercise can result in up to 3 times as much glycogen
use as mild exercise The rate of fat
metabolism is slow compared to the rate of carbohydrate metabolism and
during intense exercise (when the body demands the fast delivery of
energy) fat metabolism cannot provide energy quickly enough and the body
must slow down.
Longer, slower bouts of exercise, where
intensity is mild and performance requirements are not as profound, can
draw on fat as an energy source without the performance detriment. As mentioned before, the use of
fat is beneficial because it helps to spare some of the glycogen stores,
supporting a successful endurance training
session.
So, how can this information be applied
to pre-exercise nutrition?
1) If you are taking part in intense exercise,
consider eating a light carbohydrate meal at least 1.5 hours (preferably
2) before your workout. If
you eat too soon before your workout, insulin will still be working to
clear the blood of glucose and you will actually have a harder time
mobilizing stored fuel.
Lethargy could be the end result – when you are looking for the
opposite! Also, if you eat
too close to exercise the blood supply will be drawn away from your
stomach to your working muscles, and you may experience extreme
indigestion.
Complex carbohydrates, that are low glycemic
are what you need as they
provide a steady stream of energy to the body, and take a longer time to
break down. What is great
about low glycemic foods is the fact that they will prevent any premature
lowering of blood glucose levels before training, which can lead to fatigue.
Complex carbohydrates can take 2 hours to break down, so by the time you
are ready to exercise the fuel will be available for use by the body. Some
good choices include:
§
oatmeal (plain,
non-flavoured)
§
quinoa
§
brown
rice
§
spelt pasta
(remember, al-dente pasta is best because the firmer
the noodle the longer the digestion time)
§
sweet
potato
It is our recommendation that you attempt
to purchase organic varieties of food, for more details on the benefits of
eating organic, watch our for our article next month!
If your timing is off and you need to eat
much closer to your workout, then you might consider eating a piece of
fruit that has a medium GI, such as:
Kiwi Fruit
Mango
Raisins and Sultanas
Or, conversely, consume a fresh fruit drink such as orange
or apple juice, diluted in water.
2) If your goal is to specifically burn fat,
pre-exercise carbohydrate intake is not as necessary, but remember that
fat is not an efficient form of energy supply and your workout will not be
super-charged.
PLUS!!
Though less-strenuous exercise promotes fat oxidation during the
workout, more intense exercise leaves you with a larger EPOC (Excess
Post-exercise Oxygen Consumption).
This represents oxygen consumption above resting level, oxygen that
the body is utilizing to return itself to its pre-exercise state. Put simply, your metabolism is elevated for a longer
period following exercise!
Your body is working hard to get itself back to its normal state,
and this work requires calories for energy. As such, intense exercise can be a
great way to encourage an increase in total caloric expenditure and
therefore weight loss.
3) Supplementation during exercise
can be beneficial to supply ready energy and maintain hydration. Unfortunately, even if you’ve
eaten a good pre-workout carbohydrate meal, muscle glycogen depletion can
and will still occur. If you consume a drink that is part carbohydrate
(and part protein) you will delay the onset of fatigue due to lack of
available glucose.
4) It is important to remember that
the inclusion of protein before and during exercise is critical to the
enhancement of performance and recovery. To find out more about when and
how to include protein click here
Carbohydrate and
post-exercise nutrition
After exercise, the body is affected in a
number of ways. Glycogen is
depleted, stored ATP and other substrates are exhausted, muscles have been
damaged, and the level of blood cortisol has risen causing the body to
break down tissue as opposed to build it up. Such an internal environment will
discourage tissue growth and prevent positive
adaptations to exercise training.
Not what we want!!
Fortunately, the body is designed to
respond to these changes by providing a short post exercise period in
which all these negative effects can be avoided. This is, however, only possible
when proper nutrition is provided.
Muscle glycogen
re-synthesis rates are dramatically elevated during the immediate
post-exercise period, as is the rate of protein synthesis. As such, carbohydrate should be
consumed during the immediate post-exercise period. Similar to re-stocking
empty shelves in a grocery store, our body will re-stock our muscles cells
with a healthy stack of glycogen.
Recovery is enhanced, and depleted energy stores are no longer
so!
What is also great
about consuming carbohydrate during the post-exercise period is that even
in the face of high carbohydrate intake fat loss is still enhanced. Confused? After exercise the body is working
hard to repair muscle damage and replenish energy stores and of course
carbohydrate and protein are recruited for these important tasks. What does this do? It leaves fat as a prime source of
energy supply during this period.
Glucose will be stored as glycogen in our muscles, fat will be
oxidized to provide energy, muscle building will be accelerated, and so
will fat burning! What a
great situation! This
exemplifies just how important it is to consume the right nutrients in the
immediate period following exercise.
Since the post exercise period is
the optimal time to replenish and repair damaged muscles, this is the time
to consume easily digestible liquid carbohydrates and protein. Why liquid? This is simply because
liquid and gel sources of
carbohydrate are absorbed through the intestine and into the bloodstream
faster than solid foods, and this way
you can make sure that you are offering your body the energy it needs at
the pace it demands them. As opposed to during
the day, you actually want your insulin levels to rise so that proteins,
carbohydrates, and other nutrients can be shuttled quickly into the
starving muscles. So at this point you can indulge in those higher GI
foods! They are actually
recommended at this point because of the spike in insulin they
cause.
Though everyone’s needs are slightly
different (depending on intensity of the workout, weight of the person,
and type of workout performed), a good general rule (for someone looking
to increase lean muscle) for an immediate post-exercise drink is 0.8g of
carbohydrate and 0.4g of protein for every 1 kg of your body weight. This should be dissolved in 1L of
water. Please keep in mind
that you want minimal fat and fibre in the immediate post-exercise drink
because both slow the rate of digestion and absorption. Simple sugars are the way to go,
because they are absorbed the quickest.
For a home-made post-exercise drink, ideas for carbohydrate and protein combinations include:
Diluted Fruit Juice (Apple,
+
Hemp Protein Powder/Organic Soy Protein
Powder
(if you would like to find out about the
downside of using whey protein powder, please click
here)
+
1L Water
30 minutes to 1 hour later it is a good idea to consume something more substantial.
Shakes are perfect, as you can combine various ingredients to create a nutritious and well-structured drink. An example of a great post-exercise shake that will nourish your need for carbohydrate (as well as protein) is shown below:
1 x banana (fast acting
sugar)
1 x large scoop hemp protein powder (for more information on the benefits of hemp visit www.fitsquad.ca)
1 x spoonful on raw organic honey
(fast acting, simple sugar)
1 x tbsp Flax
Oil
3 x cups of filtered water (if you prefer a creamier drink,
substitute 1 cup of water with 1 cup of soy milk)
1 x tsp
cinnamon
1 x handful of
ice
1 x tsp almond
butter
Do not forget that you should purposely use mainly high glycemic carbohydrates after you train. Recall, you want the insulin levels to rise causing protein, carbohydrate, and other nutrients to be delivered quickly into the starving muscles.
Let us not forget PROTEIN
Those we have been focusing on
carbohydrate, it is always important to include protein in the
equation. We will be visiting
the addition of protein to your diet in the next few weeks! Watch here for more
information.