Endurance athletes use a variety of methods when it comes to
increasing time to fatigue and promoting recovery. Meaning, they are looking to find ways to go
faster, longer and recover quicker. If
you are an endurance athlete (i.e.: runner, cyclist, etc), chances are you have
used a carbohydrate supplement to boost blood glucose levels and promote
nutrient delivery during exercise lasting more than one hour.
Primarily during the first hour of moderate to intense
exercise, your body draws on glycogen stores for energy (glycogen is the
primary carbohydrate storage molecule found in the liver and muscle
tissue). The day before a big event for
an endurance athlete, they will build up glycogen stores by eating
carbohydrate-rich foods and resting their muscles. During the race, energy from the glycogen
stores will be used first and once it is gone, the body will switch to blood
glucose for quick energy. In order to
keep a steady supply of blood glucose, the athlete will consume a
fast-metabolizing source of carbohydrate at intervals throughout the race to
keep muscles working at their peak performance.
There are a variety of carbohydrate supplements on the
market like gels, chews, bars, and shots.
However, natural foods that are high in carbohydrate can offer the same
benefits during sports performance as commercial carbohydrate supplements
(1).
A study conducted at Louisiana State University found that
raisins are an effective source of fuel for endurance athletes (2). Male cyclists (n=10) were asked to complete a
2 hour glycogen depletion period followed by a 10K time trail. During the time trial, cyclist were given 1
of 2 carbohydrate supplements (sports jelly beans or sun-dried raisins). The study found no significant difference
between finish times, rate of perceived exertion, or power output for raisins
compared to sports jelly beans. The
results are shown in the table below (2).
Another study conducted at the University of California-Davis
just this past year tested the effect of sun-dried raisins vs. sports chews in
running performance (3). Eleven male
runners completed an 80-minute glycogen depletion time (running at 70% of their
VO2 max) followed by a 5K timed trial.
The participants completed the trail in three conditions (trials with
water, raisins, and sport chews) separated by seven days. The researchers found no significant
difference between sun-dried raisins and sports chews for the time to complete
the 5K.
Raisins are also a more cost effective way to achieve
essentially the same athletic performance.
The graph below illustrates the cost between raisins and commercial
products per ounce.
*Retail pricing from: http://www.gnc.com/home/index.jsp for supplements and http://www.kroger.com/Pages/default.aspx for raisins
Don’t believe it? Try
it out. Instead of loading your fuel
belt with expensive gels and bars, put in a few bags of raisins for your next
long-distance run and enjoy a 90-100 calorie handful every 20 minutes. See for yourself just how much energy you’ll
have and how much money you will save!
Sources:
1. Earnest,
CP, Lancaster, SL, Rasmussen, CJ, Kerksick, CM, Lucia, A, Greenwood, MC,
Almada, AL, Cowan, PA, and Kreider, RB. Low vs. high glycemic index carbohydrate
gel ingestion during simulated 64-km cycling time trial performance. J Strength Cond Res 18: 466–472, 2004.
2. Rietschier, H. L., Henagan, T. M., Earnest, C. P., Baker, B. L., Cortez, C. C., Stewart, L.K. Sun-dried raisins are a cost-effective alternative to sports jelly beans in prolonged cycling. The Journal of Strength and Conditioning Research, 2011, 25(11): 3150-3156.
3. Boo, T. W., Cicai, S., Hockett, K. R., Applegate, E.,
Davis, B. A., Casazza, G. A. Effect of a Natural versus Commercial Product on
Running Performance and Gastrointestinal Tolerance. Unpublished manuscript. University of California Davis.
Jill Barnes, MS, Registration Eligible is a recent graduate
of Eastern Illinois University and a Nutrition Education Specialist. Follow her blog at: http://stealthyandhealthy.wordpress.com/ or email her at jill.barnes613@gmail.com. For more information on raisins, visit:
www.loveyourraisins.com
