Download Running head: OMNIVOROUS OR VEGETARIAN DIET

Running head: OMNIVOROUS OR VEGETARIAN DIET
Omnivorous Diet or Vegetarian Diet: Are There Differences in Muscle Growth?
Andy Jensen
Southwestern Adventist University
KINT 201 Introduction to Kinesiology Research
Vesa Naukkarinen, MS, ACSM-CPT, ACSM-HFS, CSCS
April 10, 2014
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Introduction
Vegetarian diets have been gaining much popularity in the several decades. Until recently
most nutrition scientists have discarded vegetarian diets. Claiming that a vegetarian diet is not
sufficient, and that someone who practices a vegetarian diet will be lacking in several key areas
of nutrition such as iron, zinc, vitamin B12, vitamin D and calcium. These vitamins and nutrients
are commonly found in meat or fortified dairy products (e.g., milk fortified with Vitamin D).
However recent research has shown that these vitamin and mineral needs can easily be met with
a well-balanced vegetarian diet (Venderley & Campbell 2006).
Since the vegetarian diet is gaining so much popularity it is important that we apply the
scientific method to testing the benefits and disadvantages of removing meat from diets. Every
year the scientific community publishes more and more research and findings related to
vegetarian diets. So far the majority of information has been positive but many areas need to be
studied further. Current research confirms that a vegetarian diet is rather sufficient for the
majority of the population if it is well planned and diversified (Craig & Mangels 2009).
With many athletes now transitioning to a vegetarian based diet, there is concern as to
how this may affect responses to cardiorespiratory and resistance training. A few studies on the
effect of a vegetarian diet and cardiorespiratory training have already been conducted and found
that a vegetarian diet does not change cardiorespiratory conditioning for better or for worse
(Venderlay & Campbell 2006). There is still much debate over whether a vegetarian diet can be
used for individuals wanting to efficiently increase muscle mass through means of resistance
training. The common belief is that omnivorous diets are more beneficial on muscular
development than vegetarian diets because of the quality of protein found in meat products that
are not available in other forms. However, this topic has been studied on relatively small scales
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and only with a very limited demographic (i.e., elderly men) (Campbell et al., 1999). The
purpose of this study is to determine the extent to which lacto-ovo-vegetarianism is an advantage
for particularly young athletes.
Review of Literature
In 2009 the American Dietetic Association (ADA) published an official position on
vegetarian diets. The ADA said that if a vegetarian diet is well planned it can be nutritionally
sufficient and healthy. Vegetarian diets show a positive correlation with lower risk of death from
heart disease, lower LDL levels, lower rates of hypertension, lower BMI and even lower overall
cancer rates. These health benefits are thought to be from lower dietary amounts of cholesterol
and saturated fats plus a higher dietary amount of fruits, grains, vegetables, fiber, phytochemicals
and more (Craig & Mangels, 2009).
Other benefits to a vegetarian diet were described in a study conducted in the mid 1980s
in the United Kingdom. In the study 6,000 vegetarians and 5,000 non-vegetarian participants
were recruited for a comprehensive 12- year observation. At the end of the 12-year study,
researchers discovered that the vegetarian participants had a significantly lower mortality rate
from malignant neoplasms during the study than their non-vegetarian counterparts (Lindbloom,
2009).
Two studies compared muscle development in older males between omnivores and
vegetarians, lactoovovegetarians to be precise. The first study found that muscle gains were the
same between the two groups. The researchers concluded that protein levels where the main
predictor and that the source of the protein was not especially significant (Tufts University,
2002). The second study, on the other hand, found that those who ate meat had a significantly
larger improvement in muscle mass after a twelve week exercise program. The study however
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failed to specify how much protein each group should be eating daily. The meat eating group
was instructed to eat their normal diet and to not try to gain or lose any weight or alter the types
of food that they ate. The lacto-ovo-vegetarian (LOV) group was given a brief dietary counseling
session with a research dietitian and a vegetarian cook book to help them plan their meals.
Besides that guidance the vegetarian group was not instructed any further as to what type and
quantity of food they should be eating daily. This indicates a major flaw in the execution of the
study and the results cannot be fully trusted (Campbell et al., 1999).
There is evidence that a vegetarian diet could reduce exercise-induced oxidative stress
levels. Oxidative stress is a term that describes “an imbalance between free radical production
and the ability of the antioxidant defense system of the body to neutralize free radicals” (Trap,
Knez & Sinclair, 2010, p. 1261). Oxidative stress is a normal response to exercise. Although
exercise is very important for the body, this side effect can be less than desirable. Free radicals
are not always bad; they are influential in speeding up wound healing and aid in building an
efficient immune response. But these free radicals also disturb the regulation of apoptosis and
promote heart disease and certain forms of cancer (Trapp, Knez & Sinclair, 2010).
On average, vegetarians have much higher levels of antioxidants in their body than meat
eaters. Antioxidants counteract the negative effects of free radicals without interfering with the
positive effects of the free radicals. Antioxidants are most abundant in fruits and vegetables, so it
follows that vegetarians would have higher antioxidant levels. Although more research needs to
be done in this field, it is a very promising subject and may be a major step toward the
acceptance of a vegetarian diet (Trapp, Knez & Sinclair, 2010).
Another study that focused on the vegetarian diet and oxidative stress found that nonvegetarians had higher incidences of DNA strand breaks and oxidized purine nucleotides than
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vegetarians. The most significant area of decreased DNA damage was found to be in the immune
system, specifically in lymphocytes. These findings were highly indicative of a positive
correlation between immunity against oxidative stress and a vegetarian diet. Researchers also
discovered that although there was a positive connection between chromosome irregularities and
age in non-vegetarians, the opposite was true for vegetarians. In fact, researchers found that age
and chromosome divergence seemingly had no connection whatsoever in vegetarians
(Kazimirova, et al., 2004).
Hypothesis
For the purpose of this study my null hypothesis is that there is no statistically
significant difference in muscular development after the resistance training program between the
omnivorous diet group and their LOV counterparts.
Methods
To test my hypothesis, 60 males between the ages of 18-26 will be recruited. Subjects
will be recruited through a convenience sample meant to gather individuals frequenting local
Fort Worth gyms and health clubs. Subjects will then be selected according to body mass index
(BMI) calculations and nonsmoking status. Individuals meeting nonsmoking criteria and falling
within a BMI calculation of 18-25 will be selected until 60 participants are recruited.
Two groups will be created through random assignment. One group will participate in an
omnivorous diet while the other group maintains a lacto-ovo-vegetarian (LOV) diet. The two
groups will continue on this diet for a six week period. It is imperative that both groups strictly
adhere to the same nutritional guidelines set up by the researchers, these guidelines include a
daily diet containing: 30% protein, 20% fat and 50% carbohydrates. The daily caloric intake for
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each participant will be set by a dietician, depending on the participant’s individual caloric
needs.
Participants will keep an online food journal through a program called Vitabot which
calculates micronutrients, macronutrients, proteins, fats, carbohydrates and caloric intake for
each food selection. The initial meeting with participants will include a physical health
assessment to be used as a baseline measurement. Participant’s medical background including
medications, surgeries, family history, and medical diagnoses will be gathered at that time, and
those deemed as being too high risk for moderate physical activity will be dismissed and
replaced as needed.
The participants will then be given a one repetition maximum (RM) test in the bilateral
seated leg curl, double leg press, bilateral knee extension, bench press, and seated arm pull
exercises in order to have a baseline measurement for comparison at the end of the six week
study. These measurements will be used to set the training intensity for each individual subject.
In addition, the widest part of the upper arms and thighs will also be measured and compared to
final data at the conclusion of the study. Subjects will meet three times a week on
nonconsecutive days at Southwestern Adventist University’s gymnasium. Each exercise training
session will start with a 10 minute jogging warm up.
Participants will do 85% of their one RM weight, with 3 sets and 6-8 repetitions in a set.
Afterwards participants will have a cool down and stretch period. Each participant will be
assessed for the one RM at the end of the second and fourth week and adjustments in weight will
be made accordingly. At the end on the sixth week participants will once again perform a one
repetition maximum test in all five exercises, the widest part of the upper arms and thighs will be
measured, and results will be compared to beginning measurements.
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Data will be interpreted using a two-tailed t-test with alpha set at 0.05 to test the
statistical significance of the results. This data will then be used to either accept or reject my
null hypothesis. Rejection or acceptance will be made based on the p-value in relation to alpha.
If the p-value is < alpha my null hypothesis will be rejected, if the p-value is > alpha I must fail
to reject alpha indicating statistically significant data.
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References
Campbell, W. W., Barton, M. L., Cyr-Campbell, D., Davey, S. L., Beard, J. L., Parise, G. &
Evans, W. J. (1999). Effects of an omnivorous diet compared with a lactoovovegetarian
diet on resistance-training-induced changes in body composition and skeletal muscle in
older men. American Journal for Clinical Nutrition, 70, 1032-1039.
Craig, W. J. & Mangels, A. R. (2009). Position of the American dietetic association: Vegetarian
diets. Journal of the American Dietetic Association, 109(7), 1266-1282. doi:
10.1016/j.jada.2009.05.027.
Do you need meat to beef up?. (2002). Tufts University Health & Nutrition Letter, 20(8), 2.
Kazimirova, A., Barancokova, M., Volkovova, K., Staruchova, M., Krajcovicova-Kudlackova,
M., Wsolova, L., Collins, A. & Dusinska, M. (2004). Does a vegetarian diet influence
genome stability? European Journal of Nutrition, 43(1), 32-38. doi: 10.1007/s00394-0040436-8.
Lindbloom, E. J. (2009). Long-term benefits of a vegetarian diet. American Family Physician,
79(7), 541-542.
Trapp, D., Knez, W., Sinclair, W. (2010). Could a vegetarian reduce exercise-induced oxidative
stress? A review of the literature. Journal of Sports Sciences, 28(12), 1261-1268. doi:
10.1080/02640414.2010.507676.
Venderley, A. M. & Campbell, W. W. (2006). Vegetarian diets: Nutritional considerations for
athletes. The American Journal of Sports Medicine, 36(4), 293-305.