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Relationship Between Body Mass Index and Nutrition and Exercise Knowledge

1 August 2007


Background: Obesity has become the most prevalent nutritional problem in the world and the United States has one of the highest rates. Research indicates that a quarter of children and more than half of adults classify as overweight with rates expected to soar. Being overweight or obese increases the risk of many diseases and health conditions and has been shown to reduce life expectancy particularly in younger ages. Some underlying causes include individual behaviors, environmental factors, and genetics. Overweight and obesity are a result of energy imbalance over a long period of time. Research has shown that eating a variety of foods, including plenty of vegetables, fruits, and whole grain products is crucial to maintaining a healthy weight. Body mass index (BMI) is an approximate measure of body fat based on height and weight. Many people are concerned about their overall weight, but what matters most is how much of your body weight is fat. Knowing what a healthy BMI is can help an individual set a realistic and appropriate weight goal. BMI is an inexpensive and easy-to perform method of screening for weight categories that may lead to health problems.

Hypothesis: The researchers' hypothesis was that the more knowledge a person has of nutrition and exercise, the more likely they are to have a healthy body mass index.

Methods: The main instrument used for this study was a questionnaire created by the primary investigators. The questions did· not come from a previously published questionnaire. The questions addressed basic knowledge of nutrition and exercise. The questions were multiple choice with only one right answer. Participants (N=88) spent an average often minutes completing the survey and having their height and weight measured.

Results: The mean for males with survey questions answered correctly was 5.38 and the mean for women was 5.00 of 10. A positive correlation was found between higher survey scores and amount of exercise per week. (r=0.2641, p=0.0131). Those who had a normal BMI or less had a mean of 5.37 for questions answered correctly on the survey and those who had a non-ideal BMI had a mean of 5.02 for questions answered correctly. Almost half of study participants (48.9%) assessed their own BMI as normal when only 42% of participants actually fit into the normal range for BMI. There were 20 participants whose BMI classified as obese or morbidly obese when only 4 participants actually considered themselves as such. Self reported weight and age are positively correlated (r=0.3122, p=0.0032). Those who had an incorrect perception of their weight were statistically heavier (p= 0.0026). Self report of weight and BMI are positively correlated (r=0.6958, p= 0.0000). Self reported weight and exercise per week were negatively correlated (r=-0.3875, p= 0.0002).

Conclusion: The results of this study showed that knowledge of diet and exercise does not correlate with BMI. However, this study did positively correlate a higher overall BMI with an incorrect perception of BMI by participants. In regards to the incorrect perception of one's BMI, this maybe a stepping stone to educate people to learn more about BMI in hopes that they will strive to reach a healthier BMI.


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