Lynn Romejko Jacobs
Southern Methodist University dallas USA
Title: Body mass index and body fat in college age males and females: Perception versus reality
Biography
Biography: Lynn Romejko Jacobs
Abstract
Objective
This study’s purpose is advancing knowledge about perceptions of healthy body fat and BMI among undergraduate students, examining the relationship between believed and actual body characteristics.
Participants
In September 2009, 413 freshmen completed a survey asking students to self-assess body fat percentage, BMI, and weight among other questions.
Methods
Students were surveyed prior to and after taking body measurements. Regression was used to understand how different categories predicted level of accuracy in students’ assessments.
Results
Findings suggest students less accurately estimated BMI than body fat percentage. Interactions suggest females and males differ in estimation accuracy, and this varied by fat categories. Additionally, 90% of students believed body fat percentage easier to understand than BMI.
Conclusions
Since body fat percentage was significantly better understood, this measurement should be used to educate individuals on healthy weight and body composition status on a wider scale.
Table 1
Summary of Actual Weight, Body Fat Percentage, and BMI
|
Variable |
n |
M |
SD |
Min |
Max |
|
Total |
|
|
|
|
|
|
Weight (lbs.) |
413 |
150.35 |
33.38 |
93 |
342 |
|
Fat % |
411 |
18.55 |
7.91 |
2.4 |
39 |
|
BMI |
409 |
22.96 |
4.05 |
15 |
47.6 |
|
Female |
|
|
|
|
|
|
Weight (lbs.) |
216 |
133.86 |
23.81 |
93 |
286 |
|
Fat % |
214 |
22.39 |
5.00 |
12.6 |
39 |
|
BMI |
213 |
22.21 |
3.66 |
15.9 |
47.6 |
|
Male |
|
|
|
|
|
|
Weight (lbs.) |
197 |
168.43 |
33.06 |
98 |
342 |
|
Fat % |
197 |
13.30 |
7.10 |
2.4 |
38 |
|
BMI |
196 |
23.78 |
4.31 |
15 |
46.5 |
Note. Measurements presented are actual numbers, not estimated predictions.
Table 2
Regression Analysis Predicting Absolute Value Difference in Weight Estimation and Weight Actual
|
Predictor |
Coefficient |
Std. Error |
95% Conf. Interval |
||
|
Minority |
-0.635 |
|
0.499 |
[-1.616, 0.346] |
|
|
Male |
-0.491 |
|
0.501 |
[-1.475, 0.494] |
|
|
Fat Indicator |
|
|
|
|
|
|
Under fat |
-1.000 |
|
0.878 |
[-2.727, 0.727] |
|
|
Over fat |
4.855 |
* |
0.997 |
[2.896, 6.815] |
|
|
Male by Fat Indicator |
|
|
|
|
|
|
Male and Under fat |
4.177 |
* |
2.059 |
[0.129, 8.225] |
|
|
Male and Over fat |
-2.220 |
|
1.354 |
[-4.883, 0.442] |
|
|
R-squared = 0.089 n = 410 |
|||||
Note. *p < .05
Table 3
Regression Analysis Predicting Absolute Value Difference in BMI Estimation and BMI Actual
|
Predictor |
Coefficient |
Std. Error |
95% Conf. Interval |
|
|
Minority |
0.586 |
|
0.549 |
[-0.595, 1.766] |
|
Male |
2.483 |
* |
0.601 |
[1.403, 3.562] |
|
Fat Indicator |
|
|
|
|
|
Under fat |
0.564 |
|
0.968 |
[-1.339, 2.468] |
|
Over fat |
0.406 |
|
0.815 |
[-1.197, 2.008] |
|
R-squared = 0.051 |
||||
|
n = 407 |
||||
Note. *p < .05