1 / 25

Weight for Height

BPK 303. Weight for Height. Fall 2013. Desirable Body Weight. Desirable, ideal, optimal “What weight should I be?” Weight for height Weight for height with frame size Weight with optimal % body fat BMI - Body Mass Index. Weight for Height. Epidemiologists needed a measure of obesity

thelma
Download Presentation

Weight for Height

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. BPK303 Weight for Height Fall 2013

  2. Desirable Body Weight • Desirable, ideal, optimal • “What weight should I be?” • Weight for height • Weight for height with frame size • Weight with optimal % body fat • BMI - Body Mass Index

  3. Weight for Height • Epidemiologists needed a measure of obesity • Often questionnaire data on height and weight alone • “Ideal” and “Desirable” Weight tables • Metropolitan Life Weight for Height Tables

  4. Weight for Height Tables Metropolitan Insurance Co., 1983, weights at ages 25-59 based on lowest mortality. Weight in pounds according to frame (in indoor clothing weighing 3 lbs., shoes with 1" heels).

  5. Frame Size Estimate of Skeletal Proportion

  6. Weight for Optimal % Body Fat • If you know the current % body fat, weight for any optimal % body fat can be calculated. Consensus of an expert panel (1986). Arbitrary cut-off points.

  7. Calculation of optimal weight range • 1. Calculate Fat Weight (FW) • FW = body weight x Ft • Where Ft = fractional expression of % body fat • 2. Calculate Fat-Free Weight (FFW) • FFW = Body Weight – FW • 3. Calculate the desired target weight (TW) • TW = FFW / (1 – Fx) • Where Fx = fractional expression of % body fat

  8. Example Calculation: Young Male Current weight =100kg, %body fat = 34% • 1. Calculate Fat Weight (FW) • FW = body weight x Ft • FW = 100 x .34 = 34kg • 2. Calculate Fat-Free Weight (FFW) • FFW = Body Weight – FW • FFW = 100 – 34 =66kg • 3. Calculate the desired target weight (TW) • TW = FFW / (1 – Fx) • @ 12%; TW = 66 / (1 - .12) = 66 / 0.88 = 75kg • @ 18%; TW = 66 / (1 - .18) = 66 / 0.82 = 80.5kg

  9. Weight range taking into account error in determination of % body fat • 95% confidence estimates of % body fat • % Fat (1.96 x S.E.E.) • 34 (1.96 x 3.7) = 26.7 to 41.3% body fat • 95% confidence estimates of FFW are: • upper limt FFW = 100 – 26.7 = 73.2kg • lower limit FFW = 100 – 41.3 = 58.7kg • Lower limit for target weight at 12% body fat • TW = 58.7 / (1 - .12) = 58.7 / 0.88 = 71.6kg • Upper limit for target weight at 18% body fat • TW = 73.2 / (1 - .18) = 73.2 / 0.82 = 83.2kg

  10. Body Mass Index (Quetelet Index - 1833)

  11. Quetelet (1833) • Tall adults are more linear than short adults. • Fully developed individuals: the weight of an individual at different heights is related to the square of the stature: [WT] = HT2 • During development: the squares of weight were related to the fifth powers of height: [WT]2 = HT5 → [WT] = HT2.5

  12. Canada Fitness Survey (1981) (20-29 years old)

  13. Correlational Analysis of Weight (WT) and Height (HT) indices in a sample of SFU Kin 303 students (aged 18–25 years) Ward R, Anderson G. 2012 (unpublished)

  14. Sum of 6 Skinfolds vs BMIKIN-Scale Males and Females

  15. Ross et al. 1988 • Correlations of BMI are “good”with sum of skinfold corrected-girths and even bone widths

  16. Correlational Analysis of Weight (WT) and Height (HT) indices in a sample of SFU Kin 303 students (aged 18–25 years) Ward R, Anderson G. 2012 (unpublished)

  17. Percentage body fat as measured by dual-energy X-ray absorptiometry (DXA %fat) versus BMI and 1/BMI in women from 3 study sites combined. Reproduced from Gallagher (2000)

  18. Percentage body fat by dual-energy X-ray absorptiometry (DXA %fat) versus 1/BMI by sex for each of the study sites. Reproduced from Gallagher (2000)

  19. Predicted percentage body fat by sex and ethnicity based on 4-C percentage body fat

  20. Children & Youth During development: the squares of weight were related to the fifth powers of height: [WT]2 = HT5 → [WT] = HT2.5

  21. B-values of height predicting weight in yearly age groups for Canada Fitness Survey (CFS) and Coquitlam Growth Study (COGRO) boys and girls

  22. CDC BMI Growth Charts

  23. BMI • BMI is not an indicator of body fat in individuals it is a measure of weight for height • It can be useful as a population screening and awareness device, but not in individual prescription • May be useful used in conjunction with other measures

More Related