1. Weight for Height BPK 303 Summer 2015

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 KIN-Scale proportional breadths & widths represent a detailed appraisal of frame size Range of Humerus Width (cm) for Medium Frame Size by Height group

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 F t  Where F t = 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 – F x )  Where F x = fractional expression of % body fat

8.  Assumes no change in FFM as Body Fat changes  Not recommended since based upon a % Fat with considerable error in individual estimates (SEE = 3.7% Fat) 8 Calculation of optimal weight range

9. Body Mass Index (Quetelet Index - 1833)

10. 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] = HT 2  During development: the squares of weight were related to the fifth powers of height: [WT] 2 = HT 5 → [WT] = HT 2.5 10

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

12. Correlational Analysis of Weight (WT) and Height (HT) indices in a sample of SFU Kin 303 students (aged 18–25 years) 12 Ward R, Anderson G. 2012 (unpublished)

13. Sum of 6 Skinfolds vs BMI KIN-Scale Males and Females 13

14. Ross et al. 1988  Correlations of BMI are “good” with sum of skinfold corrected-girths and even bone widths Correlations of BMI with sums of selected anthropometric measures (Canada Fitness Survey 1981) Sum of 5 Skinfolds Sum of corrected Limb Girths Sum of Bone Breadths Males 0.670.560.36 Females 0.720.480.42

15. Correlational Analysis of Weight (WT) and Height (HT) indices in a sample of SFU Kin 303 students (aged 18–25 years) 15 Ward R, Anderson G. 2012 (unpublished)

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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) 17

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) 18

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

20. Children & Youth 20 During development: the squares of weight were related to the fifth powers of height: [WT] 2 = HT 5 → [WT] = HT 2.5

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

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23. CDC BMI Growth Charts 23

24. 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