150 Obesity
percentage body fat directly. At its most basic this involves assessing
skinfold thickness using calipers, normally around the upper arm and the
upper and lower back. This is not suitable for those individuals who are
severely obese, and it misses abdominal fat. At a more advanced level, body
fat can be measured using bioelectrical impedance, which involves passing
an electrical current between a person’s hand and foot. As water conducts
electricity and fat is an insulator, the impedance of the current can be used
to calculate the ratio between water and fat and therefore an overall
estimate of percentage body fat can be made.
Weight (kg)
150
140
130
120
110
100
90
80
70
60
50
40
320
300
280
260
240
220
200
180
160
140
120
100
Weight (lb)
1.5 1.6 1.7 1.8 1.9
Height (meters)
58 60 62 64 66 68 70 72 74
Height (inches)
0 – normal weight
1 – overweight
2 – clinical obesity
3 – severe obesity
2
1
0
3
Figure 8.1 Grades of obesity by height and weight.