The Psychology of Eating: From Healthy to Disordered Behavior

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.