Bma Illustrated Medical Dictionary

144 146 148 150 152 154 156 158 160 162 164 166 168 170 172 174

57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76

176 178 180 182 184 186 188 190 192 194cm

in

95

90

85

80

75

70

65

60

55

50

45

40

210

200

190

180

170

160

150

140

130

120

110

100

90

lb kg

Weight lossor weight gain occurs if the

net balance is disturbed.

Weight can be compared with standar-

dized charts for height, age, and sex. At

all ages, divergence from the normal

weight for height may have medical

implications. For example, if weight is

below 80 per cent of the standard

weight for height, the individual’s nutri-

tionis probably inadequate as a result

of poor diet or disease, and if 20 per

cent above the standard, he or she is

considered to be suffering from obesity.

An alternative method of assessment is

use of the body mass index(BMI, or

Quetelet’s index), obtained by dividing

weight in kilograms by the square of

height in metres. A healthy weight is

20–25 BMI; a BMI of greater than 25 indi-

cates that a person is overweight.

weight lossThis occurs any time there

is a decrease in energyintake compared

with energy expenditure. The decrease

may be due to deliberate weight reduc-

tionor a change in diet or activity level.

It may also be a symptom of a disorder.

Unexplained weight loss should always

be investigated by a doctor.

Many diseases disrupt the appetite,

which may lead to weight loss. Depres-

sionreduces the motivation to eat, peptic

ulcercauses pain and possible food

avoidance, and some kidney disorders

cause loss of appetite due to the effect of

uraemia. In anorexia nervosaand bulimia,

complex psychological factors affect an

individual’s eating pattern.

Digestive disorders, such as gastro-

enteritis, lead to weight loss through

vomiting. Cancer of the oesophagus (see

oesophagus, cancer of) and stomach

cancercause loss of weight, as does

malabsorption of nutrients in certain

disorders of the intestine or pancreas.

Some disorders cause weight loss by

increasing the rate of metabolic activity

in cells. Examples are any type of cancer,

chronic infection such as tuberculosis,

and hyperthyroidism. Untreated diabetes

mellitusalso causes weight loss due to

a number of factors.

weight reductionThe process of los-

ing excess body fat. A person who is

severely overweight (see obesity) is more

at risk of various illnesses, such as dia-

betes mellitus, hypertension(high blood

pressure), and heart disease.

The most efficient way to lose weight

is to eat 500–1,000 kcal (2,100–4,200 kJ)

a day less than the body’s total energy

requirements. Exercise also forms an

extremely important part of a reducing

regime, burning excess energy and

improving muscle tone.

In most circumstances, drugs play lit-

tle part in a weight loss programme.

WEIGHT LOSS WEIGHT REDUCTION

W

WEIGHT

WEIGHT

HEIGHT

Overweight

(BMI > 25)

Underweight

(BMI < 20)

WEIGHT ASSESSMENT CHART

Healthy weight

(BMI 20–25)