|Activity, Energy Expenditure and Energy Requirements of Infants and Children (IDECG, 1989, 412 p.)|
(Discussion leader W. DIETZ, rapporteur W.P.T. JAMES)
Although there have been few developments in the treatment of childhood obesity, a picture is emerging of what should be done to prevent obesity. In childhood, as distinct from infancy, many societies have shown a secular trend towards a reduction in physical activity, and this has been accompanied by a progressive fall in food intake. There may be greater difficulty in allowing the normal control of appetite to operate when children and adults are inactive and a wide choice of tempting, energy-rich food is easily available. There are hints that the obesity-prone child tends to be less physically active and that there is a breakdown in the normal physiological regulation of food intake. The quality of the diet, i.e., its high energy density, particularly from fat, may also be conducive to weight gain.
The problem of specifying requirements to prevent childhood obesity is substantial; one can identify a minimum energy need, but thereafter it seems necessary to specify a reasonable degree of physical activity to prevent obesity. How much activity is needed to reduce the rate of obesity is, however, unknown.
There is little coherent evidence in humans that rapid weight gain in infancy leads to obesity in adults. Most adult obesity of early onset stems from childhood rather than infancy, so that a proposal to reduce food intake in infancy, in order to prevent adult obesity, is probably unwise at this stage. The long-term programming in infancy of energy and nutrient metabolism needs, however, to be assessed because of its public health implications.
There are subgroups within the population which have special problems in relation to energy requirements. Handicapped children may need special care because their requirements may be very low if they are inactive and confined to a wheelchair or bed, whereas some other children may have special needs because of high rates of energy expenditure.