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5. Population nutrient intake goals for preventing diet-related chronic diseases: Previous page | 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27

5.2.5 General strategies for obesity prevention

The prevention of obesity in infants and young children should be considered of high priority. For infants and young children, the main preventive strategies are:

  • the promotion of exclusive breastfeeding;
  • avoiding the use of added sugars and starches when feeding formula;
  • instructing mothers to accept their child’s ability to regulate energy intake rather than feeding until the plate is empty;
  • assuring the appropriate micronutrient intake needed to promote optimal linear growth.

For children and adolescents, prevention of obesity implies the need to:

  • promote an active lifestyle;
  • limit television viewing;
  • promote the intake of fruits and vegetables;
  • restrict the intake of energy-dense, micronutrient-poor foods (e.g. packaged snacks);
  • restrict the intake of sugars-sweetened soft drinks.

Additional measures include modifying the environment to enhance physical activity in schools and communities, creating more opportunities for family interaction (e.g. eating family meals), limiting the exposure of young children to heavy marketing practices of energy-dense, micronutrient-poor foods, and providing the necessary information and skills to make healthy food choices.

In developing countries, special attention should be given to avoidance of overfeeding stunted population groups. Nutrition programmes designed to control or prevent undernutrition need to assess stature in combination with weight to prevent providing excess energy to children of low weight-for-age but normal weight-for-height. In countries in economic transition, as populations become more sedentary and able to access energy-dense foods, there is a need to maintain the healthy components of traditional diets (e.g. high intake of vegetables, fruits and NSP). Education provided to mothers and low socioeconomic status communities that are food insecure should stress that overweight and obesity do not represent good health.

Low-income groups globally and populations in countries in economic transition often replace traditional micronutrient-rich foods by heavily marketed, sugars-sweetened beverages (i.e. soft drinks) and energy-dense fatty, salty and sugary foods. These trends, coupled with reduced physical activity, are associated with the rising prevalence of obesity. Strategies are needed to improve the quality of diets by increasing consumption of fruits and vegetables, in addition to increasing physical activity, in order to stem the epidemic of obesity and associated diseases.

5.2.6 Disease-specific recommendations

Body mass index (BMI)

BMI can be used to estimate, albeit crudely, the prevalence of overweight and obesity within a population and the risks associated with it. It does not, however, account for the wide variations in obesity between different individuals and populations. The classification of overweight and obesity, according to BMI, is shown in Table 8.

Classification

BMI (kg/m2)

Risk of comorbidities

Underweight

<18.5

Low (but risk of other clinical problems increased)

Normal range

18.5 - 24.9

Average

Overweight

≥25.0



Pre-obese

25.0 - 29.9

Increased

Obese class I

30.0 - 34.9

Moderate

Obese class II

35.0 - 39.9

Severe

Obese class III

≥40.0

Very severe

a These BMI values are age-independent and the same for both sexes. However, BMI may not correspond to the same degree of fatness in different populations due, in part, to differences in body proportions. The table shows a simplistic relationship between BMI and the risk of comorbidity, which can be affected by a range of factors, including the nature and the risk of comorbidity, which can be affected by a range of factors, including the nature of the diet, ethnic group and activity level. The risks associated with increasing BMI are continuous and graded and begin at a BMI below 25. The interpretation of BMI gradings in relation to risk may differ for different populations. Both BMI and a measure of fat distribution (waist circumference or waist: hip ratio (WHR)) are important in calculating the risk of obesity comorbidities.

Source: reference 26.

In recent years, different ranges of BMI cut-off points for overweight and obesity have been proposed, in particular for the Asia-Pacific region (27). At present available data on which to base definitive recommendations are sparse.1 Nevertheless, the consultation considered that, to achieve optimum health, the median BMI for the adult population should be in the range 21-23 kg/m2, while the goal for individuals should be to maintain BMI in the range 18.5-24.9 kg/m2.

Waist circumference

Waist circumference is a convenient and simple measure which is unrelated to height, correlates closely with BMI and the ratio of waist-to-hip circumference, and is an approximate index of intra-abdominal fat mass and total body fat. Furthermore, changes in waist circumference reflect changes in risk factors for cardiovascular disease and other forms of chronic diseases, even though the risks seem to vary in different populations. There is an increased risk of metabolic complications for men with a waist circumference ≥102 cm, and women with a waist circumference ≥88 cm.

1 A WHO Expert Consultation on Appropriate BMI for Asian Populations and its Implications for Policy and Intervention Strategies was held in Singapore from 8 to 11 July 2002 in order to: (i) review the scientific evidence on the relationship between BMI, body composition and risk factors in Asian populations; (ii) examine if population specific BMI cut-off points for overweight and obesity are necessary for Asian populations; (iii) examine the purpose and basis of ethnic-specific definitions; and iv) examine further research needs in this area. As one of its recommendations, the Consultation formed a Working Group to examine available data on the relationship between waist circumference and morbidity, and the interaction between BMI, waist circumference and health risk in order to define future research needs and develop recommendations for the use of additional waist measurements to further define risks.

5. Population nutrient intake goals for preventing diet-related chronic diseases: 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27 | Next page

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