Diet and Nutrition Prevention of Chronic Diseases

4. Are certain dietary intakes recommended to prevent chronic diseases?

• 4.1 What are "population nutrient intake goals"?
• 4.2 How strong is scientific evidence?
• 4.3 What nutrient intakes are generally recommended for a balanced diet?
• 4.4 What level of physical activity is recommended for good health?

4.1 What are "population nutrient intake goals"?

There are no specific dietary intakes recommended for the prevention of chronic diseases, only "safe ranges" that are considered consistent with the maintenance of health in a population as a whole. If population averages fall outside this range, health concerns are likely to arise.

Table 6: Ranges of population nutrient intake goals

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.1.1 Background 

4.2 How strong is scientific evidence?

Dietary recommendations for a population should aim at minimizing the risk of developing diseases. The risk of developing a particular disease linked to a particular risk factor should be assessed based on the results of multiple controlled trials. Moreover, the risk of many diet-related problems is also linked to environmental factors which lead to changes in behaviour and particularly to excess weight gain.

Scientific evidence can be classified as convincing, probable, possible, or insufficient depending on the number and type of studies carried out and the consistency of the results.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.1.2 Strength of evidence 

4.3 What nutrient intakes are generally recommended for a balanced diet?

Table 6 presents the population nutrient intake goals proposed by the Joint WHO/FAO Expert Consultationto the national and regional bodies responsible for establishing dietary recommendations for the prevention of diet-related chronic diseases. These goals are expressed in numerical terms, rather than as increases or decreases in intakes of specific nutrients, because the desirable change will depend upon existing intakes in the particular population, and could be in either direction.

Table 6: Ranges of population nutrient intake goals

The recommended range for total fat is 15 to 30% of total dietary energy intake, whereas the minimum fat intake, which is considered consistent with good health, is 20%. However, highly physically active groups with diets rich in vegetables, legumes, fruits and wholegrain cereals may consume a total fat intake of up to 35% without the risk of unhealthy weight gain.

Higher intakes of free sugars threaten the nutrient quality of diets by providing significant energy without specific nutrients. Drinks that are rich in free sugars increase overall energy intake by reducing appetite control. Thus, restriction of free sugars is likely to contribute to reducing the risk of unhealthy weight gain. To this length, the WHO recommends a population goal for free sugars of less than 10% of total energy intake. It is recognized, with respect of the prevention of obesity, that setting such a goal for the average free sugar intake of a population remains controversial (Comment).

The recommended intake of fruits and vegetables combined with the consumption of wholegrain cereals is likely to provide an adequate amount of total dietary fibre, i.e. more than 25 g per day.

To assess the weight status of an adult the body mass index (BMI) is calculated by dividing weight in kilograms (kg) by the height in meters squared (m²). The goal for individuals is to maintain a BMI in the range of 18.5-24.9kg/m² and to avoid a weight gain of more than 5 kg during adult life.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.1.3 A summary of population nutrient intake goaly 

4.4 What level of physical activity is recommended for good health?

It is recommended that people of all ages engage in at least 30 minutes of moderate physical activity (such as brisk walking) every day. This level of activity, which is found to be sufficient for maintaining cardiovascular health, is particularly relevant for those who lead otherwise inactive lives.

For most people, engaging in a higher level of physical activity for a longer period of time can provide even greater health benefits. At least 60 minutes a day of moderate-intensity activity is recommended in order to prevent obesity.

Additionally, it is recommended that adults engage in strength training exercises at least twice a week in order to maintain muscle strength, and hence preserve independence in performing the activities of daily life and reduce the risk of falling.

The recommended daily activity can be accomplished in several short sessions and can include physical tasks performed in the home (such as household chores) or at work.

When determining an appropriate level of physical activity, potential benefits and risks should be considered on an individual basis.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.1.3 A summary of population nutrient intake goals, Physical activity