Annex 1

Print PDF

The importance of a low sugar intake in maintaining a normal body weight, avoiding type 2 diabetes and also preventing dental caries in children and adults

Consuming too much and too many foods and drinks rich in sugar increases the concentration of energy per unit weight in foods and this means that, given the less effective brain regulatory systems for preventing weight gain rather than weight loss, children and adults, particularly if they are genetically sensitive, will gain weight (1). A high level of free sugars intake increases energy intake without children and adults realizing; it is also associated with a poor quality diet, which is often short of important nutrients. 

There is now consistent evidence that the intake of free sugars – particularly in the form of sugar-sweetened beverages – not only increases overall energy intake but is also liable to reduce the intake of nutritious foods so the diet becomes more unhealthy. This then amplifies the increased risk that weight gain and obesity causes increases in heart disease, strokes, some cancers, as well as diabetes. Another reason why more sugary diets increase intake is not only that they trigger taste buds which specifically respond to sugar but brain scanning studies also now show that repeated high sugar intakes lead to neurochemical changes in that part of the brain involved in releasing dopamine which seems to be involved in the sense of reward. The primaeval drive for food involves an enhanced desire to obtain energy-rich foods, traditionally in the form of carbohydrate with fruit, e.g. dates and honey serving as sources of rapidly digested energy. These sugars then trigger the specific taste buds linked to the centres of the brain associated with reward. There is now some evidence that this can lead in our modern world environment to a state of dependency (2) and certainly we can become habituated as individuals and as a population to foods that are much sweeter. Therefore, as with salt, a steady progressive reduction in sugar in the diet allows the taste-reward system to readjust and respond well to much lower sugar intakes. This explains why individuals who give up sugary drinks by not adding sugar to tea or coffee after a few weeks then find these drinks far too sweet for their liking.

The other reason why sugar in the diet tends to make us consume too much energy is that sugar is, like fat, a concentrated form of energy so the energy density of the diet, i.e. in terms of kcal/100g of food increases as diets are enriched in sugars. Many studies have now shown that the energy density of the diet is the key feature which allows individuals to “passively over consume”, i.e. they do not realize they have eaten so much energy because they have eaten so little food. So a poor diet rich in sugar and fat with little fiber, vegetables and fruit can satisfy our energy demands with only 750g of food each day, whereas a low fat, low sugar fiber-rich cereal diet with vegetables and some fruit needs an input of 3kg of these foods to provide the same energy intake as 750g of a poor quality high fat and sugar-enriched diet (3). This “passive over- consumption” is therefore a key to inadvertently eating more calories in the diet (4) so this leads to weight gain unless physical activity is routinely increased. So given that reducing energy density of the diet leads to less energy being eaten this means that we should be progressively reducing both the sugar and total fat content of the Eastern Mediterranean diet. This progressive reformulation of foods is a key measure that can be expected to reduce progressively the national burden of ill-health. 

Sugar in many forms of drink, i.e. soft drinks, milk shakes, etc. on the basis of clinical trials and some longitudinal studies leads to a greater likelihood of weight gain (5,6) because they are energy rich and these drinks seem to evade the normal brain regulatory processes to an even greater extent than energy-rich foods. So energy-rich drinks are particularly conducive to weight gain. Artificial sweetened drinks also seem to increase the risk of diabetes but mainly by promoting weight gain and obesity. 

Some additional analyses by government scientific bodies also suggest that the intake of sugary drinks promotes the development of diabetes (7) not only by increasing weight but also by independently inducing the diabetic state, a feature that the latest WHO scientific committee did not assess (8). The mechanism in part involves the way that the fructose part of sugar has to be metabolized in the liver and too much dietary fructose then leads to a fatty liver which, in addition to being a hazard for future cirrhosis of the liver, leads to changes in insulin production and the sensitivity of the body to the insulin being produced. This then leads to a pre-diabetic state of poor glucose handling and then to diabetes itself. Weight gain itself is also known to induce the risk of heart disease, stroke, and some cancers, as well as diabetes.

New systematic analyses suggest that an extra soft drink a day increases the risk of diabetes by nearly a fifth (18%) and if the contribution of weight gain to the development of diabetes is removed then each daily sweet drink still increase the risk of diabetes by 13%. The evidence on fruit juice and the risk of diabetes is less impressive but the studies only considered countries with a far lower fruit juice intake than those seen in the Eastern Mediterranean Region (9). The UK Government’s Scientific Expert Committee report also assessed these drinks in relation to the development of diabetes and found a clear link to the development of diabetes independent of weight gain. So sugary drinks are now considered to increase the risk of diabetes, as well as obesity.

Sugar intake is also the fundamental cause of tooth decay that affects children with their first set of teeth and carries on inducing serious dental erosion and decay throughout life, i.e. into the eighth decade of life. Caries is not only one of the most costly diseases affecting countries but it also induces infections in children leading to emergency hospital admissions. It also impairs their physical growth and their attendance and learning ability at school (10).

In practice, almost all countries globally now have too much sugar in their diet if the lower WHO advised figure for individuals is taken as 5% for all individuals (suggesting in practice an average optimum population intake of 2%–3%). Many European countries are now planning to reduce the average intake by half so, given the huge burden of diabetes and cardiovascular disease in the Eastern Mediterranean Region, there is a need to consider how to reduce the sugar in the Region’s food chain by at least 50% over the next few years. This is a major challenge which can only be handled over a period of 5–10 years but where rapid benefits may well emerge as sugar intakes fall. It is therefore suggested that the avoidance of sugar-rich drinks should be one of the first priorities for improving health in the Eastern Mediterranean Region

References

1) Diet, nutrition and the prevention of chronic diseases. Report of a Joint WHO/FAO Expert Consultation. WHO Technical Report Series No. 916, Geneva: WHO; 2003.

2) Wang G-J, Volkow NK, Fowler JS. Dopamine deficiency, eating and body weight. In Food and Addiction. A Comprehensive Handbook. Eds Brownell KD, Gold MK. Oxford: Oxford University Press; 2012;185–193.

3) Prentice AM, Jebb SA. Fast foods, energy density and obesity: a possible mechanistic link. Obesity Rev. 2003;4:187–94.

4) Karl JP, Roberts SB. Energy density, energy intake, and body weight regulation in adults. Adv Nutr. 2014;5:835–50.

5) Funtikova AN, et al. Soft drink consumption is positively associated with increased waist circumference and 10-year incidence of abdominal obesity in Spanish adults. J Nutr. 2015;145:328–34.

6) Field AE, et al. Association of sports drinks with weight gain among adolescents and young adults. Obesity. 2014;22:2238-43.

7) Scientific Advisory Committee on Nutrition. Carbohydrates and Health. Norwich: The Stationery Office; 2015 

8) Guideline: Sugars intake for adults and children. Geneva: World Health Organization; 2015

9) Imamura F, et al. Consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review, meta-analysis, and estimation of population attributable fraction. BMJ. 2015;351:h3576.

10) Sheiham A, James WPT. Diet and dental caries - the pivotal role of free sugars reemphasized. J.Dental Research.2015. 94:1341–7.

Statistics and figures

WHO has several nutrition-related global databases. They include data for countries in the Region. Please click on the links to access them.

Vitamin and Mineral Nutrition Information System

WHO Global Database on Body Mass Index

WHO Global Database on Child Growth and Malnutrition

WHO Global Data Bank on Infant and Young Child Feeding

Some nutrition-related data from the Regional Health Observatory:

Estimates of anaemia in non-pregnant women of reproductive age

Anaemia in preschool-age children

Trend estimates for under 5 child malnutrition: