Sweet enough already?
Peter Wootton-Beard, Oxford Brookes University
Are sugar-sweetened soft drinks making us fatter?
Several recent high-profile reports have suggested that drinks that contain sugar contribute towards being overweight or obese [1, 2]. Our own National Diet and Nutrition Survey (NDNS) showed that 52% of us consumed carbonated soft drinks (not low calorie) and 22% of us consumed concentrated soft drinks. Furthermore, 42% of men and 24% of women drink tea with sugar and 46% of men and 27% of women drink coffee with sugar . We all know that sugar-sweetened drinks are not ‘good’ for us, but are they really BAD for us?
A review of the evidence published in The Nutrition Society’s journal ‘Nutrition Research Reviews’ is helping us to better understand the facts. Nutrition consultant and registered public health nutritionist Sigrid Gibson pulled together 44 studies to see if there really is any relationship between sugar-sweetened soft drinks and weight gain . Half of all the investigations mentioned in this review showed that sugar-sweetened soft drinks might lead to being overweight; the other half showed that there was no connection. They did not include tea and coffee.
The review highlighted some problems with this area of research:
- The majority of studies are conducted in children, which means we don’t know much about the effects on adults.
- A lot of the information comes from the USA where sugar-sweetened drink consumption in children is twice as high as it is in the UK. Also, USA data may not be relevant in Europe because of variations in the type of sugar used, for example there is a much higher consumption of high-fructose corn syrup.
- It is difficult to see if there is a causal relationship because lots of other factors contribute towards putting on weight.
- It is difficult to compare studies in this area because the definition of sugar-sweetened soft drinks varies. For example, some studies included diet soft drinks and fruit juice whilst others excluded these.
Despite these problems, some crucial information comes to light:
- Sugar-sweetened soft drinks contain energy but may contribute only small amounts of other nutrients. Energy is energy, If we take in more energy than we need, then we put on weight. It’s hard to say that sugary drinks cause obesity, but excess energy definitely does.
- Occasionally drinking sugar-sweetened soft drinks (1-2 times per week) is unlikely to cause any problems, but drinking them very frequently does, particularly if a person is already overweight.
- Avoiding consuming too many sugar-sweetened soft drinks is important for children. The habits we form in childhood can affect our future lifestyles. However, it is equally important for adults to be careful about letting poor dietary habits get out of control.
- When comparing food labels, the Department of Health suggests looking for those that are low in sugar which means foods and drinks containing less than 5g of total sugars per 100g; anything with over 15g per 100g is considered high in sugar.
- Consumers wishing to reduce their sugar intake should pay particular attention to the ‘traffic lights’ system on food labels, one section of this is often dedicated to sugar content.
- Being active, and eating a healthy diet which includes lots of fruit and vegetables is the most important message for most people.
1. World Health Organisation & Food and Agriculture Organisation (2003). Diet, Nutrition and the prevention of chronic diseases. Geneva: WHO.
2. World Cancer Research Fund (2007). Food, Nutrition, physical activity and the prevention of cancer. Washington DC: American institute of cancer research.
3. Henderson, L., Gregory, J., & Swan, G. (2002). The National Diet and Nutrition Survey: adults aged 19-64 years; Types and quantities of foods consumed. Vol 1. London, UK: HMSO. Available from: http://www.food.gov.uk/multimedia/pdfs/ndnsprintedreport.pdf (accessed 20 February 2012).
4. Gibson, S. (2008). Sugar-sweetened soft drinks and obesity: a systematic review of the evidence from observational studies and interventions. Nutrition Research Reviews, 21, 134-147.
Source: The Nutrition Society