Childhood obesity is a serious health issue and an early risk factor for obesity in adulthood, leading to morbidity and mortality. The odds ratio of obese toddlers is 1.3 for becoming obese adults, but increases to 17.5 in adolescents. Those who remain obese in adulthood are prone to a cluster of diseases and disorders called metabolic syndrome (MetSy).[1] Worldwide, this syndrome is present in 20-25% of the population, while in Australia it is estimated to affect 1 in 3 adults.[2]

However, there is a lack of empirical data linking MetSy reduction with weight management alone. Therefore, a 2016 analysis of a large cross-section of US adolescents looked at another lifestyle factor and found it to be significantly associated with MetSy, independent of body mass index (BMI) scores. This alternative factor was added sugar intake.[3]

Using data from the US National Health and Nutrition Examination Survey (NHANES) between 2005 and 2012, researchers analysed the link between added sugar intake and MetSy in 1623 adolescents. The sugar intake was calculated from 24-hour dietary recall questionnaires. They also evaluated BMI, physical activity, total daily kilocalorie intake and analysed biomarkers of MetSy, including:[3]

  • fasting triglycerides (TG)
  • blood glucose and insulin
  • HDL cholesterol (HDL-C)
  • uric acid
  • alanine aminotransferase (ALT), as substitute for NAFLD • TG:HDL-C (an indicator of insulin resistance)
  • blood pressure.

The results showed that the prevalence of MetSy in US adolescents was 5.4% overall, with the mean added sugar intake for this age group at 94 grams per day, the rough equivalent of 23 teaspoons.[3,4] The level of daily sugar intake correlated directly with the prevalence of MetSy. Those with the highest level of added sugar in their diet (112-186 grams per day) had an 8.4% prevalence of MetSy. When adjusting individual MetSy components, the higher sugar groups (81.8-186 grams) had significantly increased levels of TG and insulin, with depressed HDL-C. Sugar intake did not seem
to affect ALT levels in this population. Additionally, the study results found that added sugar intake was directly associated with MetSy, independent of total energy intake, physical activity or BMI scores.[3]

The American Heart Association recently reviewed the evidence for the effect of sugar in children’s diets. Their final recommendation was that “children consume ≤25g (100 cal or ≈ 6 teaspoons) of added sugars per day and to avoid added sugars for children <2 years of age”.[5]

Prof. Robert Lustig, a paediatric endocrinologist who specialises in neuroendocrinology and childhood obesity, recommends rethinking sugar as a condiment not a staple food, keeping it out of drinks and non-dessert food, and reducing the amount used in desserts.[6]


  1. Weiss R, Bremer AA, Lustig RH. What is metabolic syndrome, and why are children getting it? Ann N Y Acad Sci 2013;1281:123-140. [Full text]
  2. My VMC. Metabolic syndrome, 2008. Viewed 5 January 2017. [Link]
  3. Rodríguez LA, Madsen KA, Cotterman C, et al. Added sugar intake and metabolic syndrome in US adolescents: cross-sectional analysis of the National Health and Nutrition Examination Survey 2005-2012. Public Health Nutr 2016;19(13):2424-2434. [Abstract]
  4. Rellinger D. How to convert grams of sugars into teaspoons, 2013. Viewed 5 January 2017. [Link
  5. Vos MB, Kaar JL, Welsh JA, et al. Added sugars and cardiovascular disease risk in children. A scientific statement from the American Heart Association. Circulation 2016;134:00-00. [PDF]
  6. Lustig RH. A condiment, not a diet staple. Viewed 5 January 2017. [Link


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