If you feed fructose ad libitum to non-human primates, they get fatty livers within six weeks (American Journal of Clinical Nutrition 2013,doi:10.3945/ajcn.112.057331).
The effect of fructose rich beverages on human adolescents is a lot harder to judge, given that you cannot cage teenagers and feed them a controlled diet – however much you may sometimes wish to!
But in a Western Australian study in the American Journal of Clinical Nutrition (2013,doi:10.3945/ajcn.112.0511383), food diaries kept by 14 to 17 year olds showed a strong association between the consumption of fructose rich drinks and the risk of obesity and adverse cardiometabolic markers.
- High fructose corn syrup and obesity- what is the relation (myworldofmedicine.wordpress.com)
- High Fructose Diets and High Blood Pressure (healthylivingonline.co)