No assessment has been made specifically of the link between high-cost, low-volume sugary drinks and levels of obesity. However, in July 2015 the Scientific Advisory Committee on Nutrition (SACN) published its report on Carbohydrates and Health which considers the relationship between the intake of sugars-sweetened drinks and weight gain.
Evidence from randomised controlled trials conducted in children and adolescents indicate that consumption of sugars-sweetened drinks, compared with non-calorically sweetened drinks, results in greater weight gain and increases in body mass index. This finding suggests that there is inadequate reduction in energy from other foods or drinks to compensate for energy delivered as sugars.
SACN recommended that consumption of sugars-sweetened beverages should be minimised in children and adults.
The SACN report on Carbohydrates and Health is available to view here: