Portion sizes ‘have sustained effect’ on children – research

New research suggests that young children are less able to self-regulate their consumption in the face of larger portion sizes than previously thought.

Scientists from Pennsylvania State University conducted a study among preschool children aged between three and five years old. A total of 46 children were served the same five daily menus over two periods – first, they were served a baseline portion; then, in the other period, all the portions were increased by 50%.

The results indicate that increasing the portion size led to higher levels of consumption by both weight and energy.

The researchers wrote that “trajectories of intake by weight and energy across the five-day period were linear and the slopes did not differ between portion conditions, indicating that there were sustained increases in intake from larger portions without compensatory changes over time”.

The research suggests that previous thinking about childhood food intake – that young children will self-regulate their consumption until they have simply had enough food, when confronted with excessively large portion sizes – could be wrong.

In their conclusion, the researchers wrote: “This demonstration that preschool children failed to adjust their intake during prolonged exposure to larger portions challenges the suggestion that their self-regulatory behaviour is sufficient to counter perturbations in energy intake. Furthermore, overconsumption from large portions may play a role in the development of overweight and obesity, as the magnitude of the effect was greater in children of higher weight status.”

The study, published in The American Journal of Clinical Nutrition, may have wider implications on approaches to tackling childhood obesity.

According to the World Health Organization, 41 million children under the age of five, as well as more than 340 million children and adolescents between the ages of five and 19, were either overweight or obese in 2016. More than half of the world’s population lives in countries where deaths related to obesity are more prevalent than deaths related to malnutrition, as unhealthy and junk-ridden diets become increasingly commonplace – particularly in affluent and up-and-coming economies.

In the US, the percentage of children and adolescents affected by obesity has more than tripled since the 1970s, according to the Center for Disease Control and Prevention. Nearly one in five school-aged children and young people in the US are obese, according to data from the National Health and Nutrition Examination Survey, representing a potential 10 million children.