Varying brain energy expenditure in childhood associated with weight gain: Study

It is well known that we tend to put on weight when we consume more calories than we spend. It is, however, less known that our brain uses half of the body's energy during early childhood.

Research published in the journal of 'Proceedings of the National Academy of Sciences' says that variation in the energy needs of brain development across kids -- in terms of the timing, intensity, and duration of energy use -- can influence patterns of energy expenditure and weight gain.

"We all know that how much energy our bodies burn is an important influence on weight gain. When kids are five, their brains use almost half of their bodies' energy. And yet, we have no idea how much the brain's energy expenditure varies between kids. This is a huge hole in our understanding of energy expenditure," said Christopher Kuzawa, co-author of the study.

"A major aim of our paper is to bring attention to this gap in understanding and to encourage researchers to measure the brain's energy use in future studies of child development especially those focused on understanding weight gain and obesity risk."

"We believe it is plausible that increased energy expenditure by the brain could be an unanticipated benefit to early child development programmes, which, of course, have many other demonstrated benefits. That would be a great win-win," Kuzawa said.

This new hypothesis was inspired by Kuzawa and his colleagues' 2014 study showing that the brain consumes a lifetime peak of two-thirds of the body's resting energy expenditure, and almost half of total expenditure when kids are five years old.

This study also shows that ages, when the brain's energy needs increase during early childhood, are also ages of declining weight gain. As the energy needed for brain development declines in older children and adolescents, the rate of weight gain increases in parallel.

"This finding helped confirm a long-standing hypothesis in anthropology that human children evolved a much slower rate of childhood growth compared to other mammals and primates in part because their brains required more energy to develop," Kuzawa said.