The brain consumes half the energy of a child, which can contribute to weight gain

Weight gain occurs when the energy intake of an individual exceeds his energy expenditure, in other words, when the number of calories absorbed is higher. What is less well understood, it is that on average, nearly half of the body's energy is used by the brain during infancy.

In a new article published in the journal Proceedings of the National Academy of Sciences (PNAS), "An Assumption Connecting the Energy Demand of the Brain to the Risk of Obesity," Christopher Kuzawa, co-author of Northwestern University, and Clancy Blair, of the Faculty of Medicine at the University of Michigan. 39, New York University, suggest that the variation in energy requirements of brain development among children's terms of duration, intensity and duration of energy use – could affect patterns of energy expenditure and gain weight.

"We all know that the amount of energy that our body burns significantly influences weight gain," said Kuzawa, professor of anthropology at the Weinberg College of Arts and Sciences and a faculty member at the University of Ottawa. Institute for Policy Research of Northwestern. "When children are 5 years old, their brains use almost half of their body's energy, yet we do not know how much brain energy expenditure varies among children." a huge hole in our understanding of energy expenditure. "

"One of the main goals of our paper is to draw attention to this understanding gap and to encourage researchers to measure brain energy consumption in the future." studies on child development, especially those focused on understanding weight gain and the risk of obesity. "

According to the authors, another important unknown is whether programs designed to stimulate brain development through an enrichment, such as preschool programs such as Head Start, could influence the energy consumption pattern of the brain.

"We think it's plausible that an increase in brain energy expenditure may be an unexpected benefit for early childhood development programs, which, of course, have many other proven benefits," he said. kuzawa. "It would be a big win-win."

This new hypothesis was inspired by the 2014 study by Kuzawa and his colleagues, according to which the brain consumes a peak of its life accounting for two-thirds of the body's resting energy expenditure, and almost half of the total expense, when the children are five years old. This study also showed that ages where brain energy requirements increase during infancy are also ages of weight loss. As the energy required for brain development decreases in older children and adolescents, the rate of weight gain increases in parallel.

"This discovery confirmed a long-standing hypothesis in anthropology that human children would evolve much more slowly than other mammals and primates, in part because their brains needed more energy to develop," he says. said Kuzawa.

"A hypothesis linking the energy demand of the brain to the risk of obesity" will be published in the week of June 17 PNAS.