The brain consumes half of a child's energy -- and that could matter for weight gain

New paper proposes that variation in brain energy expenditure during childhood could be linked to obesity risk

June 17, 2019

Science Daily/Northwestern University

Weight gain occurs when an individual's energy intake exceeds their energy expenditure -- in other words, when calories in exceed calories out. What is less well understood is the fact that, on average, nearly half of the body's energy is used by the brain during early childhood.

In a new paper published in the journal Proceedings of the National Academy of Sciences (PNAS), "A hypothesis linking the energy demand of the brain to obesity risk," co-authors Christopher Kuzawa of Northwestern University and Clancy Blair of New York University School of Medicine, propose that variation in the energy needs of brain development across kids -- in terms of the timing, intensity and duration of energy use -- could 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," said Kuzawa, professor of anthropology in the Weinberg College of Arts and Sciences and a faculty fellow with the Institute for Policy Research at Northwestern. "When kids are 5, 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."

"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."

According to the authors, another important unknown is whether programs designed to stimulate brain development through enrichment, such as preschool programs like Head Start, might influence the brain's pattern of energy use.

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

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 showed 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.

https://www.sciencedaily.com/releases/2019/06/190617164629.htm

Strength-based exercises could help child obesity fight

September 19, 2018

Science Daily/University of Edinburgh

Encouraging young people to do strength-based exercises -- such as squats, push ups and lunges -- could play a key role in tackling child obesity, research suggests.

Taking part in exercises that cause muscles to contract, and strengthen muscles and bones, was found to reduce children's body fat percentage.

The findings also suggests an increase in muscle mass -- gained from strength-based exercises -- could help boost children's metabolism and energy levels.

The effects were small but meaningful, prompting calls for further research to investigate how resistance training could treat and prevent the growing issue of child obesity.

Researchers at the Universities of Edinburgh and Dundee examined the findings from a number of studies that explored effects of resistance training on body weight for children aged nine to 18 years.

They found that resistance training decreased body fat, but had no overall effect on other measures, including lean muscle mass, body mass index and waist circumference.

This is the most extensive review so far of resistance training's impact on young people.

Research from 18 studies across eight countries was examined, including the US, Australia, and Japan.

Helen Collins, a PhD student at the University of Edinburgh and Sport and Exercise Scientist at the University of Dundee, said the results show the positive effect resistance training can have on maintaining a healthy weight and reducing body fat for young people.

"Treatment, and more importantly, prevention, of child obesity is a growing concern. Our findings highlight the need for more robust research into the role strength-based exercises can play in helping everyone make healthy life choices and be more physically active."

https://www.sciencedaily.com/releases/2018/09/180919083145.htm