Obesity warning for parents after study finds toddlers 'consume four times too much protein on average'

Infants aged one need less than 10g of protein per day, but those who took part in the study were consuming 40g on average

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The Independent Online

Toddlers are consuming more than four times as much protein than they need to, a new study has found.

Parents have been warned to watch their children’s intake of meat, cheese and milk after researchers linked protein-rich diets to higher levels of body fat.

Dutch researchers examined how much protein 3,564 one-year-olds were eating, both from animal and non-animal sources such as grains, cereals and soy.

Infants aged one need less than 10g of protein per day, but those who took part in the study were consuming 40g on average, said Dr Trudy Voortman, of the Erasmus University Medical Centre in Rotterdam.

A 300ml container of milkshake contains around 11g of protein. There is 5g of protein in one mini Babybel cheese, and around 9g in three chicken nuggets.

The children were weighed and measured eight times from the age of one to 10. They also had their body fat and other body mass analysed using a specialist piece of medical equipment called a dual x-ray absorptiometry scanner when they were were aged six and 10.

The study found that those in the top fifth for protein intake at the age of one were 1kg heavier by age 10, compared with those in the bottom fifth.

All of this extra weight was purely fat, rather than other body mass such as muscles or bones.

Dr Voortman said children in the Netherlands, and in other countries with similar diets including Britain, are “generally getting way more [protein] than they need”.

“A lot of parents see giving children lots of protein as a healthy thing to do, but this may not be the case. Our study showed that protein is contributing to purely fat mass.”

Why Swiss cheese has holes

She said protein from animal sources had the greatest effect on levels of body fat, adding it was not just a case of children being given too much milk, with other protein sources such as cheese, yoghurt, meat and fish all adding up.

Around one in five British 10- and 11-year-olds and nearly one in ten four- and five-year-olds are obese, according to figures from the National Child Measurement Programme.

Mary Fewtrell, professor of paediatric nutrition at UCL not involved in the study, told The Independent the issue of protein intake in infants is "quite a hot topic".

"There is increasing evidence that high protein intakes in this age group are associated with more rapid growth and [obesity] later on – also that animal protein (in some cases dairy more than other animal protein) is more strongly implicated than plant protein," she said.

The researchers, who presented their study at the European Congress on Obesity in Porto, Portugal, also looked at total food intake from other food groups, including carbohydrates and fats.

They found high-protein diets were associated with high levels of body fat regardless of whether protein was replacing carbohydrates or fats in the diet.

“Breast milk is quite low in protein and there are higher amounts in formula, although there are efforts to reduce protein levels in formula,” said Dr Voortman.

“People also use follow-on formula milks and, compared to regular milk they are okay for protein, but the simple fact is that children simply don't need that much. The overall message to parents is don't overrate protein.”

This pattern also tends to continue through childhood, she said, with older children also given too much protein.

While adults generally see protein as healthy, early childhood could be seen as a “risk window” in which a high protein intake may not be beneficial, Dr Voortman told The Independent.

“Protein from animal sources can trigger the release of insulin and other growth factors, which specifically results in body fat,” she said, adding more research is needed to discern exactly why this effect takes place.

Dr Ian Johnson, nutrition researcher at the Quadram Institute Bioscience in Norwich, said the study has “very interesting” and should be taken seriously as it was “conducted on a large number of infants in a prosperous western population, using robust methods”.

However, he said it was too soon to make recommendations to parents about their children’s diets.

Russell Viner, officer for health promotion at the Royal College for Paediatrics and Child Health, and Professor in Adolescent Health at University College London (UCL), said the study “supports the long-held view that diets high in protein are unlikely to be effective for weight loss in children.”

“We know that the slow drip of day-to-day calorie intake excess results in the increased likelihood of childhood obesity,” he said.  

“This research is particularly interesting because it shows that having a high animal protein diet in early childhood doesn’t necessarily lead to stronger muscles and bones later on, providing yet more evidence of the importance of a balanced diet for children.”

Dr Voortman said she did not recommend parents feed their children a vegan diet, which is “too extreme”, but should watch out for products labelled low-fat that are actually high in protein.

“Perhaps have a little bit of high fat yogurt, instead of a lot of low-fat yogurt.”

“We know that typical protein intakes in European infants and toddlers are often significantly higher than their requirements,” said Professor Fewtrell.

“Of course we also have to remember that there are many infants in the world (and probably groups in Europe) who still don't get enough protein from high quality sources, so we obviously need to target our advice appropriately and consider the infant or child's whole diet.”