For well-meaning parents, selecting a diet that will help their child to avoid
becoming obese seems pretty straightforward: cut out the junk, pile on the
fruit and vegetables. Some gentle persuasion that low fat is good, coupled
with limited availability of crisps, chocolates and biscuits, should mean
children sail through adolescence without spare tyres.
And yet, parents’ paranoia about the thickening girths of the Play-Station
generation has reached fever pitch: more than a quarter of children in
English secondary schools are clinically obese, almost double that of a
decade ago. But experts are concerned that parents’ attempts to steer
children on to a virtuous dietary path can often backfire.
Last week, Dr John Kostyak and a team from the Pennsylvania State University
warned in the online magazine Nutrition Journal that so-called “muesli
mothers” are taking adult dietary messages to extremes and inflicting them
on their children. Of particular concern, Kostyak says, are very low-fat
diets consumed by an increasing number of children.
In their study, the Pennsylvania researchers found that children burn
considerably more body fat than adults relative to the amount of energy that
they use. By cutting out good fats – such as olive oil and sunflower oil –
parents are effectively putting their child’s natural development in
jeopardy. “Sufficient fat must be included in the diet for children to
support normal growth and development,” Kostyak says.
Rachel Cooke, a spokeswoman for the British Dietetic Association, says that a
healthy diet should consist of about 30 per cent fats, mainly unsaturated
from plant sources, and that getting less “might mean that children miss out
on vital nutrients, essential fatty acids and fat-soluble vitamins A, D and
E that are vital for good health”.
There are also other, less obvious, risks of limiting fat intake. As unlikely
as it seems, it could eventually make children fatter than those who gorge
on calorie-dense snacks.
This month Canadian researchers produced findings in the journal Obesity that
suggest that low-fat diets are not beneficial for children. In a study of
rats, the sociologist Dr David Pierce, from the University of Alberta’s
Institute of Human Nutrition, found that diet foods can distort the
connection that the brain makes between taste and calorie content. In
experiments, Pierce and his colleagues showed how the animals learnt to
associate the flavour of a food with the amount of energy it provides. When
juvenile and adolescent rats were fed sweet or salty low-calorie foods over
time, the younger animals later overate when fed similar-tasting
calorie-dense foods.
The findings suggested that the diet foods distorted the younger rats’ ability
to recognise calories and to regulate energy intake. Older, adolescent rats
seemed unaffected, probably because they did not rely on taste-related cues.
Pierce says his rat studies may provide important clues about how early
taste conditioning can lead to overeating and obesity. “Our results indicate
that in young children, diet foods may be a poor substitute for healthy
foods with sufficient calories to meet energy needs,” he says. “The use of
diet food and drinks from an early age into adulthood may induce overeating
and gradual weight gain.”
Cooke says that, while more work needs to be done to prove that the effect
holds true in young humans, it is the latest in a glut of emerging evidence
that parents have a huge influence on altering instinctive food choices in
their child’s early years. Babies are born with an innate preference for
sweet and salty foods and with internal hunger cues that send satiety
signals to the brain. It is social and environmental influences that shape
the individual food preferences we develop by adolescence and adulthood, but
none more so, it seems, than those in a child’s own home.
A study published a few months ago by researchers from the University of
Sheffield discovered, for instance, that parents who restrict their child’s
food intake in the belief that they are instilling healthy-eating parameters
could be misguided.
Reporting in the Journal of Public Health, Dr Elizabeth Goyder and her
colleagues at the School of Health and Related Research reviewed 26 studies
analysing how parents feed their children and attempt to control their
diets. Common practices, such as limiting snack foods and openly encouraging
children to eat more nutritious foods, were more likely to contribute to
weight gain than to prevent it.
What seems to happen when children are exposed to this sort of parental
behaviour, says Goyder, is that internal hunger cues become confused.
Pressure to eat certain foods and to avoid others leads to “uninhibited
eating and weight gain, particularly among girls” as they eventually fail to
recognise satiety.
“Children should be allowed to learn to regulate their own food intake by
responding to their internal hunger and satiety cues,” Goyder says. “This
can seem counterintuitive to some parents, especially those who want to
oversee what their children eat, but otherwise there can be psychological
and physical consequences.” No food, says Cooke, should be banned unless it
places a child at medical risk. “As a dietician, I have seen countless cases
of children who are banned from eating certain foods at home, only to
develop an obsession about them when they are with their friends or at
school,” she says.
“What and how much children eat is the result of a complex interplay of
learnt, innate and environmental factors. Keeping them healthy is not as
simple as cutting something out.”
Neither does it come down to parental coaxing to “eat up” what is on their
plate. In fact, parents who do try the gentle art of persuasion to encourage
healthy eating could unwittingly be encouraging weight gain. Dr Julie Lumeng
and Lori Burke, of the University of Michigan, videoed and evaluated the
eating patterns of four different foods by 21 mother and child pairs. They
counted how many times a mother prompted her son or daughter to eat and
found that, on average, the children complied with those prompts two-thirds
of the time. While obese or overweight mothers did not prompt more often,
their children were more likely to respond by eating (67 per cent of the
time) than the offspring of nonobese mothers, who complied with 52 per cent
of prompts to eat.
“A growing body of evidence suggests that maternal feeding behaviours are
related to childhood obesity risk,” says Lumeng. “Prompting may cause a
child to eat more even when full, therefore teaching them to ignore internal
hunger cues.” Quite how difficult it is for a parent to instil healthy
eating habits was outlined in a paper compiled for the British Nutrition
Foundation by Lucy Cooke, a researcher at University College London’s Health
Behaviour Unit. Promising children a reward for eating – eat up your peas
and you can watch TV – has been shown to decrease their liking for it.
Likewise, says Rachel Cooke, telling a child something is good for them
“should be avoided, as a ‘healthy label’ appears to imply a negative image”.
When a group of 40 nine to 11-year-olds was offered an unfamiliar drink,
those who were told it was a “new health drink” were less likely to admit
liking it than those told it was a “new drink”.
So what is a parent to do? Cooke says parents should remember that they act as
role models and that children are more likely to do as they do than to act
on what they say. “Their own eating habits are enormously influential,” she
says. “It is also important to realise that repeated exposure to certain
foods can increase acceptance, so don’t give up. Children need as wide a
variety of foods as possible.”
Crucially, though, parents should not be overcontrolling or obsessive. “If you
restrict what children eat, you are likely to do more harm than good,”
Goyder says. “They lose their ability to determine when they are really
hungry, which can lead to them eating too much. It is better to provide
reasonably healthy foods, a few snacks and then leave them to their own
devices.”
How to feed your children
1 Don’t restrict fat intake to below 30 per cent of a child’s diet.
Children need fat for growth and development. This is especially important
for the under5s, who should not be given semi-skimmed or skimmed milk or any
other low-fat version of a food.
2 Don’t ban any foods – even seemingly unhealthy ones. It can trigger
extreme eating habits, encouraging uninhibited eating which leads to weight
gain.
3 Allow children to follow their natural appetites when deciding how
much or how little to eat.
4 Set a good example. If you want children to eat more fruit and
vegetables, make sure you are seen doing the same.
5 Don’t instil the idea that there are “good” and “bad” foods. Inducing
guilt about diet can lead to eating problems including anorexia nervosa or
overeating, studies have shown.
6 Encourage children to eat as wide a variety of foods as possible to
ensure that they become accustomed to different tastes, textures and
flavours.
