Parents should stop giving their children fruit juice at breakfast because it significantly increases their chances of being overweight or obese, a study has found.
Those who drank a glass in the morning were one-and-a-half times more likely to be overweight than those who did not.
Skipping breakfast was also linked to weight gain as it made children more likely to snack during the day, according to researchers.
Though fruit juices are frequently marketed as a healthy choice, they are often high in sugar and calories.
Previous research has shown a 350ml glass can contain up to nine teaspoons of sugar and is not as nutritious as unprocessed fruit.
The study, led by the Medical University of Vienna, looked at the breakfast habits of 650 children and compared them to their weight and height.
Some 29 per cent were classed as overweight or obese on the body mass index.
Those who drank water at breakfast were 40 per cent less likely to be overweight, it found.
Only four in ten children under the age of 13 ate breakfast every day, with around a third eating it fewer than five times a week and a similar proportion skipping it.
The study found that those who did eat breakfast were three pounds lighter on average than those who skipped it.
Speaking at the world’s biggest obesity conference in Vienna, lead researcher Dr Maria Luger urged parents to reduce children’s sugar consumption at breakfast.
She said: ‘It’s very important to get a lot of fibre. So eat an apple or an orange instead of drinking fruit juice.
Drink water or unsweetened tea and, if you drink fruit juice, add water.’
Nearly half a million under-11s are now obese. Experts have warned this will result in higher rates of Type 2 diabetes, heart disease and cancer in the decades to come.
Public Health England recently found that children are eating three times too much sugar – half of which comes from unhealthy snacks and sugary drinks.
Jason Halford, of the European Association for the Study of Obesity, said: ‘Fruit juice is not entirely bad but in terms of appetite it is not as filling as whole fruit and has the fibre removed and consequently [it is] a concentrated form of sugar.’
Dr Carrie Ruxton, of the British Fruit Juice Association, said: ‘A daily 150ml glass of pure fruit juice, the portion size recommended by Public Health England, helps children to meet dietary targets for fruits and vegetables and is an important source of vitamin C, folate and potassium.’