Fruit juice has too much sugar and should not be one of our "five-a-day" health foods, according to research.
Academics at Bangor University in North Wales say their study showed that overweight and obese people have a "dulled" sensitivity to the drinks, but enhanced "subconscious liking" of the taste.
Hans-Peter Kubis, of the university's School of Sport, Health & Exercise Sciences, has called for sugar to be taxed to stop an impending health "disaster", and for fruit juice to be taken out of the "five-a-day" health message.
He said: "This research shows how little sweet foodstuffs are required to change your taste perceptions and how powerful sweet tasting products are. We are headed for a health disaster."
Researchers are encouraging parents to give their children water instead of fruit drinks.
Natural fruit juice, as well as carbonated drinks and cordials, are all "too high in sugar and too sweet", according to the findings.
Dr Kubis said: "My reaction would be to encourage the Government to consider taxing sugar that is added to foodstuffs - and have that tax ring-fenced for the health budget. Fruit juice is higher in sugars than people realise."
In the trial, lean and obese people were asked to rate their enjoyment of sweet and salty tastes. The trial showed that overweight participants rated drinks as being less sweet than lean participants. The conclusion was that the overweight participants had a "reduced sensitivity" to sweetness but an "enhanced subconscious preference" for sweet food. The study involved 33 people, 22 'normal' and 11 overweight people.
Richard Laming, of the British Soft Drinks Association, said: "It is wrong to draw sweeping conclusions from this experiment that involved only 12 subjects with no control group."
According to the NHS, one 150ml glass of unsweetened 100% fruit or vegetable juice can count as one "five-a-day" portion. But only one glass counts, further glasses of juice don't count toward your five portions. Five-a-Day is based on advice from the World Health Organisation, which recommends eating a minimum of 400g of fruit and vegetables a day.