Susan Jebb, head of diet and obesity research at the Medical Research Council's Human Nutrition Research unit in Cambridge, said she did not see juice as a healthy option.
"I would support taking it out of the five-a-day guidance," she said.
"Fruit juice isn't the same as intact fruit and it has got as much sugar as many classical sugar drinks. It is also absorbed very fast so by the time it gets to your stomach your body doesn't know whether it's Coca-Cola or orange juice, frankly," she told Sunday Times.
Jebb said she had herself stopped drinking orange juice and advised others to do so, or at least drink it diluted.
More From This Section
The paper quoted her as saying she would support a wider tax on sugar-heavy drinks.
Jebb works closely with the UK government on diet and obesity issues, and leads the government's so-called health responsibility deal, which oversees voluntary pledges by the food and drink industry to improve public health.
Popkin, a professor of nutrition at the University of North Carolina, told the Guardian that fruit juices and fruit smoothies were "the new danger".
"Think of eating one orange or two and getting filled. Now think of drinking a smoothie with six oranges and two hours later it does not affect how much you eat. The entire literature shows that we feel full from drinking beverages like smoothies but it does not affect our overall food intake, whereas eating an orange does," he said.