The government looks set to come under pressure to stop schools installing fizzy drinks machines on their premises.
One in five children has 10 fizzy drinks a week
Doctors attending the British Medical Association conference in Torquay are expected to call for a review of the policy later on Tuesday.
They will say that the machines encourage children to drink large quantities of fizzy drinks.
Studies have shown that too many fizzy drinks can affect children's concentration and can also disrupt their sleep.
Doctors are also concerned that they are contributing to the rise in obesity in children across the UK.
Dr Tom Yerburgh, a GP in Gloucestershire, will call on the government to review the policy.
I am concerned that having these machines in schools reinforces the view that fizzy drinks are ok
"I want the Department of Health to discuss the desirability of these machines with the Department for Education," he told BBC News Online.
"Research has shown that fizzy drinks, particularly those with caffeine, can cause hyperactivity in children.
"They also affect their concentration and sleep patterns.
"Studies have suggested that one in five children drinks 10 cans of fizzy drinks each week.
"I am concerned that having these machines in schools reinforces the view that fizzy drinks are ok."
Many schools install drinks machines as a way of supplementing their income. They receive a share of the profits from sales.
To some schools, the machines are worth as much as £10,000 a year.
Dr Yerburgh will also call on the government to take steps to ensure that schools make drinking water more widely available to students.
"Schools need to do more. There are not enough drinking fountains in schools.
"This is not good enough. Dehydration is also known to have an adverse effect on children's concentration. It is a problem."
The second day of the BMA conference is expected to be dominated by a debate on the consultants contract.
Consultants have been threatening to take industrial action over the government's refusal to re-open talks on their contract, which was rejected last year.
John Reid, the new health secretary, initially ruled out fresh talks with the BMA.
However, he now looks set to try to resolve the deadlock after saying at the weekend that he would now hold discussions.
Consultants have been pressing for fresh talks for over seven months. The BMA is understood to have been taking steps towards holding a nationwide ballot of consultants in preparation for industrial action later this year.
If it goes ahead, it will be the first industrial action by doctors in almost 30 years.