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A ban on pupils having sugar in their cups of tea at a school canteen has been lifted - in favour of a "two sugars" rule.
Sixth-formers at Tonypandy Community College had protested at the ban and were supported by their head teacher.
Now pupils have been told they can take sugar - providing it is not more than two spoonfuls.
Earlier, Rhondda Cynon Taf Council said it was following guidance but pupils could add their own sweeteners. <!-- E SF -->
This is the latest issue over healthy food guidance to come to light at Welsh schools in recent weeks.
Bought-in tomato ketchup is off the menu at Vale of Glamorgan primary schools while Marmite is banned from Ceredigion's school breakfast clubs due to worries over salt content.
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Prohibiting certain foods and drinks to young people will only make them more determined to buy them through some other means 
Student Council letter to the Rhondda Leader
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Students at the secondary school in Tonypandy, Rhondda, had spoken of being "amazed" at being told they couldn't have any sugar in tea.
"If you were told that at a local cafe you would walk out in disgust," said one.
Pupils had threatened to boycott the canteen and go to local cafes instead.
Head teacher Stephen Parry said there had already been a sharp decline in pupils having school meals since healthier food was introduced.
Emma-Jayne Morgan, 16, chair of the student council, wrote to the
Rhondda Leader on behalf of a group of sixth-formers to raise students' concerns and is supported by the school's head teacher.
"I know of several parents whose children refuse to stay in school for lunch, and many of these parents will not let their children eat school meals," she wrote.
"This is not the way to tackle obesity and health problems.
"Prohibiting certain foods and drinks to young people will only make them more determined to buy them through some other means."
Head teacher Mr Parry had said he was concerned about increasing restrictions on what can be served in school canteens under the assembly government's healthy schools agenda.
Mr Parry said banning sugar in tea had not been his decision and meals were provided by a catering company through Rhondda Cynon Taf council.
A spokesman for the council said earlier: "We can confirm that the council is complying with Welsh assembly government regulations on nutrition and healthy eating.
"Whilst the regulations are not currently legislature, like many other Welsh councils, Rhondda Cynon Taf is endeavouring to comply with what has been set out. One of the aims outlined is to reduce salt, sugar and increase fibre.
"As a consequence the council no longer adds sugar to the drinks served, however this does not stop an individual adding sweeteners or sugar at a later stage if they require it."
A Welsh Assembly Government spokesperson said: "In our appetite for life action plan we recommend no sugar in tea and coffee.
"This is currently guidance and not compulsory and the practicalities of adhering to this, and other recommendations will be tested through our action research project.
"Local authorities and schools may decide to introduce the recommendations as part of their whole-school approach to improving their pupils health and well being. "However, introducing any change effectively requires schools to work closely with all their key stakeholders which includes pupils."
