Judge Gillian Ellis ruled that the young people should be moved to long-term foster care under a care order, in a decision made last year.
She said: “I am satisfied that it is in the children’s welfare interests for these orders to be made, that these children need the chance to learn ways of living more healthily, and to improve their health by losing weight.”
Details of the case were revealed after the ruling was published online yesterday.
The judge said there had been ‘numerous interventions’ by the local authority, many of which had led to short-term improvements, but these had not been sustained and the young people had continued to gain weight.
Social services had provided Fitbits and had paid for gym membership, and the family was supposed to attend Weight Watchers.
But the judge said recordings from the Fitbits had not been provided as required and that their attendance at Weight Watchers was ‘inconsistent’.
She said the young people had ‘clearly had some very good parenting, as they were polite, bright, and engaging’ but said the parents ‘did not seem to understand the seriousness’ of the Local Authority concerns and failed to set boundaries or promote healthy eating and exercise.
She said: “Everyone agrees that this is a very sad and unusual case, of a loving family, where the parents meet many of the basic needs of the children, but the Local Authority has been concerned that the parents are not meeting the children’s health needs, in that both children are severely overweight, and the parents have shown an inability to help the children manage this condition.
“There are concerns too about the children’s self-care, and the impact on their self-confidence and social relationships of these conditions.”
The judge said there were also concerns about poor home conditions and a lack of guidance on personal care.
A West Sussex County Council spokesman said: “As the judge made clear, this is a sad and unusual case. We are unable to comment further on individual cases.
“The anonymity of young people involved in situations like this is vital for their wellbeing.
“We have a legal duty to protect all children who are at risk of suffering significant harm and always work to keep children with their families as far as is possible.
“Applying to a court for an order to provide further legal protection is a last resort.”