Three overweight children dubbed the 'sumo kids' have begun piling on the pounds more than ever after a botched weight loss operation in India.

Video shot earlier this month in Una, Gujarat, shows Yogita, six, Anisha, four, and Harsh Nandwana, three, at home with their parents.

The Nandwana children underwent a weight loss operation in Ahmedabad a year ago which at first helped them shed a couple of kilos each.

Rameshbhai Nandwana says his children's bellies are 'an abyss' and they are always hungry. Here his wife tends to their youngest daughter Harsh, who already weighs 20 kilos

But the siblings regained their weight and now weigh more than before the operation.

The children's father, Rameshbhai, said they were only able to have the operation because the government of Gujarat state 'buckled under media pressure' and agreed to fund it.

Now Mr Nandwana, 35, says he wants to sell his kidney in order to fund a better operation which he hopes will save his children.

Anisha's mother Pragna feeds her. Mr Nandwana is a labourer who has to work overcome to afford all the food his children eat

After the operation Yogita's weight was reduced to 33kg from 36kg, while her sister Anisha shed 4kgs from 47kg. Their younger brother Harsh, who weighed 16kg before operations, lost 2kilos.

But since then they have been piling on the pounds at an even greater rate.

Yogita weighs 37kg, Anisha clocks 56kg and Harsh weighs 20kg.

Yogita takes to the scales. Her weight came down from 36 to 33 kilos after the operation last year but it has crept up again since

Mr Nandwana, a labourer, said: 'The operation has done little good to my kids. If they continue to putting on weight like this, they won't be able to move an inch in coming days.

'I cannot see them dying in front of my eyes, so I will do whatever deems fit to take them to the right medical treatment.

'If that requires me to sell my kidney, I won't hesitate doing so.'

It is thought the children may be suffering from Prader-Willi syndrome, which leads to a constant hunger

He said: 'Their belly is an abyss. It is hard to be sure that their well-fed and their hunger is satiated. The kids demand food all the time and if there is any delay they start crying and screaming.

'The kitchen has become my living room now. At times, I get frustrated but then I console myself it is not the kids' fault. That they are suffering more than I do.'

He said: 'I work overtime in fields, dig wells, and do whatever menial job comes my way just to ensure that the kids are not hungry.

The children eat five times and consume dozens of chapatis during a normal week

Strangely the Nandwanas have an older daughter, Bhavika, who is seven and weighs a perfectly normal 17kg,

He said: 'I work overtime in fields, dig wells, and do whatever menial job comes my way just to ensure that the kids are not hungry.'

It is not clear what lies behind the children's condition but last year Dr Akshay Mandavia, a paediatrician at Mandavia Children's Hospital in Gujarat, said: ‘Their condition could be due to endocrinal disease or Prader-Willi syndrome.'