Ava Carvey has Prader-Willi syndrome (PWS) which leaves her constantly hungry meaning the family kitchen has to be kept behind bars.
Her mother, Marika Carvey, 35, has to keep Ava on a strict low calorie diet to prevent her overeating.
Mrs Carvey, from Bromley, said: ‘If Ava had access to the food, she would eat whatever she could lay her hands on.
‘She's not just permanently hungry - she's ravenous. If there's food on the floor, she'll pick it up and eat it, and if someone else has food she wants theirs too. She'll even take food away and hide it.
‘It's scary because if we didn't watch her she'd eat until her she made herself sick.
‘When she gets older we will have to put locks on the fridge and cupboards too.
‘She's such a lovely little girl and sometimes I feel so sorry for her - imagine always feeling like you're starving.
‘It must be horrible but she's always got a smile on her face, she's always running about enjoying herself just like any other five-year-old.’
Ava was diagnosed with the genetic condition at just nine-weeks-old after doctors noticed she was failing to feed and move around properly.
She gets so hungry that her mother must ensure her other children, Joshua, 11, and Finnian, two, never eat in front of her.Mrs Carvey said: ‘If Ava sees her brothers eating she'll try to take their food, so we have to make sure that if she's not eating, no-one else is.
‘PWS sufferers are prone to tantrums, so if we go out to eat we have to be very careful. I'll ask the waiters to give her a smaller portion, and as soon as we finish a meal at a restaurant, we have to leave immediately.
‘If she noticed other people's food she'd start getting upset - or try and eat the leftovers.
‘If we go to parties with a buffet it can be a bit of nightmare. She'll just stand by the table and eat whatever she wants on it. We have to watch her like a hawk and often have to leave if she doesn't get what she wants.’
PWS also means that sufferers don't burn energy as quickly as the average person, leading them to gain weight easily.
Mrs Carvey, therefore, has to ensure that Ava only eats healthy food as she could easily become obese.
She said: ‘Obesity is a common problem in children with PWS. Instead of sweets and biscuits, she has raisins and rice cakes for her treats.
‘I've never given her Easter eggs and on her birthday she has jelly instead of a cake.
‘She does have tantrums sometimes, especially if there's food around and she can't have it, but most of the time she's a really happy little girl.
‘We keep her busy between meals, and she's starting to understand that the PWS makes her hungry but doesn't stop her eating. She's doing really well.
‘Her brothers are really good with her too, especially Joshua as he's old enough to understand what PWS is about. Finnian isn't quite so sure though - I try and slip him a treat every now and then when Ava's not around.’
Mrs Carvey, and her husband Martyn, 32, were told about Ava's condition when she was just nine-weeks-old.
Mrs Carvey said: ‘The day after Ava was born it became clear that things weren't quite right.
‘She wasn't moving much and hadn't fed. I wasn't too worried but the doctors were looking at her a bit strangely and all of a sudden she was whisked off to special care.
WHAT IS PRADER-WILLI SYNDROME?
Prader-Willi syndrome is a rare genetic condition.
It causes a constant desire to eat, dangerous weight gain, restricted growth, reduced muscle tone, learning disabilities and behavioural problems.
It affects one in every 15,000 children born in the UK.
Children with the condition will eat three to six times more than other children and will still want more.
There is no cure but the condition itself is not life threatening.
However, people with the syndrome often develop obesity related conditions such as type 2 diabetes and heart failure.
‘The next thing I knew she was being transferred to St Thomas's Hospital in London for tests.
‘By this stage she wasn't moving at all - apart from her eyes - and she couldn't even cry. She still hadn't fed either, it was just awful.
‘We were in a ward where all these children were covered in tubes and we wondered if Ava was going to end up like that too.
‘The doctors were running test after test but we asked them not to tell us what they thought she had until they were certain.
‘We didn't want to start Googling all these medical conditions that she could have and worry ourselves needlessly.’
Nine weeks later Ava’s parents were finally told that she had been diagnosed with PWS.
Marika said: ‘I'd heard of the condition before because I know Katie Price's son has it, but I wasn't really sure what it involved.
‘They gave us some leaflets and told us about some groups we could join, but we asked if we could just have six months alone to get used to the idea.
‘We were lucky because we knew about Ava's PWS from a very young age, so she never got very big. We were able to control it.’
As Ava grows older, there is a concern that it will be harder to keep her PWS under control.
Mrs Carvey said: ‘The older she gets and the bigger she gets, it's going to be harder for me to stop her eating.
‘She's already quite a restless sleeper, so when she's older she could easily get out of bed in the middle of the night and eat anything she wanted.
‘I do worry that she'll form a bad relationship with food, and I'd hate for her worry about her body and things like that, but for now she's doing really well.
‘She's an adorable little girl, with a really happy, affectionate personality, and we love her to bits.’
A spokesman for the PWS Association said: ‘PWS is a genetic condition, usually not hereditary, which is present from birth and affects a person throughout their entire life.
‘Its main features are an almost constant feeling of hunger and consequent desire to eat, low muscle tone, short stature, immature sexual development, immature emotional and social development and, in most cases, learning disability.
‘Children with PWS have a much higher risk than other children of becoming obese at an early age because of two key factors: overeating and low muscle tone - the latter meaning that they do not burn up energy as fast as other children.
‘They also have more fat mass and less lean body mass than other children. Muscle burns more energy than fat, so again there is less burning up of energy in PWS.
‘While growth hormone treatment is now helping many children with PWS increase their height and muscle strength, parents must still put controls in place to prevent their children from eating and provide a lower calorie diet to enable their child to maintain a healthy weight.
Source: UKDaily Mail