Kelly Jallow, from Ince, was "fuming" when she received a letter from council partners, Inspiring Healthy Lifestyles, to tell her that her daughter had been categorised as overweight in her reception class weigh-in.
The despairing mum whose daughter. Mariama, attends Brittania Bridge Primary School, now fears it will give her a complex about her weight.
"To me and to everyone else, she looks fine," said Kelly. "I just started crying when I saw the letter, I was fuming.
"I do everything I can for my daughter. She has a strict diet. When I opened that and saw it I was really upset.
"I just don’t understand how they can say my daughter is overweight. I don’t give her junk food and she’s really active, she never sits still."
The letter explains that at 107.9cm and weighing in at 21kg, Mariama’s BMI is indicating that she is overweight.
It reads: "These results suggest that your child could possible face a range of health problems which could be avoided by making positive changes now to be more active and eat healthily."
Kelly said that she has even been offered to send her daughter on a "healthy lifestyle" camp to stop her from putting on more weight.
"That’s a nice way of saying a weight camp. Mariama gets upset when you say the word fat.
"If she asks for sweets and I tell her they can make you fat, she gets upset. It’s really putting them, and parents, under pressure and it makes me look like the worst mum in the world.
"I’m a single parent and I’m trying everything I can to do the best for her. She sees her dad twice a month and I’ve told him about it and he’s shocked. Everyone is shocked.
"If she loses any weight she could end up anorexic and then they would have a moan about that as well."
Prof Kate Ardern, director of public health, said: "We are extremely sorry if the measurement has caused upset to Mariama and her family. We understand their frustration but would like to assure residents that the programme is designed to help improve child health in Wigan Borough and to ensure every child has the best possible start.
"We measure every child’s height and weight based on national indicators, which then determines whether a child is underweight, a healthy weight or overweight for their age, sex and height.
"We want to work with families to ensure they have access to any extra support they may need, so once the measurement has been taken, we issue letters to parents to make them aware.
"If parents wish for the measurement to be retaken with them present or would like any further information about how the measurement is taken, Inspiring Healthy Lifestyles can speak with the families directly.
"The National Child Measurement Programme is one part of the local health and wellbeing offer, which also includes other targeted programmes such as; a supervised tooth brushing scheme, the roll out of The Daily Mile and a specialist weight management programme for those children and families that require further support."