Lyndsay was furious about the effect this had on Olivia - who she claims was so shaken that she refused to eat for two days.
Olivia said: "I feel quite annoyed about it because it isn't that accurate and it's not that nice, I just felt really bad because I read the letter and was basically being called overweight by the NHS."
Mum Lyndsay said: "It is unbelievable how much damage can be done by this programme.
"We never eat processed foods as I am always really careful of our diets, having a background in nutrition."
Now she has spoken out against the National Child Measurement Programme (NCMP), the programme used at the school which aims to monitor obesity in children.
She said: "They never bothered to investigate what my background was, despite staff being aware of what I actually do for a living."
Olivia was weighed and measured in her last term before leaving Trewirgie Junior School in Redruth, Cornwall, in December 2015.
The National Child Measurement Programme measures the height and weight of children when they start and leave all primary schools to assess obesity levels.
It was set up as part of a government strategy to tackle childhood obesity and Olivia's tests were carried out by Cornwall Council's Public Health team.
Lyndsay has not revealed Olivia's exact results, but said her daughter had a score which was just above the normal BMI range.
"Olivia is now 158cm tall and was one of the tallest children in her year," Lyndsay explained.
"After receiving the letter she was so distraught, I had to pull out my notes from university to convince her that she has no problem as she refused to eat anything for two days.
"They need to put something else in place, don't just bring a measuring tape and scales into school to stress children about it."
A spokesperson for the NCMP scheme said: "The results are sent home in a confidential letter to the parents and not to the child.
"It is a parent's decision to share the information; we are more than happy to provide advice and support about how to do this in the most supportive way, causing the least distress to the child.
"NCMP measurements are clinical measurements that a GP would use as an initial assessment of child body mass.
"The measurements should be used as part of a process to monitor child growth.
"By sending information to parents they have the opportunity to review and monitor and important aspect of their child's health.
"The personal letter providing the measurement is sent to parents directly in a confidential envelope enabling parents to choose how and if they would like to discuss the measurements with their child, we offer support to parents through this process.
"If measurements are not what parents would expect or if measurements are outside the healthy weight range, we recommend having a discussion with a GP or the Cornwall Healthy Weight team to find out more about the measurement and what it might mean for their child's long term health.
"We listen to feedback from parents and schools and use this to continually improve the way the programme is delivered.
"The NCMP is one way we can start to tackle unhealthy weight in our children.
"BMI centile for children takes height, weight, age and sex into account and is an accurate indicator of when a child is carrying excess weight, even in tall children."