Last week, the papers were once again awash with the now familiar headlines about our nation’s spiralling “obesity crisis” and, in particular, emphasising the “fact” that a third of children leave primary school “dangerously overweight”.

The National Obesity Forum and other campaign groups reinforced the importance of weighing and measuring children in school and informing their parents if they are overweight. This, despite being a technique employed for years with no measurable positive impact, is still being peddled as an effective solution to childhood obesity levels.

If you read Megan Jayne Crabbe’s excellent book Body Positive Power, in which the author forensically dissects and examines studies on obesity and impact on health, as well as the role that the diet industry has to play, you’ll understand the flaws in such thinking. Saying that obesity causes heart disease, argues Crabbe, is like saying yellow teeth cause lung cancer without acknowledging that there is a missing link - smoking - which, in fact, causes both of those things. It’s a line of argument which makes the most basic error - mistaking correlation for causation.

Yes, sitting on your bum all day consuming vast quantities of processed food is bad for your health. It might also cause you to become fat. But saying that it is fat in itself that causes disease is not only misleading, it promotes the idea that losing weight by whatever means possible is always the “healthy” option.

Two years ago, I was commissioned to undertake a week-long experiment to be written up in a newspaper about the health impact of diets. It still has not been seen by the public, because the experiment found that weight loss does not automatically equal improved health and the newspaper and several of their “sister” publications could not find a good time to publish and not annoy their advertisers in the diet industry. This alone tells you everything you need to know about the way our health and bodies have been commoditised.

I have a BMI of 26.5. For those curious, I am just shy of six feet tall and a size 16. According to my doctor, my level of physical activity puts me in the “very active” bracket and my diet is “excellent”. Yet still, every time I go for a check-up, I’m told that my BMI is “slightly overweight” and that if I could “just lose about a stone” I’d be “healthier”. After years of having any ailment which happened to befall me, from eczema to a spontaneously ruptured spleen (which happens to hardly anyone whether they are fat or thin) blamed on my weight, I was thoroughly cheesed off.

Unhealthy diets

During a routine scroll through social media, I encountered a pop-up for a diet “guaranteeing” one stone of weight loss in a week. It looked gruesome (no oil, fats, dairy or carbs) but do-able compared with, say, the cabbage-soup diet, which experience told me I’d give up after a day. I am smart enough to know that if your goal is long-term weight loss, diets don’t work. Yet if what my doctor was telling me was true, my health should be better at the end of the week than it was at the beginning.

I, therefore, enlisted the help of a private Harley Street clinic, which comprehensively measured my physical health at the start and finish of the diet. Before commencing, I had healthily low blood pressure and cholesterol, good muscle definition, my heart was in great shape and I was well hydrated. By the end of the week not only had my cholesterol and body fat percentage both gone up (bodies burn muscle before fat when seeking sustenance) but the doctor advised me that my ketones, which indicate blood sugar, were at a dangerous level and actually went to a nearby coffee shop and bought me a cake after the consultation because he was worried I would faint.

Point proved, I think.

Children should exist in an environment where it’s easy for them to have healthy habits. That’s why I cautiously support mooted new laws which would ban fried chicken shops within a 400-metre radius of schools. That’s why ensuring a basic level of nutritional value in the food served by school canteens is important. That’s why we should fight the gradual erasing of time and resources for physical activity within the curriculum and local authorities closing down sports clubs and selling off school playing fields.

But focusing on the weight of individual children does precisely nothing other than to add guilt, shame and potential mental health issues into the mix. Furthermore, the tactic of simply alerting parents won’t do anything to help families who, for a variety of complex reasons, struggle to access healthy food and regular physical activity.

What it will do, however, is harm children like me - who are tall, muscular, broad and non-white (black and mixed-race children regularly have an “overweight” BMI despite being obviously slender). It took me twenty years of distressing feelings around food and my body, seven years of a full-blown eating disorder, a lengthy recovery process and re-learning how to eat intuitively and not to feel too embarrassed to exercise for me to regain what I had to begin with - a healthy body and a healthy mind.

I’d hate for the same fate to befall a current generation of young people.

Natasha Devon MBE is the former government mental health champion. She is a writer and campaigner and visits an average of three schools per week all over the UK. She tweets @_natashadevon. Find out more about her work here