Sandra and Pauline are room mates. They share the same fridge and eat a lot of junk food. Sandra is fat and Pauline is size 10 and never puts on weight.
Sandra, who's spent most of her life on and off diets, dreams about being as slim as Pauline and plans another diet. Pauline reads Grazia magazine and, while she knows she's not unhealthily fat, she also wants to lose weight and is a serial dieter. Both women promise each other they'll go on a diet on Monday, but like the other 98 people out of 100 who diet, it's not long before they're both back on a junk food binge.
Meanwhile, at the Houses of Parliament offices, Stephen, a friend of Sandra and Pauline and a uk.gov web page editor, is updating the statistics on the Department of Health web page titled Health risk and costs of obesity. Stephen types:
"Around 58% of type 2 diabetes, 21% of heart disease and between 8% and 42% of certain cancers are attributable to excess body fat."
Stephen feels good about educating the public on the dangers of obesity but he's worried about his fat friend Sandra, so he phones Pauline and they decide to warn her together about her risk of obesity-related disease.
When he goes round to visit Sandra and Pauline for beers and KFC at the weekend, he and Pauline gently persuade Sandra to lose weight. Sandra cries but sees that her friends care about her and says she'll try her best. Pauline isn't fat, so she doesn't consider her health at risk, but as she'd like to be a size smaller she promises Sandra she'll help her by dieting with her.
At this point, we zoom into a CSI-type reconstruction of inside Pauline's body as she persuades her friend to lose weight. The web of fatty tissue stored inside her is at a dangerously high level and it's been spilling into her bloodstream, damaging her organs.
Sandra's fat is stored under her skin and so while her continual eating of junk food means she's moving towards possible disease, the way she stores fat away from her organs, means the threat of illness is less immediate than it is for thin Pauline.
At this stage, however, both women are at risk of disease. Their diets, as usual, fail.
A year later and Sandra has moved out. She got in with a crowd of body image activists, adopting a healthy lifestyle. She finds the more she develops confidence in herself as she is, no longer waiting to lose weight before she lives her life, the less she's drawn to bingeing on junk food. She eats much more intuitively, and swims daily. She lost a bit of weight, but not much.
Every time her new lifestyle causes weight loss she starts getting obsessed with losing more, then she starts counting up how many calories she's had over the week and plans to eat the same again next week, calculating another 3lb loss - and pretty soon she finds herself back into dieting, which always ends up in a binge. Sandra works out that the less focus she puts on losing weight the healthier she behaves. So she's thrown out her bathroom scales. She's found dieting to be the biggest risk to her health and hardest thing to stop!
Pauline, however, continues trying to reach her size 8 goal, as seen in Grazia, even though, like the other 98% of people on the same track, she keeps on failing and her junk food bingeing is worse than ever. She recently fell ill and found she has type 2 diabetes.
Pauline's illness worried Sandra, so she went for a check up. Her doctor is perplexed: even though she's obese, all of her medical tests show she's perfectly healthy and at no risk at all of any of the diseases normally associated with being fat.
Now only one of these women is at risk of 'obesity related disease' and it's not the fat one.
So where is Pauline in the Department of Health Statistics? Is Pauline in the other 42% of type 2 diabetes, 79% of heart disease and between 58% and 92% of certain cancers NOT attributable to excess body fat? And why are the Sandras of the world, the fat and fit, lumped in with the fat and unfit?
Millions of Sandras and Paulines exist. They show that obesity related illnesses are not related to obesity at all but to lifestyle and more specifically to pressure to be thin and dieting! So why is our Government advising us that obesity causes disease and advising weight loss and dieting, the real causes of these diseases?
Next week: Who Funds Government Public Health Advice?
Hear me discussing dieting on BBC Radio 4 Woman's Hour on Tuesday 14 Feb at 10am
Follow Sue Thomason on Twitter: www.twitter.com/Antidieter