A little bit of what you fancy does you good. Everything in moderation. A balanced diet is a healthy diet. Who hasn't heard these phrases repeated ad nauseam. The mantras most of us were raised on.

Not any more.

The Government's food police have instead devised a convoluted Nutrient Profiling Model (NPM) against which any food wishing to advertise to children will be scored. That might sound innocent enough but the trouble is it totally fails to take into account how people actually eat and as a result casts a veil of suspicion over products children and adults have enjoyed for generations without any harmful health implications.

The Food Standards Agency spent months and thousands of pounds huddled with food scientists, industry experts and various do-gooders only to come up with a model that almost no one thinks is perfect and many think is fundamentally flawed.

The model dictates that every food, from oven chips to Rice Krispies, is scored according to a basic 100g 'portion'. The FSA claims it chose 100g as a way of levelling the playing field for scoring all foods. However, this 100g measure also means foods we only ever eat in small portions such as cheese, dried raisins or Marmite are treated in exactly the same way as a double-deck burger from the local fast food joint.

We explain the intricacies of how the model works on p38, but, suffice to say, while it does indeed manage to catch out cereals such as Coco Pops and many high-fat takeaway dishes, it also firmly labels foods such as cheese, honey, raisins and Greek yoghurt as junk food- foods that most parents are proud to feed their kids.

Raisins don't escape the ban, even though the sugar they contain is natural fruit sugar - the Nutrient Profiling Model basically puts them in the same camp as confectionery. Honey suffers a similar fate. And Marmite, despite the fact that a typical portion would be 5g, also comes in for a coshing because the NPM insists it is scored based on a 100g portion and fails on its salt content.

In the meantime, many ready meals escape unscathed. Despite the fact that per portion they are often fat, sugar and salt heavy, using the same 100g measure, they fly under the model radar.

Cheese is perhaps one of the most contentious foods to be caught by the FSA's model. It is a natural, calcium-rich food that has formed part of a healthy diet for UK children for as long as anyone can remember. Yet the model now deems it too unhealthy to be advertised to children.

Obviously it scores highly for fat content, but because it doesn't contain fruit, veg or nuts it can't balance out its points with a protein score.

Gaynor Bussell, the Food and Drink Federation's nutrition manager, says it's as if every product scored under the model must be a complete food in its own right.

White bread, the scourge of the healthy eating brigade, also escapes censure. But most breakfast cereals are now firmly classed as 'junk' despite the fact that parents find getting children to eat any breakfast at all a challenge.

No one is debating the need for action against the growing obesity crisis, but devising a model that sits as judge and jury on individual foods, scored in isolation regardless of how they're usually eaten as part of a wider diet, is ludicrous.

The model also leaves little room for food brands to manoeuvre or innovate. For instance, products that are naturally higher in fat or sugar but eaten in small quantities, such as spreads, sauces, or mayonnaise, would still 'fail' even if reformulated as lower-fat or sugar variants. Hardly an inducement for the industry to seek healthier alternatives.

Despite a raft of sound evidence to damn the NPM, the FSA has ploughed on regardless. "The Nutrient Profiling Model is not scientifically based," says Bussell, "either in its fundamental purpose (for example, no evidence exists that nutrient profiling has been effective for any purpose) or in the way it was developed - the scores are assigned and worked out simply to fit pre-conceived ideas of what should be 'healthy' or 'unhealthy' food. Moreover the model takes no account of the amount eaten or the frequency of consumption."

She adds: "Because the model is based on 100g of product and not per portion, foods that are more concentrated in sugar or salt - such as ketchup - but eaten in small amounts are demonised. Also, the FSA model is based on a limited range of nutrients, plus energy. No account is taken of levels of important nutrients like calcium and vitamins and iron, and non-nutrients such as antioxidants."

Bussell believes the FSA manipulated the model to suit its purposes. "At the final stage and during the public consultation period, the model was revised with the effect of preventing foods with significant levels of protein from being classed as 'healthy' if they also had high levels of the politically sensitive nutrients. In nutrition terms this is quite illogical and runs counter to the concept of balancing intakes of macro and micro-nutrients in the diet."

Even the British Nutrition Foundation, one of the organisations involved in developing the FSA's model, raised concerns about such a product-specific way of looking at a diet. In its original submission to the FSA as part of the NPM consultation period, it stated: "Dietary variety is the bedrock of good nutrition; achieving this usually involves eating small amounts of a diverse range of food items, some of which are a rich source of essential nutrients but are also high in fat or total sugars on a 100g basis (eg dried fruit, nuts, cheese). It would be highly undesirable if this diversity were compromised."

It added: "In light of the steps we understand are already being taken by the industry with respect to children's advertising, we are not convinced that use of nutrient profiling, with the inherent problems it carries, will add anything."

Of course the food industry, particularly those who make and sell breakfast cereals and cheese, have lobbied hard for change, but it seems the FSA and Ofcom have largely ignored them.

The plight of the cheese industry is now being championed by Dan Rogerson, Liberal Democrat MP for North Cornwall and chairman of the all-party parliamentary group on cheese. At the end of January Rogerson tabled an Early Day Motion calling on the government to revise the Nutrient Profiling Model.

This week he voiced his support for The Grocer's campaign, saying: "Cheese is not a junk food, it is a natural product that has been eaten for hundreds of years."

The Early Day Motion has already secured the support of 30 MPs and continues to gather momentum. Rogerson is now planning to take the issue to health minister Caroline Flint hoping she might intervene.

Needless to say these are just a few of the many voices of reason totally disregarded by the FSA's obsessive pursuit of a handful of products.

But wait. It gets worse. The FSA has always billed the model as a tool purely for judging which foods can and cannot advertise to children, but The Grocer understands this could be just the thin edge of the wedge.

The European Commission has just published new regulations governing health and nutrition claims on food. It believes that nutrient profiling would prevent foods high in fat, sugar or salt making any health claims to all age groups simply because they were fortified with vitamins and minerals. So honey, cheese, Marmite et al would be further stigmatised.

The Commission wants some type of nutrient profiling to be in place by 2009. Many consider it highly likely the UK's model will be used as a starting point.

Innovation would be one of the first casualties because many brands simply wouldn't be allowed to flag up significantly reduced levels of salt, sugar, or fat if the product still 'failed' to score well .

If the industry gives in to Nutrient Profiling now this controversial and fundamentally flawed benchmarking system for food may become the blueprint by which government dictates all our diets. Surely we cannot allow that to happen. nOur Open letter

We call on you as head of broadcasting regulator Ofcom to reconsider the basis on which food and drink brands qualify to advertise during children's television programming.

This is not a campaign to stop the advertising ban on junk food. However, we believe the Nutrient Profiling Model developed by the FSA and used by Ofcom to determine its policies on advertising to children penalises many nutritious foods. Common sense dictates that dietary variety should be the foundation of good nutrition.

By judging the nutritional value of all foods based on a 100g portion, the NPM unfairly victimises many foods that legitimately form part of a healthy, balanced diet, especially those generally consumed in small quantities, infrequently or in combination with other foods.

We look forward to your earliest response.

The Grocer