Previous rules were designed to ensure adverts did not discourage essential treatment for certain serious medical conditions including obesity by promising over-the-counter solutions.

However CAP said the prevalence of obesity was now so serious and its effect on public health so well documented that changes to the code were needed.

The changes also came in light of a 2014 report from the UK’s National Institute for Health and Care Excellence (NICE) – the executive non-departmental public body of the country's department of health.

In the report it envisaged certain lifestyle weight management programmes would play a substantial role within a broader strategic approach to managing obesity, and suggested medical supervision was not always required in this.

CAP created a criteria for programmes eligible to reference obesity and target the obese.

According to the UK’s National Health Service (NHS), obesity effects one in every four adults and around one in every five children aged ten to 11 in the UK. Meanwhile the World Health Organisation (WHO) calculates that worldwide obesity has more than doubled since 1980. In 2014, over 1.9 billion adults were overweight of which 600 million were obese. An adult with a Body Mass Index (BMI) over 30 kg/m2 is generally considered obese. A person with a BMI equal to or more than 25 is considered overweight. BMI is calculated by dividing a person’s weight in kilograms by the square of the height in metres.

They must:

be shown to be effective at 12 months or beyond

last at least three months

be multi-facetted, addressing diet, physical activity and behaviour

be developed by a multi-disciplinary team to include input from a registered dietitian, registered practitioner psychologist and a qualified physical activity instructor

be provided by staff who are trained to deliver the programme in question

Further guidance online advises advertisers not to exaggerate expected rates of weight loss and to avoid causing offence.

CAP director Shahriar Coupal said in a statement: “These new rules strike a sensible balance; providing weight loss management programmes that meet necessary criteria the freedom to target their advertising at people who are obese while ensuring the right level of protections for consumers are in place.”​

The new rules will come into immediate effect but since the changes are significant CAP will conduct a review in 12 months.

Disbanding disproportionate prohibition ​

CAP said “some” ​of these programmes had been recognised as safe and effective ways for people to lose weight, and therefore it would be “disproportionate”​ to continue prohibiting the advertisement of these services to people who are obese.

“This rule change provides those who want help in losing weight, and who might benefit from a lifestyle weight loss programme, with more information, choice and support,”​ it said.

The changes came after a period of public consultation, in which CAP received feedback from the likes of the British Psychological Society (BPS), Saatchi & Saatchi, Slimming World and Weight Watchers UK.

Saatchi & Saatchi noted that while such weight loss programmes were restricted under the previous rules, surgical interventions were allowed to advertise more freely, which risked giving the impression that obesity always needed to be treated medically.

However, others expressed concern over the changes.

Dietitians in Obesity Management UK (DomUK) said it was not aware of any evidence that obese individuals were deterred from using weight management services because of advertising restrictions.

“If indeed there is no evidence, there is no need for the rules to be changed,”​ it wrote.

It said it was also concerned that those with a BMI over 30 were likely to have one or more comorbidities, which needed to be identified and monitored by healthcare professionals.

"The greater the degree of obesity, the more likely this is. While good quality weight management interventions should already be including this, we would welcome a recommendation to this effect as part of any change to the guidance.”​

CAP’s Advertising Guidance on health, beauty and slimming marketing communications that refer to medical conditions​​ as well as its AdviceOnline​​ has now been updated.

CAP is responsible for writing and updating the UK’s advertising codes, which are then administered by the UK’s Advertising Standards Authority (ASA).

January marked a milestone in the debate around how low-calorie and slimming foods should be regulated on an EU level when the European Food Safety Authority (EFSA) released an opinion​​ on what exactly a low-calorie diet replacement regime should contain.

Along with micronutrient specifications, it said foods intended to completely replace the diet of overweight and obese people should contain 600 calories, 75 g protein and 30 g carbs per day.