The rules in this section are designed to ensure that marketing communications for slimming and weight control products receive the necessary high level of scrutiny.

See CAP Slimming Guidelines for Press Advertisements.


This section applies to marketing communications for weight control and slimming foodstuffs, aids (including exercise products that make weight-loss or slimming claims), clinics and other establishments, diets, medicines, treatments and the like. If applicable, they must comply with Section 12: Medicines, Medical Devices, Health-related Products and Beauty Products and Section 15: Food, Food Supplements and Associated Health or Nutrition Claims).



A weight-reduction regime in which the intake of energy is lower than its output is the most common self-treatment for achieving weight reduction. Any claim made for the effectiveness or action of a weight-reduction method or product must be backed, if applicable, by rigorous trials on people; testimonials that are not supported by trials do not constitute substantiation.


Obesity in adults is defined by a Body Mass Index (BMI) of more than 30 kg/m2. Obesity is frequently associated with a medical condition and, except where stated in 13.2.1, a treatment for it must not be advertised to the public unless it is to be used under suitably qualified supervision. Non-prescription medicines that are indicated for the treatment of obesity and that require the involvement of a pharmacist in the sale or supply of the medicine may nevertheless be advertised to the public.


Lifestyle weight management programmes which meet the following standards may make responsible references to obesity in their marketing communications. These programmes must:

  • be shown to be effective at 12 months or beyond
  • last at least three months
  • be multi-component; addressing dietary intake, physical activity levels and behaviour change
  • be developed by a multi-disciplinary team; including input from a registered dietician, registered practitioner psychologist and a qualified physical activity instructor, and
  • be provided by staff who are trained to deliver the programme in question.

Marketers should have regard to the guidance on "Managing overweight and obesity in adults – lifestyle weight management services" published by the National Institute for Health and Care Excellence (NICE).


Marketing communications for any weight-reduction regime or establishment must neither be directed at nor contain anything that is likely to appeal particularly to people who are under 18 or those for whom weight reduction would produce a potentially harmful body weight (BMI of less than 18.5 kg/m2). Those marketing communications must not suggest that being underweight is desirable or acceptable.


Before they make claims for a weight-reduction aid or regimen, marketers must show that weight-reduction is achieved by loss of body fat. Combining a diet with an unproven weight-reduction method does not justify making weight-reduction claims for that method.


Marketers must be able to show that their diet plans are nutritionally well-balanced (except for producing a deficit of energy) and that must be assessed in relation to the category of person who would use them.


Vitamins and minerals do not contribute to weight reduction but may be offered to slimmers as a safeguard against any shortfall in recommended intake when dieting.


Marketers promoting Very Low Calorie Diets or other diets that fall below 800 kilo-calories a day must do so only for short-term use and must encourage users to take medical advice before embarking on them. Marketers should have regard to the guidance on "Obesity: the prevention, identification, assessment and management of overweight and obesity in adults and children" (2006) published by the National Institute for Health and Care Excellence.


Marketing communications for diet aids must make clear how they work. Prominence must be given to the role of the diet and marketing communications must not give the impression that dieters cannot fail or can eat as much as they like and still lose weight.


Marketing communications must not contain claims that people can lose precise amounts of weight within a stated period or, except for marketing communications for surgical clinics, establishments and the like that comply with rule 12.3, that weight or fat can be lost from specific parts of the body.


Marketing communications for surgical clinics, establishments and the like that comply with rule 12.3 must not refer to the amount of weight that can be lost.


Claims that an individual has lost an exact amount of weight must be compatible with good medical and nutritional practice. Those claims must state the period involved and must not be based on unrepresentative experiences. For those who are normally overweight, a rate of weight loss greater than 2 lbs (just under 1 kg) a week is unlikely to be compatible with good medical and nutritional practice. For those who are obese, a rate of weight loss greater than 2 lbs a week in the early stages of dieting could be compatible with good medical and nutritional practice.


Health claims in marketing communications for food products that refer to a rate or amount of weight loss are not permitted.


Resistance and aerobic exercise can improve muscular condition and tone and that can improve body shape and posture. Marketers must be able to substantiate any claim that such methods used alone or in conjunction with a diet plan can lead to weight or inch reduction. Marketing communications for intensive exercise programmes should encourage users to check with a doctor before starting.


Short-term loss of girth may be achieved by wearing a tight-fitting garment. That loss must not be portrayed as permanent or confused with weight or fat reduction.

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