Commercial weight loss diets meet nutrient requirements in free living adults over 8 weeks: a randomised controlled weight loss trial.

OBJECTIVE: To investigate the effect of commercial weight loss programmes on macronutrient composition and micronutrient adequacy over a 2 month period. DESIGN: Adults were randomly allocated to follow the Slim Fast Plan, Weight Watchers Pure Points Programme, Dr Atkins' New Diet Revolution, or Rosemary Conley's "Eat Yourself Slim" Diet & Fitness Plan. SETTING: A multi-centre randomised controlled trial. SUBJECTS: 293 adults, mean age 40.3 years and a mean BMI 31.7 (range 27-38) were allocated to follow one of the four diets or control group. Subjects completed a 7-day food and activity diary at baseline (prior to randomisation) and after 2 months. Diet records were analysed for nutrient composition using WinDiets (research version). RESULTS: A significant shift in the macronutrient composition of the diet with concurrent alteration of the micronutrient profile was apparent with all diets. There was no evidence to suggest micronutrient deficiency in subjects on any of the dietary regimens. However, those sub-groups with higher needs for specific micronutrients, such as folate, iron or calcium may benefit from tailored dietary advice. CONCLUSION: The diets tested all resulted in considerable macronutrient change and resulted in an energy deficit indicating dietary compliance. Health professionals and those working in community and public health should be reassured of the nutritional adequacy of the diets tested. TRIAL REGISTRATION NUMBER: NCT00327821.

Randomised controlled trial of four commercial weight loss programmes in the UK: initial findings from the BBC "diet trials".

OBJECTIVE: To compare the effectiveness of four commercial weight loss diets available to adults in the United Kingdom. DESIGN: Six month multicentre randomised unblinded controlled trial. SETTING: Community based sample of otherwise healthy overweight and obese adults. INTERVENTIONS: Dr Atkins' new diet revolution, Slim-Fast plan, Weight Watchers pure points programme, and Rosemary Conley's eat yourself slim diet and fitness plan. MAIN OUTCOME MEASURES: Weight and body fat changes over six months. RESULTS: All diets resulted in significant loss of body fat and weight over six months. Groups did not differ significantly but loss of body fat and weight was greater in all groups compared with the control group. In an intention to treat analysis, average weight loss was 5.9 kg and average fat loss was 4.4 kg over six months. The Atkins diet resulted in significantly higher weight loss during the first four weeks, but by the end was no more or less effective than the other diets. CONCLUSIONS: Clinically useful weight loss and fat loss can be achieved in adults who are motivated to follow commercial diets for a substantial period. Given the limited resources for weight management in the NHS, healthcare practitioners should discuss with their patients programmes known to be effective. TRIAL REGISTRATION: Clinical trials NCT00327821.