Commercial weight loss diets meet nutrient requirements in free living adults over 8 weeks: A randomised controlled weight loss trial
Nutrition Journal
Commercial weight loss diets meet nutrient requirements in free living adults over 8 weeks: A randomised controlled weight loss trial
Helen Truby 2
Rebecca Hiscutt 1
Anne M Herriot 1
Manana Stanley 1
Anne deLooy 0
Kenneth R Fox 6
Susan Baic 6
Paula J Robson 5
Ian Macdonald 4
Moira A Taylor 4
Robert Ware 3
Catherine Logan 5
MBE Livingstone 5
0 Faculty of Health Sciences, University of Plymouth , Plymouth, PL6 9BH , UK
1 Faculty of Health Sciences, University of Surrey , Guildford, GU2 7XH , UK
2 Children's Nutrition Research Centre, Royal Children's Hospital , Herston, Qld , Australia , 4029
3 School of Population Health, University of Queensland , Herston , Australia , 4029
4 School of Biomedical Sciences, University of Nottingham , Nottingham, NG7 2UH , UK
5 Northern Ireland Centre for Food and Health, University of Ulster , Coleraine, BT52 1SA , Northern Ireland
6 Department of Exercise and Health Sciences, University of Bristol , Bristol, BS8 1TP , UK
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
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Introduction
The slimming industry is a thriving and lucrative business
in many developed countries throughout the world. In the
UK, at any one time, it is estimated that almost two in five
women and one in six men are on some kind of reducing
diet. The continued rise in obesity supported by the
obesogenic environment, combined with a desired society
image of a 'slim body' being ideal [1] suggests that this
situation is likely to continue. There is a plethora of weight
loss regimens marketed at the lay public. The theories
underpinning these, and the marketing techniques used
to sell them range from little scientific basis to having a
reasonably robust scientific basis [2]. The popularity of a
given diet often bears little relation to the scientific
evidence base for its efficacy [3].
An excellent example of the impact and resulting
confusion that a diet can cause among both the lay public,
academics and health professionals is the internationally
popular low carbohydrate (CHO) Atkins diet [4]. The
potential detrimental health effects such a dramatic
alteration in macronutrient intake could provoke has caused
concern in many esteemed professional bodies [5]. The
current lack of credible evidence about its long term safety
has meant that health practitioners have been divided in
their response [6] with most dismissing it as a viable or
safe weight loss regimen. However, there is a growing
evidence base that suggests reduced CHO diets may not have
all the adverse effects on cardiovascular risk factors and
especially lipid profile previously postulated [7-9]. In
short term studies (up to 12 months), low CHO diets
seem to be at least as effective in achieving weight loss as
more widely endorsed methods of energy reduction, such
as low fat diets [8,7,10,11]. However, there is no
information in the literature to date that reports extensively on the
actual nutritional composition of a low CHO diet in
freeliving subjects.
The scale of the obesity problem and the limitations
within health systems to provide weight management
advice, mean that the vast majority of people trying to lose
weight are likely to do so on their own initiative and use
whatever sources of information they have to hand. Thus
evaluation of the effectiveness and impact of popular diets
is important and has not to date been rigorously
investigated. There is very little information on the effect that
commercial diets have on the food choices of people
undertaking these regimens in an unsupervised free-living
populat (...truncated)