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Should health policy focus on physical activity rather than obesity? Yes

BMJ 2010; 340 doi: (Published 25 May 2010) Cite this as: BMJ 2010;340:c2603
  1. Richard Weiler, specialist registrar in sport and exercise medicine, locum general practitioner1,
  2. Emmanuel Stamatakis, senior research associate2,
  3. Steven Blair, professor3
  1. 1Department of Trauma and Orthopaedics, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London W6 8RF
  2. 2Department of Epidemiology and Public Health, University College London, London
  3. 3Departments of Exercise Science and Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
  1. Correspondence to: R Weiler: richard.weiler{at}

    Richard Weiler and colleagues argue that losing weight is not essential to get benefit from physical activity, but Timothy Gill and colleagues (doi:10.1136/bmj.c2602) believe that tackling all the causes of obesity is essential to improve public health

    Physical inactivity is one of the greatest health threats facing developed nations today. In his latest annual report England’s chief medical officer acknowledged that the benefits of regular physical activity on health, longevity, and well being “easily surpass the effectiveness of any drugs or other medical treatment.”1

    When activity is measured objectively with accelerometers, 95% of the population in England2 and the United States3 did not meet the admittedly modest recommended amounts of weekly physical activity to confer important health benefits (30 minutes’ moderate to vigorous  physical activity on at least five days a week or equivalent4 5). This is alarming given that numerous authoritative sources, including a systematic review6 and consensus statements from the International Association for the Study of Obesity7 and the British Association for Sport and Exercise Sciences,8 have all concluded that meeting these targets is not enough to prevent obesity and that even more exercise is needed to stop weight regain in obese people who have lost large amounts of weight. Thus a focus on obesity rather than numerous other benefits of physical activity could misinform and discourage many people from exercise.

    Risks of physical inactivity

    Physical inactivity is an important cause of numerous diseases.9 Good quality evidence from large cohort studies confirms that physical inactivity rather than obesity is the causal factor for cardiovascular disease, coronary heart disease, type 2 diabetes, mental health illness, reduced quality of life, dyslipidaemias, hypertension, arrhythmias, increased inflammatory markers, myocardial infarction, dementia, stroke, cancer, fatigue, osteoporosis, fractures, falls, and ultimately death.4 5 10

    Increases in physical activity can both treat and prevent these unwanted conditions. A synthesis of systematic reviews and meta-analyses concluded that physically active people are at about half the risk of developing coronary heart disease compared with those with a sedentary lifestyle and that regular physical activity is associated with reduced risk of diabetes, obesity, osteoporosis, and colon cancer and improved mental health.11

    Fitness versus fatness

    A recent meta-analysis suggests that cardiorespiratory fitness, which is developed and maintained by regular physical activity, is a better predictor of mortality than obesity.9

    Evidence from Scotland analysing the medical records of 13 726 people (6102 men) shows that even when body mass index is taken into account, all types of physical activity are linked to reduced mortality.12 Data from 40 842 men and 12 943 women participating in the Aerobics Center Longitudinal Study showed that if everyone had a moderate level of cardiorespiratory fitness, overall mortality would be reduced by about 17%, whereas if no one was obese the mutually adjusted reduction would be only 2-3%.13 Sui and colleagues found that cardiorespiratory fitness was far more important than high body mass index, percentage body fat, or high waist circumference as a determinant of mortality in a cohort of 2603 people aged 60 or older.14 This report is important because it is one of the few in which fitness was measured objectively by a maximal exercise test and fatness was assessed by laboratory measurements of percentage body fat and waist circumference.

    Obesity treatment

    Because physical activity is associated with improved risk factors for disease even if no weight is lost, a focus on weight loss is largely misleading.10 In addition, drugs and bariatric surgery, which are becoming common options to deal with obesity,15 have serious risks.16 17 The broader long term benefits of these treatments are currently limited or non-existent,18 and they certainly do not have the multiple collateral health benefits of physical activity.19

    Health policy strategy

    The 2007 Foresight report suggested that since the 1980s in the UK we have become less active because of our environment.20 Review evidence suggests characteristics of the built environment strongly influence physical activity.21 Fortunately, there are many opportunities to change built environments. Community patterns of land use and transportation infrastructure that support walking and cycling to nearby destinations are strongly related to physical activity.22 Environmental interventions to increase access to physical activity suggest that creating or improving access to places for physical activity can result in a 25% increase in the number of people who are active at least three times a week.23


    Obesity is one of many symptoms of poor lifestyle associated with morbidity and mortality. These undesirable health risks can be greatly reduced by physical activity leading to improved fitness, even in the absence of weight loss.

    The public welfare burden of physical activity in England is immense, with the annual estimated cost of physical inactivity £8.2bn (€9.5bn; $12bn) in 2002, whereas treatment of obesity related comorbidities is estimated at £4.2bn.1 Physical inactivity is the only risk factor for chronic disease that has an adult population prevalence of 95%.2 3 If health policy, modern medicine, and healthcare professionals focus on fighting physical inactivity we will no longer need to concentrate on the negative societal stigma of obesity.


    Cite this as: BMJ 2010;340:c2603


    • Competing interests: All authors have completed the unified competing interest form at (available on request from the corresponding author) and declare (1) no support for the submitted work; (2) SB serves on the scientific or medical advisory boards of Alere, Jenny Craig, and Technogym and has received consultation fees for these services. He also has received research funding from the US National Institutes of Health, Body Media, Coca Cola, and the US Department of Defense. (3) their spouses, partners, or children have no financial relationships that may be relevant to the submitted work; and (4) no non-financial interests that may be relevant to the submitted work.

    • Provenance and peer review: Not commissioned; not externally peer reviewed.