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Primary Prevention – Maintains healthy weight

Maintains healthy weight

Evidence summary

There is strong evidence from a number of trials that there is favourable and consistent effect of aerobic physical activity on achieving weight maintenance with  less than 3% change (1). Similar data however notes there is no effect in achieving 5% weight loss (Physical activity alone)  – unless from large volumes or with iso-calorific diets (such weight loss may not be considered as primary prevention)(1).

The general consensus is of a moderate effect of physical activity on the risk of obesity with up to a 10% risk reduction. However, this is achieved primarily through weight maintenance from aerobic activity (2).

A longitudinal study on the association between sedentary behaviour and childhood obesity concluded that targeting sedentary behaviour may be effective for preventing obesity in the periods where children normally have large increases in sedentary time (ages 9-12)(4)

Note must be made however of studies showing that obese men who were moderately/highly fit had less than half the risk of dying than the normal-weight men who were unfit (3).

Although, regular physical activity helps with weight management, physical activity is linked with positive health outcomes whether or not individuals lose weight (3).

The aetiology of obesity in youth and adults is likely the result of a complex interplay of multi-causal influences (5). The evidence is not strong that physical activity alone is an adequate method of prevention, however in combination with other strategies taking into account the complex relationships and mechanisms of suspected behaviours affecting obesity, there is likely to be a large positive effect on obesity prevention (5).

A systematic review of the evidence regarding efficacy of obesity prevention interventions among adults proved that physical activity alone had worse outcomes than both diet alone and worse outcomes than physical activity and diet intervention combined, with the latter showing the most promising results (6).

Quality of evidence

Moderate to high quality

Strength of recommendation



  1. Start active, stay active: report on physical activity in the UK.

[online] Available at: GOV.UK. (2018).

  1. Exercise the Miracle Cure.

(2015). [ebook] Available at:…/2016/05/Exercise_the_Miracle_Cure_0215.pdf [Accessed 9 Jun. 2018].

  1. Physical inactivity: the biggest public health problem of the 21st century.

Br J Sports Med. 2009 Jan;43(1):1-2. Blair SN1.

  1. Longitudinal study of the associations between change in sedentary behavior and change in adiposity during childhood and adolescence: Gateshead Millennium Study. International Journal of Obesity, 41(7), pp.1042-1047. Mann, K., Howe, L., Basterfield, L., Parkinson, K., Pearce, M., Reilly, J., Adamson, A., Reilly, J. and Janssen, X. (2017).
  1. Prevention of overweight and obesity in children and adolescents : Critical appraisal of the evidence base

Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. Nov; 59(11):1423-1431 Pigeot I, Baranowski T, Lytle L, Ahrens W. (2016)

  1. A systematic review of the evidence regarding efficacy of obesity prevention interventions among adults.

Obesity Reviews, 9(5), pp.446-455. Lemmens, V., Oenema, A., Klepp, K., Henriksen, H. and Brug, J. (2008).