Evidence summary (Updated 2022)
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) .
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 .
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 .
Although, regular physical activity helps with weight management, physical activity is linked with positive health outcomes whether or not individuals lose weight .
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 .
Recent research has shown a positive association between physical activity and weight maintenance from multiple studies . This appears to be more reliably demonstrated in those performing moderate to vigorous physical activity for a minimum of 150 minutes per week. Primary care-based initiatives targeting those with chronic diseases also fared well; reducing individuals BMI and an increase in METS . A systematic review looking at population wide initiatives suggested they have been associated with a reduction in individuals BMI, although these benefits are fairly modest .
There is a paucity in the literature as to whether light intensity exercise may provide a reduction in the risk of developing obesity .
Several small studies compared BMI changes following physical activity in ethnic minorities and found no reduction . However gestational weight gain control was effective in 21 RCT’s, particularly when combined with dietary advice/modification . The trend in the literature is for physical activity to be measured in combination with other modalities or against numerous parameters which has left a degree of confounding variables and/or bias, particularly in adults .
There is still moderate quality evidence that physical activity initiatives, prescription or programs are beneficial in weight maintenance and reduction in risk of obesity in adults and children [8,15]
Quality of Evidence
Grade B – Moderate to high quality
Strength of recommendation
Grade 1 – strong
Physical activity is shown to help with weight maintenance and should be encouraged along with dietary and lifestyle modifications to prevent obesity.
 Start active, stay active: report on physical activity in the UK. [online] Available at: https://www.gov.uk/government/publications/start-active-stay-active-a-report-on-physical-activity-from-the-four-home-countries-chief-medical-officers GOV.UK. (2018).
 Exercise the Miracle Cure. (2015). [ebook] Available at: https://www.aomrc.org.uk/…/2016/05/Exercise_the_Miracle_Cure_0215.pdf [Accessed 9 Jun. 2018].
 Blair SN1 (2009) Physical inactivity: the biggest public health problem of the 21st century. Br J Sports Med. 2009 Jan;43(1):1-2.
 . Mann, K., Howe, L., Basterfield, L., Parkinson, K., Pearce, M., Reilly, J., Adamson, A., Reilly, J. and Janssen, X. (2017). 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
 Pigeot I, Baranowski T, Lytle L, Ahrens W. (2016). Prevention of overweight and obesity in children and adolescents: Critical appraisal of the evidence base. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. Nov; 59(11):1423-1431
 . Lemmens, V., Oenema, A., Klepp, K., Henriksen, H. and Brug, J. (2008). A systematic review of the evidence regarding efficacy of obesity prevention interventions among adults. Obesity Reviews, 9(5), pp.446-455
 Jakicic JM, Powell KE, Campbell WW, et al. (2018)PHYSICAL ACTIVITY GUIDELINES ADVISORY COMMITTEE*. Physical Activity and the Prevention of Weight Gain in Adults: A Systematic Review. Med Sci Sports Exerc. 2019 Jun;51(6):1262-1269.
 Goryakin Y, Suhlrie L, Cecchini M. (2018) Impact of primary care-initiated interventions promoting physical activity on body mass index: systematic review and meta-analysis. Obes Rev. Apr;19(4):518-528.
 Roberts S, Pilard L, Chen J et al. (2019) Efficacy of population-wide diabetes and obesity prevention programs: An overview of systematic reviews on proximal, intermediate, and distal outcomes and a meta-analysis of impact on BMI. Obes Rev. Jul;20(7):947-963
 Seral-Cortes M, De Miguel-Etayo P, et al. (2021) Effectiveness and process evaluation in obesity and type 2 diabetes prevention programs in children: a systematic review and meta-analysis. BMC Public Health. Feb 12;21(1):348
 Yuksel HS, Şahin FN, Maksimovic N, et al. (2020) School-Based Intervention Programs for Preventing Obesity and Promoting Physical Activity and Fitness: A Systematic Review. Int J Environ Res Public Health. Jan 3;17(1):347.
 Navidad L, Padial-Ruz R, González MC. (2021) Nutrition, Physical Activity, and New Technology Programs on Obesity Prevention in Primary Education: A Systematic Review. Int J Environ Res Public Health. Sep 28;18(19):10187.
 Bleich SN, Vercammen KA, Zatz LY, et al. (2018) Interventions to prevent global childhood overweight and obesity: a systematic review. Lancet Diabetes Endocrinol. Apr;6(4):332-346.
 Hayba N, Elkheir S, Hu J et al. (2020) Effectiveness of Lifestyle Interventions for Prevention of Harmful Weight Gain among Adolescents from Ethnic Minorities: A Systematic Review. Int J Environ Res Public Health. Aug 20;17(17):6059.
 Shieh C, Cullen DL, Pike C et al. (2018) Intervention strategies for preventing excessive gestational weight gain: systematic review and meta-analysis. Obes Rev. Aug;19(8).
 Tseng E, Zhang A, Shogbesan O, et al. (2018) Effectiveness of Policies and Programs to Combat Adult Obesity: a Systematic Review. J Gen Intern Med. Nov;33(11):1990-2001