Impact of physical activity and diet on health - Health Contents

1  Introduction

1. The impact of diet and physical activity on health is complex and multi-faceted. The committee reviewed recent progress in this area in order to make some recommendations for the next Government. In the time remaining in this Parliament we have tried to focus on a 'what works' approach based on existing evidence. We are very grateful to the many organisations and individuals who provided written and oral evidence to this inquiry. All the evidence we received is published in full on our website.[1] We would also like to thank our specialist adviser for this inquiry, Professor Mike Kelly.

2. NHS England's Five Year Forward View sets out the urgent need for "a radical upgrade in prevention and public health." It states, for example, that "it makes little sense that the NHS is now spending more on bariatric surgery for obesity than on a national roll-out of intensive lifestyle intervention programmes that were first shown to cut obesity and prevent diabetes over a decade ago."[2]

3. This introductory chapter gives a brief overview of the current situation and what is known about the impact of diet and physical activity on health. The second chapter discusses general principles and key responsibilities for tackling physical activity and diet. Our report centres around two key messages:

—  Physical activity—needs to be seen as a crucial health priority in its own right

—  Diet and obesity—it is time for a national debate about how to make it easier for people to make healthier diet and lifestyle choices.

The impact of physical activity on health

4. Physical activity is described as body movement that expends energy and raises the heart rate. Inactivity is classed as less than 30 minutes of physical activity a week, and sedentary time means time spent in low-energy postures, e.g. sitting or lying.[3] Globally, physical inactivity is the fourth leading risk factor for mortality (accounting for 6% of deaths). This follows high blood pressure (13%), tobacco use (9%) and high blood glucose (6%). Overweight and obesity are responsible for 5% of global mortality.[4] In the UK, physical inactivity directly contributes to one in six deaths.[5] Evidence suggests that sedentary

behaviour is independently bad for health.[6] The Chief Medical Officer has published guidelines on physical activity for different age groups and recommendations about limiting sitting time have been added to these.[7]

5. Public Health England state that the percentage of adults achieving recommended levels of physical activity has increased in the last fifteen years from 32% to 43% among men, and from 21% to 32% among women. In 2012, 21% of boys and 16% of girls aged 5-15 years met the national physical activity target.[8] The Active People Survey shows that 29% of people are currently classed as "inactive"—i.e. they fail to complete 30 minutes of moderate physical activity each week.[9]

6. Professor Nick Wareham of the MRC Epidemiology Unit and the Centre for Diet and Activity Research at the University of Cambridge, echoing the report of the CMO in 2013, cautions that these self-reported statistics on physical activity may be an overestimate, noting that "adults and children tend to overestimate how physically active they are, and we lack good nationwide data about actual levels of physical activity":

    Repeated cross-sectional surveys such as the National Diet and Nutrition Survey and Health survey for England provide information about behaviours. However, because this data is self-reported, its quality and reliability can be poor…objective accelerometer data suggest that only 6% of men and 4% of women achieve recommended level Both adults and children overestimate how physically active they are, and parents overestimate how active their children are.[10]

7. While measurement differences limit direct comparisons Everybody Active Every Day provides data showing that the problem is worse in the UK than many other countries.[11]

8. Public Health England provides the following statistics on physical activity:

·  Walking trips decreased by 30% between 1995 and 2013

·  64% of trips are made by car, 22% are made on foot, and 2% are made by bike

·  39% of non-disabled adults regularly take part in sport, compared to 18% of disabled adults.[12]

9. As well as describing the negative effects of inactivity on health, much of the written evidence we have received details the positive impacts of physical activity in unequivocal terms:

    We know that regular physical activity helps prevent and manage over 20 chronic conditions including coronary heart disease, stroke, type 2 diabetes, cancer, obesity, mental health problems and musculoskeletal conditions. In addition, evidence shows that there is a link between physical activity and good mental wellbeing. For example, exercise is moderately more effective than therapy for reducing symptoms of depression. It may also help people with generalised anxiety disorder, panic attacks and stress disorders.[13]

10. The Ramblers note that "unsurprisingly, physical activity has been described as a 'wonder drug'".[14] The University of Bedfordshire state that "we know of no single intervention with greater promise than physical exercise to reduce the risk of virtually all chronic diseases simultaneously"[15], and the Transport and Health Study Group put the positive argument for physical activity in even stronger terms:

    If physical activity were a drug then the range of its benefits on mental well being, mental illness, heart disease, obesity, diabetes and osteoporosis is such that no politician would dare withhold those benefits from the public. At a time when the NHS struggles to cope with the pressures of mental illness, obesity and diabetes, it is financially irresponsible to fail to promote physical activity.[16]

The impact of diet on health

Obesity and overweight

11. Overweight and obesity are commonly defined by Body Mass Index (BMI) in adults with overweight being defined as a BMI between 25 and 29.9 and obesity as a BMI of 30 or over.[17] For children, these BMI standards require adjustments for age and gender. Public Health England explain the importance of diet to weight:

    Excess weight gain results from an imbalance between energy consumed and energy expended and PHE recognises that eating less is crucial for weight loss. PHE estimates that the average man and woman in England consume respectively approximately 300 and 200 calories a day more than they need. Alcohol consumption is also linked to excess calorie intake and an emerging evidence base suggests that it and obesity compound problems such as fatty liver disease.[18]

12. Public Health England describe the negative health impacts of obesity:

    Being obese can increase the risk of developing a range of serious diseases, including hypertension, type 2 diabetes, cardiovascular diseases, several cancers, asthma, obstructive sleep apnoea, and musculoskeletal problems.[19]

13. They also note that obese children are more likely to be ill, absent from school, and suffer psychological problems such as low self-esteem and depression than normal weight children.

14. Public Health England provide the following statistics on the prevalence of obesity:

    Obesity levels remain high with two-thirds of the adult population, one in five 4-5 year olds and one in three 10-11 year olds in England [being] either overweight or obese. In the last decade, the prevalence of adult obesity has risen from 15% to 25%, whilst the prevalence of overweight has remained broadly stable (37%-39%) during this period. In the last seven years, the proportion of children aged 4-5 years who were obese has remained broadly stable (9.9%-9.5%) whilst the proportion of children aged 10-11 years who are obese has increased (17.5%-19.1%).

    Obesity and related conditions vary according to ethnic group, socioeconomic status and geography. Obesity disproportionately affects those in the most deprived social groups and evidence suggests that the inequalities gap in child obesity is widening.[20]

15. The Department of Health states that "the rising levels of overweight and obesity we have seen over the past 20 years or so appear to be stabilising, but at a very high level."[21] There is also recent evidence showing that the rates of morbid obesity in children are increasing.[22]

Trend in obesity prevalence among adults

Adult (aged 16+) obesity: BMI = 30kg/m2

Source - Health Survey for England 1993-2013 (3-year average)-Public Health England

Trend in excess weight among adults

Adult (aged 16+) overweight including obese: BMI = 25kg/m2

[Source - Health Survey for England 1993-2013 (3-year average)-Public Health England]


16. The impact of diet on health is not limited to its impact on weight. The Scientific Advisory Committee on Nutrition (SACN) recommendations for intakes of energy, nutrients, and some food groups are translated into nutrient and food based guidance for populations. This underpins dietary advice as depicted in the national food guide 'the eatwell plate' and the five-a-day advice for fruit and vegetables.[23]

17. Commenting on current eating habits, Public Health England state:

    The population overall is consuming too much saturated fat, non-milk extrinsic sugars (which includes added sugars and free sugars in fruit juices) and salt and not enough fibre, oily fish or fruit and vegetables. On average, no population age group meets current dietary recommendations. The diets of young children under four years are close to meeting recommendations while the diets of adolescents (particularly girls) are the worst. Some aspects of diet vary with income, for example fruit and vegetables, fibre and some micronutrients show a clear pattern of lower intakes in lower income groups. Over the last 10 years salt intakes of adults have reduced by 15% but remain above the maximum recommended level.

    Current intakes of sugar for all population groups exceed recommendations. Sugar increases the risk of tooth decay and of consuming too many calories, which, if sustained, causes weight gain and obesity.[24]

18. Consumption of food and drinks high in sugar increases the risk of the development of type 2 diabetes.[25]

19. The UK Faculty of Public Health argues that "for cardiovascular disease prevention, there is clear evidence that the Mediterranean diet, even just a handful of nuts and or liberal consumption of olive oil, is effective, and could lead to a rapid 30% reduction in deaths & non-fatal events. Furthermore, this demonstrates that a healthy diet is more powerful than statins."[26] In relation to children's eating habits, the Local Government Association notes:

    While the number of children eating the recommended amounts of fruit and vegetables has increased in recent years, 80 per cent of children still do not eat the recommended '5-a-day'. England's young people have the highest consumption of sugary soft drinks in Europe.[27]

Physical activity—a priority in its own right

20. One of the clearest messages the Committee has heard during the course of this inquiry is that the considerable health benefits of physical activity independent of weight must be more clearly acknowledged and communicated. The Royal College of Physicians told us:

    Often the benefits of physical activity are closely linked to reductions in obesity. The RCP however, strongly recommends that wider benefits of physical activity should be recognised and promoted. Individuals who are obese but have a good level of cardiorespiratory fitness (CRF) can have better health and wellbeing than an individual with an ideal body Mass Index (BMI) but low CRF. The wider health benefits of physical fitness should be promoted to improve the health of the nation.[28]

21. The written evidence received by the Committee also suggests that while physical activity has benefits for all people regardless of weight, and may help maintain weight loss, "increasing physical activity…is unlikely to be the best single strategy for combatting excess weight"[29]. The Department of Health agree, stating that "although physical activity brings important health benefits…for those who are overweight and obese, eating and drinking less is key to weight loss".[30]

22. Research very recently published by the MRC drawing on the EPIC (European Prospective Investigation into Cancer) study reported that in terms of reducing mortality risk, for the most inactive people, walking for around 20 minutes extra per day would have a greater positive impact than not being obese,[31] as Professor Nick Wareham explained:

    About 23% of people in that study—and there was a large group of people in that study from the United Kingdom—were in the category of being totally inactive; they had a sedentary job and did no recreational physical activity at all. That group had the highest mortality risk. If you look at the difference between that group and the moderately inactive, there was about a 20% reduction in mortality risk. Switching from being totally inactive to moderately inactive would require the equivalent of walking 20 minutes extra per day, which is a totally feasible public health transition. We estimated that, if everybody who was in that totally inactive category could move up to the next category, the impact on mortality would be of the order of 7%. That was greater than the impact of the avoidance of obesity. The important thing for the Committee is that that impact of physical activity was independent of obesity. So within the strata of whether someone is obese, overweight or a normal weight, the effect of physical activity was the same.[32]

23. Dr William Bird, a GP with an interest in physical activity and founder of Intelligent Health, reinforced this point:

    We have finally got the evidence to disentangle the connection between obesity and physical activity. I am grateful for obesity getting physical activity on the agenda because that has been the way it has managed to get up on to the podium, but we must not use weight loss as a measure of success for physical activity. Physical activity has always been the handmaiden of obesity—the way you have diet and physical activity for the objective of losing weight. That is no longer evidence based and should not be used again. Of course obesity is important, but physical activity in its own right has benefits. In fact only 10% of the benefits of physical activity for cardiovascular disease are weight-related. The other 90% are the anti-inflammatory effects—the other aspects of cellular change that take place when you are physically active.[33]

He went on to give the startling example that

    Giving a coronary stent to patients with stable angina or getting them to exercise for 20 minutes a day have exactly the same outcomes after one year, except that exercise is more effective.[34]

24. Professor Dame Sue Bailey, Chair of the Academy of Medical Royal Colleges, gave two further compelling examples of the impact of exercise on health—firstly that exercise can be beneficial for treating childhood depression, and should be used tried as a first line treatment, together with psychological therapies, before using drug treatments; and secondly that exercise is effective in strengthening bone density to prevent fractures in older people. In all of these examples exercise would be a far cheaper option. Professor Dame Sue Bailey went on to say that in her view it was "regrettable" that the evidence has been there for some time and "neither the public, politicians nor practitioners have gone with this sufficiently."[35] The Academy of Medical Royal Colleges has recently published a report entitled Exercise: the miracle cure and the role of the doctor in promoting it, aimed at publicising the "simple" message that "exercise is a miracle cure too often overlooked by doctors and the people they care for":

    The big four "proximate" causes of preventable ill-health are: smoking, poor nutrition…physical inactivity and alcohol excess. Of these, the importance of regular exercise is the least well-known. Relatively low levels of increased activity can make a huge difference. All the evidence suggests small amounts of regular exercise (five times a week for 30 minutes each time for adults) brings dramatic benefits. The exercise should be moderate—enough to get a person slightly out of breath and/or sweaty, and with an increased heart rate.

    Doctors are increasingly being asked to carry out a range of interventions when they see patients, including screening and changing behaviour, with initiatives such as 'Make Every Contact Count'. However this report calls on doctors to promote the benefits of regular physical activity to their patients and to communities in their wider roles as 'advocates for health'. We have some tips, but the message is simple. Exercise is a miracle cure too often overlooked by doctors and the people they care for.[36]

25. For too long, physical activity has been seen merely in the light of its benefits in tackling obesity. However, there is compelling evidence that physical activity in its own right has huge health benefits totally independent of a person's weight—in fact research recently published suggested that increasing physical activity levels could have greater impact on reducing mortality than reducing weight. The Chief Medical Officer's guidelines recommend levels of activity which will help people derive the greatest health benefits; but even small increases in activity levels can have a dramatic positive impact on health.

26. Diet, obesity, and physical activity all have important impacts on health. However, it is vital that the importance of physical activity for all the population—regardless of their weight, age, gender, health, or other factors—is clearly articulated and understood. We recommend that the Government, Public Health England and health professionals, in particular GPs, to take urgent action to communicate this crucial message to the public.

1   Health Select Committee, The Impact of physical activity and diet on health Back

2   NHS England Five Year Forward View (October 2014), p 9, p 11 Back

3   Public Health England, Everybody Active Every Day - an evidence based approach to physical activity (October 2014), p4 Back

4   Department of Health, Start Active Stay Active (July 2011), p10 Back

5   Public Health England, Everybody Active Every Day - an evidence based approach to physical activity (October 2014),p6 Back

6   Biddle, S., Pearson, N., Ross, G.M. Braithwait, R. (2010) Tracking of sedentary behaviours of young people: a systematic review, Preventive Medicine; 51: 345-51. Rezende et al. BMC Public Health 2014, 14:333 Sedentary behavior and health outcomes among older adults: a systematic review; Int.J. Behav. Med. (2010) 17:243-245 Psychological Determinants and Outcomes of Sedentary and Physical Activity Behaviours Yvette D. Miller Back

7   Public Health England, Everybody Active Every Day - an evidence based approach to physical activity (October 2014),p22 Back

8   Public Health England (IDH0063) para 23 Back

9   HM Government, Moving More, Living More, 2014, para 2.2 Back

10   Centre for Diet and Activity Research (IDH0069) para 3.1 Back

11   Public Health England, Everybody Active Every Day - an evidence based approach to physical activity (October 2014) p6 Back

12   Public Health England, Everybody Active Every Day - an evidence based approach to physical activity (October 2014), p5 Back

13   Department of Health (IDH0078) para 14 Back

14   Ramblers (IDH0014) para 6 Back

15   University of Bedfordshire (IDH0029) para 4 Back

16   Transport and Health Study Group (IDH0048) p1 Back

17   BMI = m/h2, where m is mass in kilograms and h is height in metres.  Back

18   Public Health England (IDH0063) para 21 Back

19   Public Health England (IDH0063) para 15 Back

20   Public Health England (IDH0063) paras 12-13 Back

21   Department of Health (IDH0078) para 16 Back

22   Ells, L.J., Hancock, C, Copley, V.R., Mead, E., Dinsdale, H., Kinra, S., Viner, R.M., Rutter, H. (2015) Prevalence of severe childhood obesity in England: 2006-2013, Arch Dis Child doi:10.1136/archdischild-2014-307036  Back

23   Public Health England (IDH0063) para 17 Back

24   Public Health England (IDH0063) para 18, para 20 Back

25   Further information can be found at and Back

26   UK Faculty of Public Health (IDH0083) p2 Back

27   Local Government Association (IDH0022) para 25 Back

28   Royal College of Physicians (IDH0043) para 2 Back

29   Centre for Diet and Activity Research (IDH0069), Executive Summary Back

30   Department of Health (IDH0078) para 13 Back

31   Ekelund, U et al. Physical activity and all-cause mortality across levels of overall and abdominal adiposity in European men and women: the European Prospective Investigation into Cancer and Nutrition Study (EPIC) American Journal of Clinical Nutrition; doi: 10.3945/ajcn.114.100065  Back

32   Q6 Back

33   Q283; for further information see Mora, S., Cook, N., Buring, J. E., Ridker, P. M., & Lee, I. M. (2007). Physical activity and reduced risk of cardiovascular events potential mediating mechanisms. Circulation, 116(19), 2110-2118.  Back

34   Q288 Back

35   Q295 Back

36   Academy of Medical Royal Colleges, Exercise: the miracle cure and the role of the doctor in promoting it , (February 2015), p5 Back

previous page contents next page

© Parliamentary copyright 2015
Prepared 25 March 2015