Lifestyle Medicine and Prevention: Why the Small Things You Do Every Day Matter
I spent 20 years in health research across academia and the charity sector, helping to develop new treatments for existing chronic diseases like cancer and stroke. Whatever the area I was working in, a common thread kept resurfacing, that many chronic diseases are linked to things people have some ability to change.
One of the projects that shaped my thinking most was a programme of nutrition and physical activity for people newly diagnosed with cancer. We now know that with the right kind of support around nutrition and physical activity, rates of recurrence are significantly reduced, people do better on treatment, have few side effects and spend less time in hospital. It was this work that ultimately led me to re-train as a health and lifestyle coach and set up my coaching business.
In this post I explain how much disease may be preventable, and what the evidence does and does not tell us and how health and lifestyle coaching in critical in helping people to embed new habits when moving towards a healthier lifestyle.
The Scale of the Problem
The World Health Organization (WHO) reports that noncommunicable diseases (NCDs), the long-term conditions such as heart disease, cancer, chronic respiratory disease and diabetes, killed at least 43 million people in 2021. That is about 75% of deaths worldwide, excluding those related to the pandemic. Around 18 million of those deaths happened before the age of 70.
Cardiovascular disease accounts for the most NCD deaths (at least 19 million), followed by cancers (about 10 million), chronic respiratory diseases (about 4 million) and diabetes (over 2 million, including kidney disease caused by diabetes).
WHO describes NCDs as the result of a combination of genetic, physiological, environmental and behavioural factors. It names tobacco use, physical inactivity, harmful alcohol use, unhealthy diets and air pollution as factors that raise risk. So lifestyle is not the whole story, and not everything is a personal choice, but it is a significant part of the picture, and it is the part we can influence most directly.
What is lifestyle medicine?
The British Society of Lifestyle Medicine (BSLM) describes lifestyle medicine as evidence-based clinical care that supports behaviour change through person-centred techniques. It focuses on six pillars:
healthy eating
physical activity
restorative sleep
mental wellbeing
healthy relationships
minimising harmful substances
Lifestyle medicine is not an alternative to medical care, but rather works alongside it. What sets it apart is the emphasis on behaviour change. Telling someone what a healthy lifestyle looks like is the easy part. Helping them build it into a busy life is the harder part, and it is where most people need support.
How much disease is preventable?
Cancer. A Cancer Research UK analysis published in the British Journal of Cancer in 2018 estimated that 37.7% of UK cancer cases in 2015 were attributable to known, modifiable risk factors. That is around 135,500 cases a year. Smoking was the largest contributor (15.1% of cases), and overweight and obesity came second (6.3%).
Type 2 diabetes. The Diabetes Prevention Program, a large US randomised trial published in the New England Journal of Medicine in 2002, enrolled 3,234 adults at high risk of type 2 diabetes. Those assigned to a lifestyle programme, with goals of at least 7% weight loss and at least 150 minutes of physical activity a week, had a 58% lower incidence of diabetes than the placebo group over an average of almost three years. Metformin reduced incidence by 31%.
Heart disease and stroke. Two large international studies looked at how much of the risk of these conditions is linked to modifiable factors. INTERHEART, a case-control study across 52 countries published in The Lancet in 2004, found that nine risk factors together accounted for 90% of the population attributable risk of a first heart attack in men and 94% in women. The nine were abnormal blood lipids, smoking, high blood pressure, diabetes, abdominal obesity, psychosocial factors, daily fruit and vegetable intake, alcohol, and regular physical activity. INTERSTROKE, a similar study across 32 countries published in The Lancet in 2016, found that ten modifiable risk factors together were associated with 90.7% of the population attributable risk for all stroke. High blood pressure was the single largest contributor.
Dementia. The 2024 report of the Lancet standing Commission on dementia prevention, intervention and care identified 14 potentially modifiable risk factors across the life course. These were lower education, hearing loss, high LDL cholesterol, depression, head injury, physical inactivity, diabetes, smoking, excessive alcohol, high blood pressure, obesity, social isolation, air pollution and untreated vision loss. The Commission estimated that around 45% of dementia cases could potentially be prevented or delayed if all 14 were eliminated. Several of these map directly onto the pillars of lifestyle medicine, including activity, alcohol, mental wellbeing and relationships.
It is important to not that 45% is a theoretical upper limit. The calculation assumes that the risk factors are causal and can be eliminated, and some of them, such as education and air pollution, are shaped by society and policy more so than by personal choice.
COPD. WHO reports that tobacco smoking accounts for over 70% of COPD cases in high-income countries, and 30 to 40% in low- and middle-income countries, where household air pollution is also a major risk factor. This is a strong prevention story, though it is about smoking and air quality more than the other lifestyle pillars.
I also find it interesting how often the same factors recur. Smoking appears in the risk lists for cancer, heart disease, dementia and COPD, and physical inactivity, high blood pressure and excess weight appear across several of them. This overlap is one reason lifestyle medicine looks at the whole person rather than one condition at a time.
Lifestyle also matters after a diagnosis
Lifestyle does not stop mattering once a diagnosis has been made. For several long-term conditions, the evidence suggests that physical activity and nutrition can improve how people feel and function, and in some cases how the condition itself behaves. Here is what the research shows for a selection of them.
Cancer. The 2019 international consensus statement on exercise for cancer survivors, convened by the American College of Sports Medicine, points out that people living with cancer often experience declines in physical functioning and quality of life, and face a higher risk of recurrence and of death from any cause than people without cancer. It concluded that exercise training is generally safe for cancer survivors and that every survivor should avoid inactivity. It also found enough evidence to conclude that specific doses of aerobic exercise, resistance training, or both could improve anxiety, depressive symptoms, fatigue, physical functioning and health-related quality of life. The authors noted that the picture for other outcomes, such as nerve damage from treatment (peripheral neuropathy) and cognitive function, remains uncertain.
Research has also looked at whether exercise after a diagnosis is linked to outcomes such as recurrence and survival. A 2017 systematic review by Cormie and colleagues in Epidemiologic Reviews examined 100 studies of people who exercised after a cancer diagnosis. It found that, compared with patients who did little or no exercise, those who exercised had a lower relative risk of cancer death and recurrence, and experienced fewer or less severe treatment-related side effects. The authors concluded that exercise is an important adjunct therapy in cancer care. A 2022 study of women with breast cancer, published in the Irish Journal of Medical Science (Akdeniz and colleagues), asked patients about their exercise habits in an outpatient clinic. Those who exercised had a 58% lower risk of relapse than inactive patients, and a lower risk of death too. Notably, the benefit was also seen at modest levels of activity, such as exercising on between one and five days a week.
Heart disease. A 2021 Cochrane review examined exercise-based cardiac rehabilitation for people who had had a heart attack, bypass surgery or a stent, or who had angina or coronary artery disease. It concluded that this type of rehabilitation provides important benefits, including a lower risk of heart attack, a likely small reduction in death from any cause, a large reduction in hospital admissions and better quality of life up to 12 months. Over longer follow-up, the benefits may include fewer deaths from cardiovascular disease.
Type 2 diabetes. The UK DiRECT trial tested a structured weight management programme, which included a low-calorie liquid diet phase, delivered in routine GP practices to people with type 2 diabetes. Its investigators describe it as the first trial to show that remission is possible through a dietary programme in primary care: 46% of the intervention group were in remission at one year and 36% at two years. The five-year follow-up, published in The Lancet Diabetes & Endocrinology in 2024, found that of those in remission at the end of year two, 26% were still in remission at year five. The lesson is both encouraging and honest. Remission was possible, but keeping weight off over the long term takes ongoing support.
Depression. A 2024 systematic review and network meta-analysis in The BMJ pooled 218 randomised trials involving 14,170 people with depression. Walking or jogging, yoga and strength training each produced moderate reductions in depressive symptoms compared with active control conditions, dance showed larger reductions, and benefits tended to be greater with more vigorous exercise. The authors concluded that these forms of exercise could be considered alongside psychotherapy and antidepressants as core treatments.
Across these conditions the pattern is similar. Movement and nutrition can improve how people feel and function, and in some conditions the course of the disease itself. But the right type and amount of activity or diet depends on the diagnosis, the treatment, side effects and any other health conditions. The key phrase is adjusted to the individual. Anyone living with cancer, heart disease, diabetes or depression should discuss activity and nutrition with their care team before making significant changes, especially if they take medication that may need reviewing as their health changes.
Why knowing is not enough
Most of the people I speak to are intelligent and well informed. They know movement, sleep and food matter when it comes to their long term health. The hard part isn’t knowing what to do but how to actually do it, and keep doing it.
It is worth noting that in the Diabetes Prevention Program's lifestyle group, participants received intensive training in diet, exercise and behaviour change. Similarly with the cancer rehab programmes, participants were supported through a programme of nutrition and physical activity, not just told to eat well and move more. This all suggests that the support around the advice matters just as much, if not more that the advice itself.
This is where a health coach can help. A good coach does not hand you another list of rules, they help you turn a broad goal such as "move more" into a specific action that fits your week, for example a 15-minute walk after lunch on three days. They help you spot what gets in the way, whether that is a late meeting, travel or tiredness, and plan around it in advance. Regular check-ins add accountability, so a missed week becomes useful information rather than a reason to stop, and the plan can be adjusted as life changes. Coaching sits alongside, not instead of, the care you receive from your GP or healthcare team, but it is the missing piece that fills the gap between knowing and doing.
Where to start
So you know what it is you should be doing, but how do you move from there to taking action towards those healthier habits? Here’s a few simple suggestions:
Choose one pillar and one small action. Trying to overhaul everything at once is a common reason people give up. A walk after lunch is easier to keep up than deciding to overhaul your diet and hit the gym 5 times a week. Start by making the smallest, easiest change you can make and do it consistently.
Talk to your GP or practice nurse, especially if you have a diagnosis, take medication or are about to make big changes. Lifestyle change should work with your medical care.
Find support. Whether it is a friend, a group or a coach, accountability makes a habit easier to keep.
If you want some more specific pointers, try my free Health Score quiz. It only takes 5 minutes and might help to point you in the right direction.
References
World Health Organization. Noncommunicable diseases fact sheet (updated 25 September 2025). https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases
British Society of Lifestyle Medicine. About us / What is lifestyle medicine? https://bslm.org.uk/about/about-us/
Brown K et al. Cancer Research UK analysis of cancers attributable to modifiable risk factors in the UK in 2015. British Journal of Cancer, 2018. https://pubmed.ncbi.nlm.nih.gov/29567982/
Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346(6):393-403. https://pubmed.ncbi.nlm.nih.gov/11832527/
Campbell KL, Winters-Stone KM, Wiskemann J, May AM, et al. Exercise guidelines for cancer survivors: consensus statement from international multidisciplinary roundtable. Med Sci Sports Exerc 2019;51(11):2375-2390. https://pubmed.ncbi.nlm.nih.gov/31626055/
Yusuf S et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet 2004;364(9438):937-952. https://pubmed.ncbi.nlm.nih.gov/15364185/
O'Donnell et al. Global and regional effects of potentially modifiable risk factors associated with acute stroke in 32 countries (INTERSTROKE): a case-control study. Lancet 2016;388(10046):761-775. doi:10.1016/S0140-6736(16)30506-2
Livingston G et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet 2024;404(10452):572-628.
World Health Organization. Chronic obstructive pulmonary disease (COPD) fact sheet. https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(COPD)
Dibben G et al. Exercise-based cardiac rehabilitation for coronary heart disease. Cochrane Database Syst Rev2021;11(11):CD001800. https://pubmed.ncbi.nlm.nih.gov/34741536/
Lean MEJ et al. 5-year follow-up of the randomised Diabetes Remission Clinical Trial (DiRECT) of continued support for weight loss maintenance in the UK: an extension study. Lancet Diabetes Endocrinol 2024. doi:10.1016/S2213-8587(23)00385-6. Press summary: https://www.ncl.ac.uk/press/articles/latest/2024/02/direct-extensionstudy/
Noetel M et al. Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials. BMJ 2024;384:e075847. doi:10.1136/bmj-2023-075847
Cormie P, Zopf EM, Zhang X, Schmitz KH. The impact of exercise on cancer mortality, recurrence, and treatment-related adverse effects. Epidemiol Rev 2017;39(1):71-92. https://pubmed.ncbi.nlm.nih.gov/28453622/
Akdeniz N, Kaplan MA, Küçüköner M, et al. The effect of exercise on disease-free survival and overall survival in patients with breast cancer. Ir J Med Sci 2022;191(4):1587-1597. https://pubmed.ncbi.nlm.nih.gov/34606055/