Key takeaways
- There is a strong link between body weight and the risk of developing cancer, as well as body weight and cancer coming back
- Eating a healthy, balanced diet and following guidelines for physical activity can help reduce cancer risk
- Losing weight as a side-effect of cancer or its treatment can have an impact on treatment and recovery
- Anxiety around food and activity after cancer is very common, and support from professionals can be beneficial
Cancer rates are increasing, and are highest in developed countries that have high rates of obesity. According to the World Cancer Research Fund (WCRF), there is strong evidence that being overweight or living with obesity throughout adulthood increases the risk of at least 12 different cancers. Research also shows that 13% of cancers worldwide are attributable to obesity. Body weight is not only associated with cancer risk, but also the risk of recurrence and cancer outcomes. The WCRF has created guidelines to help people understand how to reduce their cancer risk. The first of these is to keep your weight within a healthy range and avoid weight gain in adult life. In this article, three Perci professionals, registered dietitian Megan Pattwell, clinical exercise coach Nick Michell and lead cancer nurse specialist Rachel Rawson, share important information about cancer and body weight, and how to approach diet and activity for cancer prevention and during treatment.
The role of weight management for cancer prevention
“While we can’t completely eliminate the risk of getting cancer, we can take sensible steps towards reducing it. Maintaining a healthy weight is an important way to do this, and that means staying active and eating a balanced diet. Each meal should be as balanced as possible. Always include a quality lean protein (like chicken breast, mince, fish, beans or pulses), a complex starchy carbohydrate (like bread, pasta, rice or potatoes and opt for the whole grain versions if you can), and as many fruits and vegetables as you can get in. Good quality sources of dairy are important as they contain protein and important micronutrients. Plant-based alternatives are also good, as long as they are fortified.
For cancer prevention, look to limit the amount of red meat you eat, which has links with certain cancers, as well as limiting refined sugars, which are found in cakes, sweets, biscuits and soft drinks. Limit alcohol as much as possible – current guidance in the UK is 14 units per week. Food isn’t just fuel, but also important psychologically and socially, and should be enjoyed. My advice is to always eat in moderation and according to recommended portion sizes.”
– Megan Pattwell, Registered Dietitian
“An important aspect of cancer risk reduction is something called ‘insulin regulation’. Insulin is a hormone that’s released when there’s too much glucose (sugar) in the blood. Research shows that high insulin levels are linked to an increased risk of cancer. If you are overweight and have more fat tissue, you will have higher levels of insulin and an increased cancer risk. Regular exercise increases insulin sensitivity, which means your body will be more effective and efficient at lowering insulin levels. The more activity you do, the more you lower your body fat, your insulin levels and your cancer risk. This doesn’t have to be complicated. We should all be aiming for around 150 minutes of moderate activity a week, as well as strength sessions that activate the major muscle groups.”
– Nick Michell, Clinical Exercise Coach
Women, weight management and oestrogen
Being overweight or obese may affect the balance between the damage that happens to our DNA from outside factors, such as the environment, and how well we can deal with it. Having excess fat in our cells and tissues can act as a stress and lead to inflammation which can, over time, damage our DNA. Fat cells make oestrogen, a female hormone that can lead to some cells dividing and replicating at a quicker rate. As fat cells are the main source of oestrogen after the menopause, the more you have, the more oestrogen you have, which. in turn can lead to cancer.
– Rachel Rawson, Lead Cancer Nurse Specialist, Perci Health
The importance of weight management during cancer treatment
“Cancer can cause weight loss, as it can increase the body’s need for protein and calories. If this is the case and you don’t eat enough, you can begin to lose weight. Cancer treatment can cause side-effects including fatigue, nausea, pain, mouth ulcers and changes to bowel habit, which can all make eating and drinking a challenge. This can independently cause weight loss or increase the existing weight loss from the cancer itself, and a reduction in body weight may make cancer treatment less effective.
If you are losing weight or struggling to maintain your weight, eating more high-calorie, high-protein foods will help you to regain and maintain lost weight. It will also help you to maintain muscle mass, mobility and quality of life. I recommend increasing meat, fish, beans, pulses, dairy and dairy alternatives in your diet, and opting for full-fat versions of those products. People undergoing cancer treatment often find it helpful to eat little and often. Good snack options during treatment include cheese and crackers, hummus and pitta, and boiled eggs.”
– Megan Pattwell, Registered Dietitian
“Cancer treatment can lead to muscle wastage, which in turn can affect how treatment works. The solution is to maintain or build as much lean muscle mass as you can, before and during cancer treatment.
Cancer treatments vary and some can cause more side-effects than others. The key to exercising during chemotherapy is to be aware of its cycles. Usually, a few days after treatment you’ll need to rest. You can introduce light activity when you start to feel better, and then increase it towards the end of the cycle and between treatment cycles. Working with a clinical exercise coach can help you to match your level of activity to your symptoms, and to exercise safely. If your primary side-effect is fatigue, it’s important to move as much as you can. However, be aware of how your body is feeling, if something doesn’t feel right, let your treatment team know.”
– Nick Michell, Clinical Exercise Coach
The importance of weight management after cancer
“When it comes to diet and weight management after cancer, many of the same guidelines apply as with preventing cancer. However, after treatment, returning to eating a healthy, balanced diet can be challenging. It’s easy to get overwhelmed, so instead of making changes all in one go, try to focus on one or two smaller goals at a time.
I see lots of clients who experience anxiety around food: people who have eaten a healthy diet and still developed cancer, and people who worry that their less healthy diet might have caused their cancer. There are also lots of claims around food and cancer that lack evidence. These can cause anxiety, and following restrictive diets can make you unwell. Tackling these challenges can be tricky and this is part of my work. The focus should always be on what good things you can include in your diet, to nourish your body’s healthy cells, rather than what you can restrict.”
– Megan Pattwell, Registered Dietitian
“There is increasing evidence that people who are active after a cancer diagnosis have a better chance of survival. When you’ve come through something as challenging as cancer, it’s natural to want to make lifestyle changes, and I often see people start to over-exercise. Even if you have maintained your fitness during treatment it’s important to take things slowly. I always advise people to find things they really enjoy. Before or during treatment, we’re usually in the gym because that’s what’s needed, but afterwards, it’s perfectly okay to find other activities that have the same benefits. Gardening, walking, dancing – as long as you’re physically moving your body and maintaining a healthy body weight, you’re on the right track. You don’t have to run a marathon, unless you want to of course. The key to success is consistency.”
– Nick Michell, Clinical Exercise Coach
Making lifestyle changes can be challenging. Our Cancer Nurse Specialists can talk you through cancer risk factors, and side-effects associated with treatment, as well as refer you to other Perci professionals, like registered dietitians and clinical exercise specialists, who can offer support.
While we have ensured that every article is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns, please talk to one of our healthcare professionals or your primary healthcare team.
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