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This section does not replicate the other information in this handbook but provides additional details or context most relevant to professionals.
Supporting lifestyle changes
Addressing your patient’s obesity with compassion, taking time to explore underlying contributors, and with guidance instead of judgment will build trust and cooperation. Most obese people know they are obese (but some do not, so be prepared for that conversation). Many people with obesity desperately want to lose weight but cannot manage it on their own.
Your active support is likely needed for your patients to make changes, as research shows that adherence is generally low, but interventions combined with support show more success.
- Adherence to physical activity, dietary, and multiple lifestyle behaviors recommendations was low among cancer survivors. Recent cancer survivors were relatively more adherent to WCRF/AICR recommendations compared to long-term survivors in a very large meta-analysis of 51 clinical trials.1Tollosa DN, Tavener M, Hure A, James EL. Adherence to multiple health behaviours in cancer survivors: a systematic review and meta-analysis. Journal of Cancer Survivorship. 2019 Jun;13(3):327-343.
- Physician referral to a weight management group, followed by ensuring the patient made an appointment and was offered follow-up, led to more weight loss at 12 months—2.43 kg (5.35 lb) compared to 1.04 kg (2.3 lb)—than physician advice to the patient that their health would benefit from weight loss.2Aveyard P, Lewis A etal. Screening and brief intervention for obesity in primary care: a parallel, two-arm, randomised trial. Lancet. 2016 Nov 19;388(10059):2492-2500.
- A group-based behavioral intervention including both exercise and nutrition, supplemented with telephone counseling and tailored newsletters to support weight loss led to greater weight loss after both one and two years among breast cancer survivors compared to a less intensive control intervention.3Rock CL, Flatt SW et al. Results of the Exercise and Nutrition to Enhance Recovery and Good Health for You (ENERGY) trial: a behavioral weight loss intervention in overweight or obese breast cancer survivors. Journal of Clinical Oncology. 2015 Oct 1;33(28):3169-76.
- An intervention of three supervised exercise sessions per week and individualized dietary advice, supplemented by weekly nutrition seminars, for women with breast cancer treated 3–18 months previously led to smaller waist circumferences and waist-hip ratios, lower cholesterol and leptin, and a weak trend toward more weight loss compared to controls in a small RCT.4Scott E, Daley AJ et al. Effects of an exercise and hypocaloric healthy eating program on biomarkers associated with long-term prognosis after early-stage breast cancer: a randomized controlled trial. Cancer Causes & Control. 2013 Jan;24(1):181-91.
Approaching the topic with “we” messages instead of “you” messages can set a supportive tone:
- We need to work together to address your excess weight.
- Help me understand your barriers to losing weight.
- Let’s find a program that works for you.
Involving your patient in setting goals and making changes is both supportive and empowering:
- How far do you think you can walk each day? Can you increase that by 10% after two weeks?
- What kind of activity would you look forward to?
- What do you think are the biggest problem foods for you? How can you make a small change to start to fix that?
Some physicians have started walking clubs, inviting groups of patients to walk with them on their lunch hour once a week or more. Some offer an incentive of answering medical questions (but not specific to a patient’s condition). We realize that this is “over and above” what you may be able to provide, but perhaps you can be creative in finding small ways to offer support:
- A weekly email message of support and encouragement. This could be as brief as an inspirational quote, or as long as a newsletter with tips and recipes.
- Joining an online community with your patients to share successes, find encouragement with challenges, and bolster a sense of support.
For people who are underweight or at risk of unintentional weight loss, dietary counseling is important. “Get more calories, no matter where they come from” is not the best advice. Dietary counseling focused on health-promoting ways to increase calories is important.
See further specific guidance and recommendations for initiating and supporting lifestyle changes that can impact your patients’ body weight on these pages:
Resources for supporting weight loss
Resources for weight loss among people with cancer
Modes of action: obesity and angiogenesis
One study suggests at least one possible way weight loss in obese women may influence cancer behavior. A randomized control trial study compared the effects of dietary weight loss, exercise, or their combination on circulating levels of regulators of angiogenesis (new blood vessel creation to supply cancer cells) in a large sample of healthy, overweight or obese postmenopausal women. Weight loss reduced circulating angiogenic biomarkers. They “suggest that weight loss in overweight or obese postmenopausal women may reduce risk for cancer in part through altering angiogenesis.”5Duggan C, Tapsoba Jde D, Wang CY, McTiernan A. Dietary weight loss and exercise effects on serum biomarkers of angiogenesis in overweight postmenopausal women: a randomized controlled trial. Cancer Research; 76(14); 4226–35.
Preclinical evidence: obesity and immune function
Obesity induced by a high-fat diet impairs CD8+ T cell function in the tumor microenvironment of mice.6Ringel AE, Drijvers JM et al. Obesity shapes metabolism in the tumor microenvironment to suppress anti-tumor immunity. Cell. 2020 Dec 23;183(7):1848-1866.e26.
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