Issue: 2015, Vol 1, No 2, Pages 41–79

Obesity Digest

Matt Capehorn

Matt Capehorn
Clinical Manager, Rotherham Institute for Obesity and Clinical Director, National Obesity Forum

Can you “outrun a bad diet”?

There was a recent article in the British Journal of Sports Medicine that gained a great deal of press coverage because it suggested that exercise was not a very good way to lose weight, and that “you cannot outrun a bad diet” (Malhotra et al, 2015). In many ways, I totally agree with this statement. I have long argued that exercise is an inefficient way of losing weight, unless you are doing a sufficient amount, with sufficient regularity (e.g. 30–60 minutes of aerobic style exercise three to five times per week), to raise your metabolic rate enough to induce a calorie deficit without necessarily needing a corresponding reduction in calorie intake. Simply encouraging our patients to walk the dog in the evening after our consultation will not be sufficient. They may walk the dog for a mile, but they probably only use up 100 kcal. If, as a reward, they then treat themselves to a chocolate bar for being so virtuous, that is an intake of more than 200 kcal, and the net effect is calorie gain and ultimately weight gain. It is in no way as effective as just reducing calorie intake.

However, this is only half of the story, and in many ways it gives the wrong impression of physical activity, especially when considered as part of a weight management programme. In my opinion, weight management programmes that include a physical activity component will achieve better outcomes than those that do not. Furthermore, why do we run weight management programmes? Is it to have our patients achieve a lower number when standing on the scales, or is it to make them more healthy? It is clearly the latter, and the evidence for physical activity improving markers of cardiometabolic health is overwhelming (Academy of Medical Royal Colleges, 2015).

There is a dose–response curve for the relationship between physical activity and risk of chronic disease. The more you exercise, the less likely you are to develop a chronic disease, and the unfit get proportionally greater benefit from a small increase in physical activity. The paper by Ekelund et al (summarised alongside) supports this evidence, showing that the greatest reductions in mortality risk were observed in the two groups with the lowest activity. A morbidly obese person who does a moderate to high amount of physical activity has a lower risk of cardiovascular mortality than someone with a healthy BMI who does little or no physical activity (Church et al, 2005). The article by Nicklas et al reviewed on the next page demonstrates that resistance training improves body composition, muscle strength and physical function, and supports the use of it regardless of whether calorie restriction is part of the intended treatment or not.

Anyone can exercise. Even wheelchairbound patients and the severely disabled can be found appropriate exercises if supported by an appropriate therapist, and a tailored approach can significantly impact long-term engagement with physical activity (Walker et al, 2012). Yes, we should accept the limitations of physical activity as an isolated intervention for weight loss, but let’s not lose sight of the overall picture; we should still include it in our weight management programmes.

Click here to read the article summaries

References from commentary

Academy of Medical Royal Colleges (2015) Exercise: The Miracle Cure and the Role of the Doctor in Promoting It. AMRC, London. Available at: http://bit.ly/1KzMWHE (accessed 10.07.15)

Church TS, LaMonte MJ, Barlow CE, Blair SN (2005) Cardiorespiratory fitness and body mass index as predictors of cardiovascular disease mortality among men with diabetes. Arch Intern Med 165: 2114–20

Malhotra A, Noakes T, Phinney S (2015) It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet. Br J Sports Med 22 Apr [Epub ahead of print] Walker L, Kaill A, Capehorn MS (2012)

Patient retention in a primary care MDT initiated physical activity programme. Presented at: Lightening the Load: What Works in Primary Care? (poster). London, 28 March

Ekelund U, Ward HA, Norat T et al (2015) 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). Am J Clin Nutr 101: 613–21

Nicklas BJ, Chmelo E, Delbono O et al (2015) Effects of resistance training with and without caloric restriction on physical function and mobility in overweight and obese older adults: a randomized controlled trial. Am J Clin Nutr 101: 991–9

Legler J, Fletcher T, Govarts E et al (2015) Obesity, diabetes, and associated costs of exposure to endocrine-disrupting chemicals in the European Union. J Clin Endocrinol Metab 100: 1278–88

Fatima Y, Doi SA, Mamun AA (2015) Longitudinal impact of sleep on overweight and obesity in children and adolescents: a systematic review and bias-adjusted meta-analysis. Obes Rev 16: 137–49

Johansson K, Cnattingius S, Näslund I et al (2015) Outcomes of pregnancy after bariatric surgery. N Engl J Med 372: 814–24