It was forecasted that 51% of the US population would be clinically obese by 2013.1 Currently almost 2/3 of Americans are overweight. Childhood obesity has tripled in recent years meaning that almost 20% of youths aged between 12 and 19 are overweight. "Alarmingly, results of studies have shown that more than 70% of children who are overweight will grow up to be adults who are overweight".1 The U.S. may be in the midst of raising the first generation since the nation’s founding, that will have a shorter predicted lifespan than that of the previous generation.1
THE FOOD INDUSTRY BLAMES INACTIVITY, CITING THAT WE JUST NEED TO MOVE MORE. BUT WHAT IS THE ROLE OF EXERCISE IN THE TREATMENT OF OBESITY?THERE IS CONSIDERABLE DEBATE IN CURRENT MEDICAL LITERATURE QUESTIONING IF PHYSICAL ACTIVITY HAS ANY ROLE WHATSOEVER TO PLAY IN THE EPIDEMIC OF OBESITY THAT HAS SWEPT THE GLOBE SINCE THE 1980S.2 THE INCREASE IN CALORIES PER PERSON IS MORE THAN SUFFICIENT TO EXPLAIN THE U.S. EPIDEMIC OF OBESITY.3 IN FACT, IF ANYTHING, THE LEVEL OF PHYSICAL ACTIVITY OVER THE LAST FEW DECADES HAS ACTUALLY GONE UP IN BOTH EUROPE AND NORTH AMERICA.4
This has important policy implications. Whereas on-going efforts are needed to increase physical activity levels in the population, the priorities for reversing the obesity epidemic should focus on energy intake by addressing the obesogenic food environment drivers of the current energy consumption.3
To support a healthy return to the body weights reflected in the 1970s and reverse these negative effects, it would mean calories per day per child would amount to 350kcal and 500Kcal per adult. Alternatively, compensatory increases in physical activity, around 100 to 150 minutes of extra walking would achieve similar results.3 Public health advocates have been experimenting with this kind of information by indicating on menus the equivalent amount of exercise to calories highlighting the number of miles needed to walk in order to burn those calories off, this appeared to be an effective way to influence the selection of lower calorie meals.5
Results from many studies have shown that exercise makes a small indent on controlling body weight (around 3% of initial body weight)1, but even that small indent can make a difference to the overall weight of the population. In the United States a 1% population-wide decrease in BMI would prevent more than 2 million cases of diabetes, 1.5 million cases of heart disease, and up to 127K cases of cancer.6
SO WHY DON’T WE LOSE MORE WEIGHT FROM EXERCISE?
It seems that we don’t do enough physical activity or at the correct intensity. A smaller magnitude of weight loss is observed due to low doses of prescribed exercise and energy expenditures.7 We often underestimate the amount of calories we burn through physical activity, and this does not balance with the calorie intake.8
In conclusion, choosing healthier lower calorie food options and continued daily physical activity are needed to sustain weight loss which in turn, helps to achieve changes in our body composition and keeps us healthier and ailment free on the inside.
- The role of exercise in the treatment of obesity. Laskowski ER. PM R. 2012 Nov.
- Energy Balance and Obesity. James O. Hill, et al. Circulation. 2012 Jul.
- Increased food energy supply is more than sufficient to explain the US epidemic of obesity. Swinburn B, et al. Am J Clin Nutr. 2009 Dec.
- Physical activity energy expenditure has not declined since the 1980s and matches energy expenditures of wild mammals. Westerterp KR, Speakman JR. Int J Obes (Lond). 2008 Aug.
- Potential effect of physical activity based menu labels on the calorie content of selected fast food meals. Sunaina Dowray, Jonas J. Swartz, Danielle Braxton, Anthony J. Viera. Appetite, Volume 66, 1 July 2013, Pages 89.
- Health and economic burden of the projected obesity trends in the USA and the UK. Wang YC, et al. Lancet. 2011 Aug.
- Why do individuals not lose more weight from an exercise intervention at a defined dose? An energy balance analysis. D. M. Thomas, et al. "Obes Rev. 2012 Oct.
- Myths, presumptions, and facts about obesity. Casazza K, et al. N Engl J Med. 2013 Jan.