Debunking the notion that you can sweat away a bad diet


young man chooses between healthy food and junk food

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Some things you just can't run away from. It might seem like an unpleasant — not to mention unfair — truth but it seems like excess weight is probably one of them. According to an editorial published this week in the British Journal of Sports Medicine, it is an increase in the consumption of sugar and carbs — not a lack of physical activity — which is responsible for the surge in obesity in the West.


Mixed messages

It's time, the Journal  argues, to bust the myth that anyone — and that includes athletes — can just sweat away the problems of excess weight. The argument is that, as obesity levels have skyrocketed, the figures for physical activity have remained fairly constant. "This," say the authors, "places the blame for our expanding waistlines directly on the type and amount of calories consumed."

Although maintaining a routine of regular exercise plays a key role in avoiding serious diseases such as diabetes, heart disease, and dementia, "poor diet now generates more disease than physical inactivity, alcohol and smoking combined," they say. They suggest that a lack of understanding by doctors, policymakers and the media means "members of the public are drowned by an unhelpful message about maintaining a healthy weight through calorie counting, and many still wrongly believe that obesity is entirely due to lack of exercise." The evidence now suggests that up to 40 percent of those within a normal weight (BMI) range will none the less harbor harmful metabolic abnormalities typically associated with obesity.


Losing the halo

The authors describe the public relations tactics of the food industry as "chillingly similar to those of Big Tobacco," which deployed tactics of denial, doubt and confusion as well as "bent scientists" to convince the public that smoking was not linked to lung cancer. Their finger points at big industry players like Coca-Cola, who, they say, spent $3.3 billion in 2013 "pushing the message that 'all calories count.'" By associating their products with sports, the Journal  argues, companies are "suggesting it is ok to consume their drinks as long as you exercise. However, science tells us this is misleading and wrong." Fundamentally, it is the source of the calories that matters, they argue: "Sugar calories promote fat storage and hunger. Fat calories induce fullness or satiation."

Popular culture, the article argues, has a big hand in such issues. "Celebrity endorsements of sugary drinks and the association of junk food and sport[s] must end," they declare, adding that health clubs and gyms need to set an example by removing the sale of these products from their premises. One of the greatest dangers is what they describe as the "health halo" given to certain foods by advertisers and media gurus. "This manipulative marketing," they say, "sabotages effective government interventions such as the introduction of sugary drink taxes or then banning of junk food advertising. Such marketing increases commercial profit at the cost of population health."


Kicking carbs to the curb

The authors debate the legitimacy of ideas like "carbohydrate loading" — the idea that, because the body has a limited capacity to store the carbohydrates required for intense exercise, eating increased amounts before working out provides better results. They argue that studies show how a high-fat low-carbohydrate "induces very high rates of at oxidation during exercise (up to 1.5 g/min) — sufficient for most exercisers in most forms of exercise — without the need for added carbohydrate." Worse still, they say, athletes who follow very high-carbohydrate diets for many years significantly worsen their insulin resistance and so risk developing type-2 diabetes.

The authors call for a "change in the food environment" that would allow consumers a free choice about their options. Creating a situation where people default to healthy options "will have a far greater impact on population health than would counseling or education."The authors cite recent research that indicates how cutting down on dietary carbohydrate is the single most effective approach for reducing all the features of the metabolic syndrome and how it should be the primary strategy for treating diabetes, with benefits occurring even in the absence of weight loss.


Ignore the machine

The strongly worded editorial is bound to ruffle some feathers. Manufacturers, advertisers and media gurus all place a lot of store in the eat-now-sweat-later ethos. The authors, while supporting an active lifestyle, are confident of their position "Regular physical activity," they say, "reduces the risk of developing cardiovascular disease, type 2 diabetes, dementia and some cancers by at least 30%. However, physical activity does not promote weight loss."

They maintain that a fundamental change in our attitude toward food is the only sure way to fight the current diet and health problems society faces. "Healthy choice must become the easy choice," they say. "It's time to wind back the harms caused by the junk food industry's public relations machinery. Let's bust the myth of physical inactivity and obesity. You can't outrun a bad diet."