BMJ: Time to bust myth that
anyone— including athletes—can outrun a bad diet Excess sugar and carbs, not physical inactivity, are
behind the surge in obesity, say experts in an editorial in the British Journal of
Sports Medicine published online today. Regular exercise is key to staving off serious
disease, such as diabetes, heart disease, and dementia, write the authors, but
our calorie laden diets now generate more ill health than physical inactivity,
alcohol, and smoking combined.
The evidence now suggests that up to 40% of those
within a normal weight (BMI) range will none the less harbour harmful metabolic
abnormalities typically associated with obesity.
But few people realise this, and many wrongly believe
that obesity is entirely due to lack of exercise, a perception that is firmly
rooted in corporate marketing, say the authors.
They describe the public relations tactics of the food
industry as “chillingly similar to those of Big Tobacco,” which deployed denial,
doubt, confusion and “bent scientists” to convince the public that smoking was
not linked to lung cancer.
“Celebrity
endorsements of sugary drinks and the association of junk food and sport 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. “The ‘health halo’
legitimisation of nutritionally deficient products is misleading and
unscientific,” they write.
Public
health messaging has unhelpfully focused on maintaining a ‘healthy weight’
through calorie counting, but it’s the source of the calories that matters,
they point out. “Sugar calories promote fat storage and hunger. Fat calories
induce fullness or satiation,” they write.
The
prevalence of diabetes increases 11-fold for every 150 additional sugar
calories consumed daily, compared with the equivalent amount of calories
consumed as fat, they say.
And the
evidence now suggests that carbs are no better, they add. Recent research
indicates that cutting down on dietary carbohydrate is the single most
effective approach for reducing all of the features of the metabolic syndrome
and should be the primary strategy for treating diabetes, with benefits
occurring even in the absence of weight loss.
Furthermore,
other research suggests that rather than carbohydrate loading ahead of intense
exercise, athletes would be better off adopting a high fat low carb diet,
particularly those who are already insulin resistant.
The
food environment needs to be changed so that people automatically make healthy
choices, suggest the authors. This “will have far greater impact on population
health than counselling or education. 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,” they conclude.