Just in time for the Summer Olympics in London, a top science journal has issued a blistering
indictment of the sports drink industry. According to the series of reports from
BMJ (formerly
British Medical Journal),
the makers of drinks like Gatorade and Powerade have spent millions in
research and marketing in recent decades to persuade sports and medical
professionals, not to mention the rest of us suckers, that a primal
instinct—the sensation of thirst—is an unreliable guide for deciding
when to drink. We've also been battered with the notion that boring old
water is just not good enough for preventing dehydration.
I've been as susceptible to this scam as anyone else; I knew, or
thought I knew, that if I'm thirsty after my half-hour go-round on the
elliptical trainer, it means I was underhydrated to begin with. So for
years I've been trying to remember to ignore my lack of thirst and make
myself drink before working out. Not any more.
The
BMJ's package of seven papers on sports performance
products packs a collective wallop. The centerpiece is a well-reported
investigation of the long-standing financial ties between the makers of
Gatorade (PepsiCo), Powerade (Coca-Cola, an official Olympic sponsor),
and Lucozaid (GlaxoSmithKline) with sports associations, medical groups,
and academic researchers. It should come as no great surprise that the
findings and recommendations that have emerged through these
affiliations have tended to include alarming warnings about dehydration
and electrolyte imbalance—warnings that conveniently promote the
financial interests of the corporate sponsors.
And who knew there was something called the
Gatorade Sports Science Institute? According to the
BMJ
investigation, "one of GSSI's greatest successes was to undermine the
idea that the body has a perfectly good homeostatic mechanism for
detecting and responding to dehydration—thirst." The article quotes the
institute's director as having declared, based on little reliable
evidence, that "the human thirst mechanism is an inaccurate short-term
indicator of fluid needs."
Another study in the
BMJ package finds that the European
Food Safety Authority, which is authorized to assess health claims in
food labels and ads, has relied on a seriously flawed review
process
in approving statements related to sports drinks. A third study reports
that hundreds of performance claims made on websites about sports
products, including nutritional supplements and training equipment as
well as drinks, are largely based on questionable data, and sometimes no
apparent data at all. One overall theme emerging from the various
papers is that much of the research cited was conducted with elite and
endurance athletes, who have specific nutritional and training needs;
any such findings, however, should not be presumed to hold for the vast
majority of those who engage in physical activity.
Critics have long blasted sports drinks as being loaded with calories
and unnecessary ingredients. (Not to mention concerns about the
environmental costs of producing, shipping, and discarding all those
millions of plastic bottles.) Yet the product category represents a
lucrative and growing market, with US sales of about $1.6 billion a
year, according to the
BMJ. In fact, Powerade is the official
sports drink of the London Olympics, and Coca-Cola is hyping the brand
with a campaign featuring top-tier athletes.
The BMJ papers address two related but distinct questions: Should
people who exercise seek to proactively replace fluids lost, or can
they rely on thirst to guide them during and after physical activity?
And when they rehydrate, do they need all the salts, sugars, and other
ingredients dumped into sports drinks, or is water fine? The correct
answers are: best to rely on thirst, and water is fine. All that stuff
about replacing electrolytes and so on you've been hearing all these
years? Never mind! The evidence doesn't support it.
Overhydration presents a far greater risk of serious complications, and even death, than dehydration.
In a
commentary
accompanying the investigations in the journal, Timothy Noakes, chair
of sports science at the University of Cape Town, points out that
overhydration presents a far greater risk of serious complications, and
even death, than dehydration. Moreover, he notes, the notion that fluid
and electrolytes must be immediately replaced is based on a fundamental
misunderstanding of our past as "long distance persistence hunters" in
arid regions of Africa.
"Humans do not regulate fluid balance on a moment to moment basis,"
Noakes writes. "Because of our evolutionary history, we are delayed
drinkers and correct the fluid deficits generated by exercise at, for
example, the next meal, when the electrolyte (principally sodium but
also potassium) deficits are also corrected…People optimize their
hydration status by drinking according to the dictates of thirst. Over
the past 40 years humans have been misled—mainly by the marketing
departments of companies selling sports drinks—to believe that they need
to drink to stay 'ahead of thirst' to be optimally hydrated."
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