Sweetened drinks raise women's
risk for obesity, type 2 diabetes
Overweight, obesity, and type 2 diabetes — all of which increase
the risk for heart disease and other complications — have been
on the rise in the United States for nearly 30 years. During this same
period, our calorie intake from sugary drinks has increased 135%. Coincidence?
Probably not. Studies in children have found a strong association between
obesity and sweetened soft drinks, but similar data on adults was unavailable
for a time. A 2004 study from the Harvard School of Public Health helps
fill in the blanks, at least for women.
In the August 25, 2004, Journal of the American Medical Association ,
Harvard researchers reported that over an eight-year period, women who
consumed more soft drinks gained more weight. Specifically, they found
that women whose consumption rose from one drink or less per week to
one or more daily gained more than twice as much weight (averaging almost
18 pounds) as women who limited their consumption to no more than one
drink per week. One sugar-sweetened soft drink or more per day was also
associated with an 83% increase in risk for type 2 diabetes, compared
to an intake of less than one such drink per month. Similar consumption
of fruit-flavored punch (which can contain as little as 5% juice) doubled
the risk of type 2 diabetes. Diet sodas and true fruit juices did not
pose these risks.
The data came from the Nurses' Health Study II, in which researchers
have followed subjects for many years and carefully noted changes in
dietary habits. Women who increased their intake of sweetened soft drinks
also consumed more total calories, which suggests they did not eat less
solid food to compensate.
But the effect of soft drinks on weight gain and type 2 diabetes involves
more than extra calories. These beverages have a high glycemic index,
which means they are digested quickly, producing a brief spike in blood
sugar levels, and may not satisfy hunger for long. The Harvard study
suggests that sweetened drinks may even increase hunger. Consuming such
drinks can also lead to elevated insulin levels.
The fiber content of a true fruit juice such as orange juice gives it
a lower glycemic index than sugar-sweetened beverages. Real fruit juices
do have calories, but they also contain vitamins, minerals, and phytochemicals
that may play a role in improved metabolism or weight control. Foods
with a significant protein, fat, or fiber content also have a lower glycemic
index than soft drinks.
Another 2004 study — one on trends in beverage consumption from
1977 to 2001 — suggests a related cause of weight gain. Nutrition
experts at the University of North Carolina found that while Americans
consume more and more sweetened beverages, they are drinking less milk
at all ages ( American Journal of Preventive Medicine , October
2004). Milk has obvious nutritional value (which includes protein, calcium,
and vitamin D), and although it's not clear why, drinking milk has been
associated with reduced weight in a variety of studies.
In light of rising obesity rates and type 2 diabetes, we would do well
to cut down on our intake of sweetened soft drinks and juice drinks — admittedly
difficult when we're constantly exposed to super-sized temptations. Experts
estimate that most people could avoid gaining weight if they cut out
100 calories a day — an amount found in less than a can of soda.
What to do. Quench your thirst with water. If
you want a soft drink, stick to diet soda or flavored but unsweetened seltzers.
Get regular exercise — at least 30 minutes per day of physical activity
such as brisk walking or moderate bicycling. It not only burns extra calories
but also reduces the risk for type 2 diabetes.
December 2004 Update
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