Mounting evidence links sugary drink intake with rising obesity rates, but it's only recently that researchers started to sound the alarm: Sugary drinks not only cause obesity - which any food in excess will do - but may also act on our body in a uniquely harmful way. Soda intake is associated with heart disease type 2 diabetes and hypertension independent of obesity - now, how do we explain that?
Some blame the rapid and super-sized influx of refined sugar in sugary drinks, especially the fructose component of their sweeteners, and studies have shown a direct adverse effect of high fructose intake on fat metabolism and inflammation.
Sugar's not so sweet effects
A study from the University of California at Davis showed that drinking 25 percent of daily calories (which is quite a lot) in fructose for 10 weeks increased triglycerides and cholesterol, caused insulin resistance belly fat accumulation.
A recent study found that even moderate consumption of sugary drinks led to measurable undesirable effects after just three weeks: Belly fat accumulated, fasting glucose levels and inflammation markers rose, and the lipid profile changed when volunteers drank what amounted to just 1 can of soda a day. Again fructose performed worse than glucose, but all sugary drinks had harmful effects, and it's only in the lab that people can get pure glucose. In our marketplace drinks are usually sweetened with sucrose (table sugar) or high fructose corn syrup (HFCS); both types of sweeteners are a combination of the simple sugars glucose and fructose, and all popular sugary drinks contain fructose.
To add to this body of evidence, a new study in the journal Obesity examines the association between sugary drinks and diet beverages and the accumulation of fat, especially belly or visceral fat - the fat inside the abdomen that is active metabolically and associated with heart disease and diabetes.
The study, led by Andrew Odegaard, followed almost 800 healthy men and women, and looked at beverage consumption (assessed by questionnaires) and fat accumulation, measured by waist circumference, weight, BMI and the proportion of belly fat to under-the-skin fat, which was evaluated by MRI (Magnetic Resonance Imaging).
Here's what the researchers found:
· Drinking more sugary drinks was associated with significantly more belly fat and wider waistlines
· Drinking more diet drinks (sweetened by non-caloric sweeteners) was associated with a larger waist circumference, higher BMI and more total fat, but not with increased visceral or belly fat.
The sugary drinks - belly fat connection
This study adds another small piece to the puzzle: sugary drinks are associated with obesity. Sugary drinks are also associated with insulin resistance, type 2 diabetes and heart disease, which are all diseases associated with abdominal (visceral fat). If drinking sugar leads to preferred accumulation of fat in the belly that may explain why sugary drinks stand apart as the most important link between a food and obesity and disease.
What about diet soda?
Diet beverages are calorie free, and were thought to be the perfect answer for those seeking sweetness without the caloric price tag. However, the jury's still out regarding artificial sweeteners' effect on weight: Short-term clinical trials show that artificially-sweetened beverages may produce short-term weight loss when they replace sugary drinks, however the few long-term studies available, which should be interpreted cautiously, show a surprising dose response correlation between consuming diet drinks and the development of obesity, and a correlation between the consumption of diet drinks and the metabolic syndrome and type 2 diabetes.
This new study's results join those that find that diet drinks are linked with weight gain. Finding that the diet-soda-extra-fat is not in the worst place - larger waists and BMI related to diet-beverages were not because of fat deposited in the belly, but rather under the skin - is a small consolation.
Add to that the concern around synthetic chemicals in artificial sweeteners, the habituation to intense sweetness, and the false signals of sweetness without calories sends to our body and mind, you'll see why many health professionals don't see diet drinks as the solution to our sweet obsession.
Full disclosure: I'm vice president of product development for Herbal Water, where we make organic herb-infused waters that have zero calories and no sugar or artificial ingredients. I'm also a pediatrician and have been promoting good nutrition and healthy lifestyle for many years.