Years ago, I had a serious Diet Coke habit. But I thought of myself as just an occasional soda drinker. I thought I had it under control. And then I got a wake-up call.

It happened one day when I found myself lugging a week's worth of recycling down to the bin. The entire bag -- every last bottle and can -- had once contained diet soda. And, with a shock, I realized that I'd been in denial and that I drank way too much. So, I forced myself to go cold turkey the next day.

I've managed to stay on the wagon -- more or less -- for many years now. But every so often (on a hot day, after working in the garden, at the end of a bike ride) I indulge in an ice-cold diet soda.

But it may be time to swear off the stuff for good. I just read the latest news about a new study that shows that drinkers of diet and regular soda are 48 percent more likely to suffer from metabolic syndrome.

Of course, most of us know that sugary sodas are bad for us, but this study marks the first time that diet sodas are shown to be unhealthy and linked with a higher risk of heart disease.

Metabolic syndrome is a constellation of conditions -- excess abdominal fat, high blood pressure, high cholesterol, and high triglycerides -- which lead to a higher risk of heart disease and other chronic health problems.

But here's the strange part. Researchers aren't sure what exactly these results mean. It's unclear whether the soda ingredients are truly linked to heart disease and related conditions. More likely, say experts, is that soda affects our cravings and eating patterns. Or that drinking soda is an indicator of people who have poor eating habits in general.

According to an article in the Los Angeles Times, people who drank soda on a regular basis also had a higher-calorie diet comprised of more high-fat, low-fiber foods. They also led a more sedentary lifestyle.

An alternate theory is that sweet-tasting drinks lead to cravings or a desire for sweet foods. As of now, no one seems to know how soda, diet or otherwise, relates to metabolic syndrome.

To be on the safe, I'm going to stay on the wagon. And I guess I'll just have to resort to a beer on a hot day.