Are you tired of hitting the gym every day without seeing any changes on the scale? Exercise is a good thing, but new research proves that exercise alone won't help you lose weight. In other words, you can run all you want, but physical activity alone won't do the trick.

The obesity study with the deflating title, which was compiled by a team of British cardiologists and published in the British Journal of Sports Medicine, found that diet is key when it comes to losing weight. The researchers are hoping to "bust the myth" that exercise can stop obesity.

"In the past 30 years, as obesity has rocketed, there has been little change in physical activity levels in the Western population," the study's authors write. "This places the blame for our expanding waist lines directly on the type and amount of calories consumed. Our calorie-laden diets now generate more ill health than physical inactivity, alcohol, and smoking combined."

According to the World Health Organization, more than 600 million people around the world are considered obese, a number that has doubled since the 1980s. The authors contend that sugar and carbs are to blame for the world's rise in obesity, not our inactivity.

But to really lose weight, they suggest not just calorie counting, but paying attention to where those calories are coming from. For example, drinking one 150-calorie soda is 11 times more likely to increase a person's risk for type 2 diabetes, compared to 150 calories obtained from fat or protein. According to researchers, these results were independent of a person's weight and physical activity level.

That's not to say that exercise is a bad thing. Even without dietary changes, exercise can help reduce a person's risk for heart disease, dementia, certain types of cancer, and type 2 diabetes. But without a healthy diet, it won't help you break the obesity cycle.  

So run all you want — it's still very good for you — but unless you change your diet, the scale is not going to budge.

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