The U.S. government's dietary guidelines released last year allow people to get as much as 25 percent of their calories from added sugars. If it's not immediately obvious why that's a bad idea, a new study spells it out.

All that sugar is the fastest way to put yourself at risk for heart disease -- and you can see the damage in just two weeks.

Forty-eight volunteers between the ages of 18 and 40 were asked to spend five weeks limiting added sugars to a single eight-ounce cup of fruit juice a day, bringing them all down to an equal level, sugar-wise.

Then, they were divided into three groups and given 25 percent of their daily calories from one of three types of sugar: glucose, fructose, or high-fructose corn syrup.

For the HFCS group, that's the equivalent of 3.7 cans of soda a day for women and 4.4 cans for men -- a lot of soda (and a lot of sugar), but still less than what you'll find in a "Double Gulp" at your local 7-11.

After two weeks on this government-approved sugar high, the volunteers who had been getting their calories from fructose and high-fructose corn syrup had significant bumps in their levels of deadly triglycerides as well as a rise in LDL cholesterol.

They even had more apolipoprotein-B, a protein linked to plaque in the arteries, according to the study that will appear this fall in the Journal of Clinical Endocrinology & Metabolism.

If that's what two weeks of all that sugar will do to you, imagine what'll happen to your body in two months, two years or two decades -- if you even make it that far.

The study also offers more proof that you don't have to eat fat to send your cholesterol levels through the roof. Sugar will do that for you all by itself. Natural fats, on the other hand, can actually help keep cholesterol levels under control as well as lower your blood pressure and blood sugar levels.

Yet the same government that wants you to eat more sugar is constantly urging you to avoid fat -- putting you on a collision course with diabetes, heart disease, and a premature demise.

The lesson here: No matter what Uncle Sam says, no amount of added sugars are an acceptable part of the diet.

I know, you can't always avoid them… and everyone is going to indulge here and there.

But as a daily ration? Forget it.