7-Eleven
7-Eleven is giving away free Slurpee's frozen drinks Monday in celebration of the convenience store chain's birthday. Reuters

Those Slurpees that 7-11 stores across the country are handing out today might be free, but they will only serve to make you fatter and unhealthier in the long run,

According to a health blog in the Los Angeles Times, an 8-ounce Slurpee (only one size customers like) has about 70 calories – and no nutritional value whatsoever. Plus, like all pop drinks, it is loaded with sugar – about 17 grams; as well as 20 milligrams of caffeine.

However, be aware that Slurpees also come in much larger sizes -- 16, 22, 32 and even 44 ounce sizes (so one can multiply the amount of sugar carbs and caffeine in the larger servings).

According to LiveStrong.com, a 16-oz. Coca-Cola Classic Slurpee has 130 calories; a Fanta Orange Slurpee contains 132 calories; a Wicked Apple Slurpee contains 120 calories; and a Goji Berry Cherry Slurpee contains 134 calories.

In addition, according to CalorieKing, to burn urn the calories from drinking one Slurpee, you would need to walk for 18 minutes, jog for 7 minutes, swim for 5 minutes or cycle for 10 minutes.

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