USA TODAYBurger King now has a Lucky Charms milkshake — a combo of childhood nostalgia, ice cream and enough sugar to test the luck of any leprechaun.Mixed together are vanilla soft-serve ice cream, syrup, Lucky Charms cereal and, of course, marshmallows. The U.S. Food and Drug Administration hasn't established how much sugar is OK to eat in a day, but it's safe to say this concoction's 107 grams of sugar would not be part of a balanced breakfast.Altogether, it has 740 calories, 17 grams of fat, 580 mg of sodium and 129 grams of carbohydrates. The cost: $2.99. It's available for a...…USA TODAYBurger King now has a Lucky Charms milkshake — a combo of childhood nostalgia, ice cream and enough sugar to test the luck of any leprechaun.Mixed together are vanilla soft-serve ice cream, syrup, Lucky Charms cereal and, of course, marshmallows. The U.S. Food and Drug Administration hasn't established how much sugar is OK to eat in a day, but it's safe to say this concoction's 107 grams of sugar would not be part of a balanced breakfast.Altogether, it has 740 calories, 17 grams of fat, 580 mg of sodium and 129 grams of carbohydrates. The cost: $2.99. It's available for a...WW…