If you like king sized candy bars, from this point on you'll have to eat two regular sized bars instead of one big bar. Why? Michelle Obama has influenced Mars Candy to sign her "healthier America" agreement.
Regardless of the compromise Mars made with Michelle Obama, people will still eat more than 250 calories worth of candy bar. This situation is similar to the amount of liquids you can have on an airplane. You can't bring any liquids on board in a bottle larger than 3 ounces, so what do people do? They bring multiple 3 oz bottles filled with the same thing. Candy is no different. Smaller candy bars have always been available (and are despised by trick-or-treaters on Halloween) and people have been able to choose between small or large. Michelle Obama is simply limiting people's choice.