How to make my lazy cats move?

I have two male cats from the same litter they are about six years old and both are fat about 25lbs each both are given the amount of dry food listed on the back of the bag and the brand of food was given to me by the vet but they are still fat I have plenty of toys for them to play with and a cat tree for them to climb but they refuse to play climb or even move I have a female as well and she is a year old she eats the same amount and plays all the time she is at the perfect weight and I know that is because she plays so how am I to get the males to play so that they will loose the weight and be healthy