Somewhere along the evolutionary path, it got into the human mind that feeding = showing affection and love. So, if your in-laws feel compelled to feed your dogs tidbits, provide them with healthy, low-calorie snacks that you can easily burn off with a daily walk.

For example, keep a bowl of plain boiled peas or carrots or apples in the kitchen. Should your father ever feel the need to feed the dogs, let him take a bit of a veggie or fruit and give it to the dogs. If you're lucky, the dogs will dislike the food. If not, so be it. In the meantime, ask your in-laws to go to the vet with you and have him explain the potential severity of the situation.

As they say, edumucation is the answer