The results are in and they are impressive (particularly for those of us with fat cats who never lose an ounce). After two weeks of dieting, Jack is once again the biggest loser, with 1.56 pounds — or 9.4 percent — of his original body weight gone; in second is Minky, who has lost 7.6 percent of her body weight (1.13 pounds). All the eight cats have either continued to lose weight or remain the same.

What is the secret for those of us with fat cats?

Most cats should weigh between 9 and 12 pounds, says Dr. Donna Spector, Halo’s veterinary advisor who is conducting the fat cat weight loss challenge at Bideawee. Even if they are starting at 20 to 25 pounds, their ideal weight is likely monumentally lower. There are a few naturally larger and smaller breeds so ask your veterinarian if you need advice on determining your cats ideal weight.

To achieve weight loss to this range, cats need to be given two meals daily and the total calories need to be about 25% less than what a normal, non-obese 9 to 12 pound cat would need to eat to maintain a healthy weight in this range, says Dr. Spector.

Here is a quick guide:

If your cat should weigh 9 or 10 pounds, give her:
Morning: 3.5 ounces of canned chicken Spot’s Stew and 1 tablespoon Spot’s Stew dry Evening: 3.5 ounces of canned chicken Spot’s Stew

If your cat should weigh 12 pounds, give her:
Morning: 3.5 ounces of canned chicken Spot’s Stew and 1 tablespoon Spot’s Stew dry
Evening: 3.5 ounces of canned chicken Spot’s Stew and 1 tablespoon Spot’s Stew dry

If your cat should weigh 15 pounds, give her:
Morning: 3.5 ounces of canned chicken Spot’s Stew and 2 tablespoons Spot’s Stew dry
Evening: 3.5 ounces of canned chicken Spot’s Stew and 1 tablespoon Spot’s Stew dry

The dry foods can be used interchangeably as the calories are similar. Dr. Spector recommends the canned chicken Spot’s Stew because it has the lowest calories of our canned foods and is best for weight loss.

Monitor your cat’s progress with weekly weights. They should lose 1-2% of their original body weight every week. If they are losing slower than this, you will have to restrict calories further. If they are losing quicker than this, you will have to add a few calories back in.