In one sentence, describe what the following article is about:

Have a target weight or body shape in mind. It is a common problem to overshoot the mark and turn a thin cat into a fat cat, which comes with a whole new set of health problems. This will help you recognize when it reaches an ideal weight. Body scoring is about feeling for your cat's ribs and backbone, to see how much fat covers the bones, and looking at the cat's body shape to recognize if it is over or under weight. The perfect cat should have ribs and a backbone that is easily felt, but without standing out through the fur. The cat should also have a slight waistline when viewed from above and the side, but without sharp angles. Healthy weight charts can easily be found online that illustrate and describe feline body scores, making it easier to analyze your cat's body. Alternatively your vet can weigh your cat and make an estimate of their desired target weight. Weigh the cat weekly at home and keep a record of its weigh-ins. They can assess your cat's health and make suggestions for any necessary treatments. In addition, your vet can take care of routine deworming. If your cat is healthy but underweight, make sure it is dewormed against both roundworms and tapeworms. Be sure to check whatever product you use is effective against both sorts of worms. Some common products, such as Stronghold (UK) Revolution (US) and off the shelf products such as Hartz once-a-month wormers, work against roundworms but NOT tapeworms. Speak to your vet about a multi-wormer containing praziquantel, in order to kill tapeworms as well. If your cat is older, runs around like a kitten, eats well, but is losing weight, be aware the cat may have a medical problem called hyperthyroidism. This involves the cat having high levels of thyroid hormone in the blood stream, which acts as a stimulant. The cat burns off calories quickly and eats loads to try and replace them. However, despite the cat's apparent good health, this stimulation puts pressure on the organs, including the heart and kidneys. Rather than trying to combat the problem by feeding the cat more, seek veterinary help and get the source problem corrected to preserve your pet's good health. The vet might tell you that your cat has anorexia. This means that it lacks the desire to eat. In this case, they may tell you to water down canned food and give it to your cat using an oral syringe. Ask your vet if they think this approach would help your cat bridge the gap until it is in better health.

Summary:
Know your cat's ideal weight. Learn how to body score your cat. Take your cat to the vet. Be aware that a greedy cat with a thin body indicates a problem.