There aren't too many things more upsetting than viewing a malnourished, underweight cat. Many cats that are underweight suffer from deadly illnesses and diseases, but more often than not suffer from a severe lack of intake of needed food and nutrients. Adding weight to an underweight cat takes caution and care, as cats that consume food too rapidly can upset their stomach lining and place them at an increased risk of regurgitating or vomiting the food. Learning how to add weight to very underweight cats safely and cautiously is important if you want to keep the cat as healthy as possible.
Take the cat to the veterinarian. This will help rule out common diseases and ailments, like worm infestations or rotten teeth, that often prevent cats from eating or consuming required food and nutrients.
Purchase commercial brand cat food. The Virginia-Maryland Regional College of Veterinary Medicine recommends using a commercial cat food brand, as that is the most convenient method of ensuring a cat receives correct proportions of proteins, fats, carbohydrates, vitamins, minerals and water needed for proper nutrition. You can purchase well balanced and nutritious commercial brand cat food at grocery and pet stores.
Feed the cat small doses of food multiple times throughout the day. This will help build up the cat's energy and prevent him from vomiting or regurgitating the food, as underweight cats are apt to do if given large amounts of food in one sitting.
Continue feeding the cat multiple times throughout the coming days, weeks and months until he reaches a normal, healthy weight.
Cats need both food and water to gain weight, therefore opt for using a moist commercial brand of cat food to add needed water to the cat's diet. Feed the cat by himself in a calm environment to ensure that he eats the required amount of food. Decrease the amount of food given to your cat once he's at a normal weight level to prevent him from becoming obese.
Underweight cats that are not attracted to food should be taken to the veterinarian immediately, as they could be suffering from a severe disease or illness.