How to fatten up a cat:
1. Try to choose high-quality cat food that is nutritionally complete for your cat. You should buy it from a reputable merchant or store and choose a high-quality brand of cat food.
2. Feeding your cat nutritional paste 2-3 times a week can quickly and efficiently replenish nutrients and improve your cat's immunity. 
3. In addition to cat food and nutritional paste, owners should also provide their cats with a diverse diet, including fruits, vegetables, and meats, to ensure a balanced nutrition.
4. If a cat has a sensitive stomach, you can feed it some probiotics. These probiotics can help the cat digest and absorb them, which can make it easier for it to gain weight.
5. Maintain a regular feeding schedule. Cats need to eat small meals frequently to aid digestion and absorption, which will help them gain weight more easily.
