Bring a weight log. Bring a food diary. Bring the bag of food. Your vet will thank you. Your cat will hate you. Worth it.
I have been on both sides of the exam table. As a vet tech, I love prepared owners. As a cat owner, I forget to prepare. Last month I took Luna in and realized I had not weighed her in three weeks. The vet asked about her food. I said "wet food, about a can a day." That is not helpful.
Here is what to bring:
Weight log. Weekly weigh-ins for at least a month. Same scale, same time. Write it down. The trend matters more than any single number. I use the weight tracker tool and export a CSV before every appointment.
Food diary. What brand, what flavor, how much, how often. For at least a week. "A can a day" is useless. "85g can of Brand X chicken flavor at 7 AM, 1 PM, 7 PM" is useful. Include treats. Include table scraps. Include that piece of cheese you pretend did not happen.
The actual food bag or can. Vets want to see the label. Calorie content, ingredients, feeding guide. We compare it to what you are actually feeding. Usually the numbers do not match.
Body condition photos. From above and from the side. Monthly. These show changes the scale misses. A cat can gain muscle and lose fat at the same weight. Photos reveal that.
List of questions. Write them down. You will forget half of them when the vet walks in. I always do. Last time I forgot to ask about Luna's dental health. Remembered in the parking lot.
What not to bring:
Your cat's entire toy collection. I have seen this. It is not helpful.
A list of every supplement you read about on Facebook. We will discuss what is evidence-based. The list is short.
Guilt. Your cat's weight is not a moral failing. It is a math problem. We fix math problems.
The best appointment I ever had was with an owner who brought a spreadsheet. Three months of data. We figured out her cat's issue in 10 minutes. The worst was an owner who said "he eats fine" and shrugged. That appointment took 40 minutes and we learned nothing.
Be the spreadsheet person. Your cat deserves it.
P.S. — If your vet does not ask about diet, bring it up yourself. Nutrition is half of health. Some vets are great at it. Some are not. Advocate for your cat.