Every day I have discussions with my clients about how much food to feed their pet. Something that often confuses people is that they are following the amount recommended on the package, but their dog or cat still wants more. "They're still hungry," the client says. And because we don't want our pets to be hungry people tend to give them more food.
Stop and think about how many times you, the pet owner, eats when you're not hungry. When you go to the movies are you really so hungry that you need that popcorn and candy? When you're sitting at home watching Netflix and munching on that bag of chips, is it really because you have missed a meal? When you've finished that meal at the restaurant are you looking at the desert menu because you feel hunger pains?
People and animals eat for two reasons. First, they feel the sensation of hunger. Second, they like the taste. I'm sure that every person reading this blog has eaten something when they weren't truly hungry but just had a craving for that particular food or snack. And I'm sure every person has continued to eat until far past the point of hunger sensations having stopped. Did you ever reach the end of a meal and have been so full that you think back and realize that you shouldn't have eaten so much? But you didn't think about that until after you were finished and your pants were too tight. I've been in every one of these situations myself, so I speak from experience.
Animals are often the same way. Yes, they eat because they are hungry. But when that hunger has passed they will also eat because they like the taste of the food. Since they are continuing to seek out food that can make the owners mistakenly think that they are actually hungry, when in fact they may feel quite full. There is also an instinct that is retained in many pets where they will gorge themselves since they don't have a good long-term memory to know that they will get fed again tomorrow.
You cannot determine how much food to give a dog or cat based on whether or not they will continue to eat it. If you try this method, you will end up with obese, unhealthy pets.
Instead, use the package directions as a starting point, and then consult with your vet on what your pet's body condition score is. A highly active pet may need more than what is on the package. Dogs and cats who are basically couch potatoes may need considerably less than that amount. When I see a pet I look at their proportions and how much body fat they have on them. If they are normal then I will let the owner know that they are feeding the right amount, even if the pet still acts "hungry". If they are overweight I'll tell them to switch to a lower calorie food and decrease the amount fed, even if they are following the package and the pet wants to eat more. Most people don't realize how many overweight or obese pets we veterinarians see who always seem "hungry". If they weren't getting enough food, they wouldn't be overweight!
Pay attention to your pet and actually measure out the amount of food you are giving. It's going to be much better for your pet's health.