Paying for liquid vs actual meat is why I never buy shreded, cubed or any cat food except pate (loaf). When I pay for pate, I know I am paying for the water/juice that is contained inside the food, but the food is more solid than liquid. Also, the liquid/juice/gravy on canned cat food is often just thickened chicken byproducts broth.
I made to make a report in college on some kind of automatic system for a certain class. I picked the automatic machinery used to can cat food. Here is how it is done:
After all the meat and byproducts are mixed together and ready for canning, the machinery lines up and gives the receiving cans one last cleaning with, usually, steam. The filling machine is preprogramed with an AVERAGE weight of the empty can and as the cans ride past a depositor, the usually hot product is deposited into the cans for a specific amount of TIME determined by the actual speed of the moving line. After the can is filled, it runs over a weight sensor which is programed with a range of acceptable weight parameters. If the weight of the filled can (can weight plus food weight added together) is within parameters, the filled can goes on for either more cooking or for sealing. And that is how the food gets in the can. The weight of the food in the can is a NET weight, can plus food.
Have you tried taking the food out of the can and weighing it on a very small paper plate to determine your actual food weight? I am not someone who keeps track of how many ounces I feed my cats; with thirteen cats it is kind of dumb. But I do weigh each of my cats monthly at mostly the same time each month to make sure my cats are eating and maintaining their weight. This method is the method scientists use to help evaluate the quality of a cat's diet and whether or not a feline is getting enough to eat calorie-wise. Whether or not the cat is getting the nutrients they need, is a little harder to determine and depends on the quality of the food fed.
There is a great book, probably out of print by now, called Feline Husbandry that outlined how to maintain a scientifically adequate cat colony. It was written to help scientists maintain a healthy population of cats for scientific experimentation and addressed how to meet calorie, nutrient, emotional, social and instinctual needs of cats. I was upset it was written for scientists doing experiments on cats, but I also found it extremely informative on how to keep my cats healthy, happy and active.