Here is an example of how to calculate the required amount of food for your pet:

A 50 pound dog at a healthy weight needs 2% of his body weight in food:
50 X .02 equals 1 pound of food per day, OR 8 ounces per meal, fed twice a day.
OR
A 50 pound dog that could loose a few pounds, requiring 1.5% of his body weight in food:
50 x .015 equals .75 pound of food per day, OR 6 ounces per meal, fed twice a day.

Here is another example, this time using our very own Souza, a very active 5 year old retired racing greyhound:

A 53 pound highly active dog, at a healthy weight, requires 2.5 to 2.75% of her body weight in food:
53 x .025 equals 1.32 pounds of food per day, or 10.5 ounces per meal, fed twice a day.  This is a calculation for an average day for Souza.  On a very active day, her food requirement is higher, about 11.6 ounces per meal, or 2.75%.