You'll find that it does vary by the dog. I feel Alli a massive amount (I think about two cups a day!) of a high energy food and she's lean as they come. Our much larger dog eats the same of a lower cal food and still has to watch her weight.
Douglas eats .45 of a cup TOTAL per day, so less than 1/4 cup a serving. Very small amount and people not used to it tend to feel very bad for him like he is being fed too little, however he's a food hound and would very rapidly become fat without my monitoring his food intake carefully. It happened once where family watched him and overfed him and boy was he getting chubby fast.
Make sure you count treats as food intake too- drop the meals if they get a ton of treats because they add up fast and can make a very fat dog!!