Ziwipeak is a calorie dense food. I feed each about 1/4 at each meal (I am feeding double because they are puppies still). There are plenty of people here who feed 1/8-1/4 cup of kibble as well.
Ziwipeak has no grains, no vegetables, no fruit, no fillers. It is meat. Therefore, they do not need as much to feel as full and to get the calories and nutrients they need.
The small bag lasts us 2 weeks, keeping in mind we feed double. Once we cut back a bit, I would expect a bag to last them 3 or so weeks. They are 3 3/4 lbs. at the moment.