I weigh the dogs' food on a food scale as a scooper actually has a lot of variance. Cubby is big at 17.5" and lean in the low 30's eating 85 grams twice a day which is 2/3 cup twice. Melli is a wide girl at 16" inches and change and eats 65 grams at 1/2 cup twice. We have gone through a very big food transition. We used to eat Acana but the fat is just too high. We landed on Fromm Heartland Gold Large Breed Adult (the pieces aren't big or anything) which is fabulous with my shepherd's sensitive stomach at 24% protein and 12% fat. This is a superb beef/pork option. Just recently we have moved to Addiction Wishbone Pasture (lamb) at a lean 26% protein and 10% fat to assist in long term sheltie gallbladder health. The dogs are doing amazing on this food. There are several chicken duck that are lean foods from exceptionally responsible companies. They are Horizon Amicus Adult/Senior & Weight Management (turkey, chicken, 30% protein & 10.5% fat), Addiction Wishbone Lake (Duck/fish, 26%, 10%), Annamaet Lean Low Fat (chicken, duck, herring, 30%, 9%), Earthborn Holistics Grain-free Large Breed Dry (chicken, 26%, 13%), Earthborn Holistics Grain-free Weight Control (chicken, 25%, 7%). I am not a fish fan because our seas are so contaminated and so are farmed fish.
My recommendation is to choose a lean grain-free food, weigh the amount for consistency, make sure you reduce slowly by maybe 1 or 2 grams a week until the dog leans out, and stick it out no matter how crazy hungry the dog acts.