All really good dog food. FWIW, Nutrisource Performance is 488 kcal per cup, so there are a few that fall into the same range of kcal per cup. A lot don't and like you, I think more calories per cup are better. I fed Inukshuk 30/25 for a while but it didn't work for my Vizsla. Wasn't the food...it's him but I play the cards he gives me.
A lot of people swear by glycocharge for recovery on long, multi day trips but you're supposed to mix and serve within 20 minutes or so of putting them away for the day. Works better in plastic bowls vs metal too....I've been told. Unfortunately, my dogs don't always want cold water in cold temps, as soon as they got back to the truck, didn't like the flavor and mixing it wasn't always my first priority. It didn't work for me or my dogs. I wanted to see if the Alpha would/could provide similar benefits and replace the glycocharge in a different delivery form and without the time constraints. I don't normally give my dogs supplements but long, out of state hunts can be hard on dogs so I am going to see if I notice any difference or benefit in recovery during and after several days of hunting. I'll be the first to admit if I don't see any benefit.
I guess my point was that Extreme Dog Fuel, Pro Plan, and throw in Nutrisource if you want are what I would consider mid-range foods. They are all about the same. Inukshuk and Dr. Tims are top tier. Working dogs need a food high in Fat and Protein. The problem with supplements are that you have no idea what you are giving to your dog. These things are monitored and tested really. Like I said, very few studies out there but here is an interesting take.
https://www.sciencedirect.com/science/article/pii/S0022316623022927
Minerals and vitamins
Meat is deficient in trace minerals and vitamins. Many dog owners feed
vitamin supplements but take no account of vitamins and minerals already present in the food; thus toxicity is possible. Most commercial
pet foods contain sufficient vitamins and minerals for sedentary dogs, but this balance of vitamins and minerals may have to be altered for exercising dogs. It is likely that endurance racing dogs, which consume large amounts of food, may require less vitamins and minerals per joule than greyhounds, which consume little more food, vitamins and minerals than sedentary dogs.
Gannon (1980) has suggested that exertional rhabdomyolysis may occur in greyhounds that are raced too frequently because the recurrent acidosis that follows each race increases potassium loss in the urine and leads to intracellular potassium deficiency. This seems unlikely, however, because
Knochel et al. (1985) found that training increased intracellular potassium, skeletal sarcolemmal sodium

otassium
ATPase activity and the muscle membrane potential, but reduced plasma potassium concentrations and reduced the increase in plasma potassium concentration after exercise.
Some vitamins, particularly antioxidant vitamins, may have a pharmacologic action during exercise. The antioxidant
vitamins E and C may inhibit
free radical production in
skeletal muscle during rigorous exercise (
Jenkins 1988). Very large doses of vitamin E are often given to racing dogs but an appropriate dose is unknown. Vitamin C is not an essential nutrient in sedentary dogs and is present in fresh meat but may also be conditionally essential in racing sled dogs. Signs of scurvy were observed in sled dogs fed stored frozen meat for long periods (
Butson 1973). These signs were prevented by feeding fresh meat. A decrease in plasma ascorbate in racing sled dogs was also prevented by administering 4 mg/(kJ ⋅ d) by
mouth (
Kronfeld and Donoghue 1988). The oxidation of fat when meat is stored may also increase this requirement for antioxidants.