That is a lot of fat, especially if he is a pup that doesn't usually get a lot of table food or fats. Eating a high fat meal can predispose to pancreatitis (inflammation of his pancreas causing increased enzyme production, usually related to a high fat meal).
Since he just ate this, it's worth trying to get him to vomit it back up and avoid problems.
You can give him 1 tablespoon of 3% hydrogen peroxide per 10 pounds of body weight soaked up with bread chunks or a small amount of food or ice cream (no more than 3 tablespoons per dose even though he weighs more than 40 pounds).
Then take him outside and run him around to get the peroxide bubbling so he vomits.
If no vomiting in 10 minutes repeat the peroxide dose once.
If he vomits and seems to clear his stomach and brings the grease back up then you can avoid problems.
Once he clears his stomach to try and settle his stomach today you can give either:
1) Pepcid-ac (famotidine) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 12 hours. (one and one half of the 10mg tablets for him)
2) Prilosec (omeprazole) at a dose of one 20mg tablet per 40 to 80 pounds of body weight every 24 hours.
Either of these will reduce stomach acid and should help settle his stomach. They are quite safe and can be used for a few days.
Then feed a homemade diet of 1/3 boiled, lean hamburger or boiled, white, skinless chicken, all fats and juices drained off the meat, and 2/3 white rice. Add 1-2 tablespoons of canned pumpkin, (not pie filling, just pumpkin), to each meal for fiber.
If you don't have peroxide you can choose to get him to a veterinary clinic to induce vomiting or take a watch and see approach.
If he doesn't vomit the grease back up even with the peroxide or you choose not to take him to a clinic still use the acid reducers and bland diet with pumpkin to try and counteract any possible stomach upset. Expect to see some loose stools with all of that fat.
If you choose not to induce vomiting with peroxide or he doesn't vomit the grease and in the next few days he starts vomiting, has a tense painful belly or refuses to eat or runs a fever (more than 103F rectally) then that can signify pancreatitis and he should be seen by a veterinarian immediately.
Please let me know if you have any further questions.