Provide a simpler diet: Once the fasting is over, give them food that is milder and blander like boiled chicken that is skinless and boneless along with cooked rice. In case you are giving burger, then the fat should be drained off. Make sure that you follow this diet till the dog is fully okay before restarting the normal diet slowly.
Provide some electrolytes: You can give them some pedialyte that is not flavored or Gatorade to ensure that the electrolytes lost in the dog throwing up are replenished. You can also freeze and feed them these.
Keep checking for hydration: Try and pull the shoulder blade or the skin on the back to form a tent. If the skin goes back to normal, it means the dog is hyderated well. If not and it remains lifted then you need to get the dog to the vet for some attention and treatment.