First, you want to rule any health issues out first when a dog makes any behavioral change but if your vet gives your pup the thumbs up, there are several ways to get him to eat without disrupting his stomach.
1. Tone Down the Treats - A finicky eater is more likely to eat if he's not comparing his dog food to a liver treat.
2. Feed Often - Try feeding smaller amounts of his regular food three or four times a day.
3. Exercise - It's good for so many things and it increases a dog's hunger. Try always exercising your pup before a meal.
4. Spay or Neuter - If you haven't already, fix your pup. Besides the many health and behavioral benefits, it can help prevent a finicky eater.
5. Make it Positive - Always make feeding time a positive experience. If your pup associates it with irritability or punishment from you, he will be less likely to want to eat.
6. Keep It Quiet - Feed your dog in a quiet area without children or other dogs mulling around.
7. Try Different Times - Some dogs eat better in the afternoon, others eat better an hour after you're home. Test it and see what time and situation work best for yours.
8. Resist Temptations - Try the other tips before giving into the urge to tempt your finicky pup to eat with people food. You'll find that a few pieces of cooked chicken will perhaps tempt him for a time but he'll soon grow bored of that, too.