Healthy BBQ Chicken without BBQ Sauce

I found this recipes online quite some time ago and my family adores it.

2 lbs skinless chicken breast (bonesless OR bone-in)
3 cups ketchup (Hunts makes a great 100% natural, no salt added, NO high fructose corn syrup)
1-20 oz bottle of diet 7 up
1/2 cup diced onions
2 tsp minced garlic
Salt & Pepper to taste

Combine all ingrediants in a pot and let simmer on medium for 30 minutes.
Simple as that!

You can jazz it up with hot sauce or chili powder to add some heat to it.