One thing that holds people back when traveling is a fear of food poisoning. Anthony Bourdain offers the best advice on this subject: Find the Line.
If a vendor or restaurant has a long line, you can reasonably assume the food is turning over quickly so it is fresh. A local business won't have a long line if it is regularly poisoning people.
Once you find the right restaurant, order what everyone else seems to be ordering. Don't order fish at a place known for beef.
Many people label a reaction to the local water "food poisoning".
If you are concerned about getting sick from the water, stick to cooked foods and bottled beverages. You can also build up your stomach by taking probiotics or eating yogurt with live cultures for at least 2 weeks before departure.