A low-FODMAP diet is indicated when an individual with irritable bowel syndrome (IBS) symptoms, or other ongoing digestive complaints, has not found relief through stress management and first line dietary changes i.e. restricting alcohol, caffeine, processed, deep fried, or spicy foods, and other IBS triggers.
FODMAP refers to a group of fermentable carbs that can be troublesome for sensitive individuals. The 5 possible “culprits” are excess fructose, fructans, polyols, lactose, and galactans. Individuals are generally sensitive to 1 or 2 of these.
However, high-FODMAP foods provide prebiotics and other vital nutrients, and they are important for gut health.  The desirable outcome is to allow time for symptoms to abate then gradually reintroduce these foods one at a time and identify specific food sensitivities.
 Stage 1
 
Restrict all high-FODMAP foods until gut symptoms have been eliminated.  This could take 3-8 weeks.
 Stage 2
 
Gradually reintroduce high-FODMAP foods to identify which ones you can tolerate and how much (your threshold).  
 Stage 3
 
Establish a modified low-FODMAP diet that is personalized to your food tolerances.  In this way you can include as many of the nutritious high-FODMAP foods as possible to improve gut health and add variety to your diet.
A detailed chart of high-FODMAP foods is attached for your convenience: