Your gut bacteria loves fiber. Fiber literally feeds them by helping them perform better for you and also keeps you regular. Fiber can help prevent constipation by adding bulk to stool and helping speed its passage through the digestive tract.
One fruit that is a nutritional powerhouse and loaded with healthy fats is the avocado. It shines in its fiber content. The fat is mostly monounsaturated, which helps lower levels of LDL (bad cholesterol) A whole avocado provides roughly 6 grams of fiber. Avocados are a good source of vitamins E, C and K, folate and potassium.
In terms of calories - a regular sized avocado range from 200 to 300 calories. Try and stay within your daily calorie intake and never overdo it. Refer to "Heal Your Gut. Tip #2" for mindful eating habits.