You can have up to 2-3 servings of fruits a day where one small banana is one serving. Some people may think Bananas as fattening but they are often thinking about it as a high glycemic fruit. This means that the fruit sugars break down quickly (especially the ripened ones) and they can increase your consumption fo carbohydrates and sugars. Excess sugars can increase triglyceride especially with added sugars that are hidden in various processed foods.
You can add 1 serving of avocado to replace with your banana however remember that the avocado is high in fat therefore you don't want to switch one for the other.
Hi Gigi, I admit to being confused now. You've mentioned being allowed 2-3 servings of fruit a day, there can be up to 4 servings of frut in one Nutriblasts alone, isn't the point of Nutribullet to get as much fruit & veg into your day as possible? And from what you have said about bananas, it sounds as though you should only include them in one Nutriblast max per day, is that correct?