The freshness of your bananas might affect how sweet your licuado is. The sweetness and intensity of the banana flavor increase with the ripeness of the bananas. If you would rather not add any more sweetness, you can change the amount of agave syrup to suit your tastes or leave it out entirely.
To make this meal more satisfying, I used full milk, but you could also use nonfat milk or your preferred dairy-free milk substitute. Almond, cashew, or oat milk are excellent choices.