Since smoothies are an easy vehicle for fruits, vegetables, nut and seed butter, probiotic-rich yogurt, and even whole grains like oats, they can also be a tremendous source of important nutrients besides protein and fiber. Some of these nutrients might even promote weight loss.

This can be milk, or a dairy-free alternative such as soya or almond milk, natural or flavoured yogurt, fruit juice, or for a tropical flavoured smoothie, low-fat coconut milk or coconut water. It's important to add the liquid to your blender before adding the fruit, as this will prevent the blade from getting damaged.

Once you find the right balance and taste, that smoothie can be a good thing. "It's really fine to have a smoothie every day. It can be a convenient meal replacement as long as you're making sure that it really is replacing the meal. Not too few calories, but not too many calories," says Fye.