Just like the glass of juice, a cup of coffee is not a meal! Not only do you need more nutrients to fuel your body, a strong cup of coffee without food can be very hard on the stomach.
So packaged smoothies aren’t automatically out of the question. But some are often mostly carbohydrate – fruit, maybe some veggies, maybe some sweetener. Pay attention to what is in the pre-made smoothie so you can decide how best to incorporate it into your meals!
For example, if the smoothie has very little protein and fat, use the smoothie as your carbohydrate for the meal for plenty of energy for your brain and deliciousness for your taste receptors. But try adding some protein and/or fat to make it into a filling meal. Like maybe a boiled egg and some turkey bacon.
If the smoothie has a large amount of carbohydrate and you have blood sugar concerns, maybe consider reducing how much you drink of it, or even making your own smoothie, and incorporate yogurt, protein powder, cottage cheese, or hemp hearts to add some protein.