Both juices and smoothies are very efficient ways of packing nutrients into your diet. I recommend having either a juice or a smoothie every single day! You see, it would be pretty unlikely to eat 1 apple, 2 celery stalks, a handful of kale, a handful of spinach and half a lemon with some ginger in 1 sitting. Therefore, it is more effective to combine them together into liquid form.
The main difference between juices and smoothies is fiber. When you make a juice, the fiber from the fruit and vegetables is removed. When you make a smoothie, the fiber remains. This is not to say that smoothies are better than juices, they are just different in how they affect your blood sugar levels. Fiber helps to slow down the absorption of the sugar into your blood stream.
When you are juicing you want to make sure that you are using lots of green vegetables instead of just carrots and beets. As you may know, some vegetables have higher glycemic indexes than others. When food has a high glycemic index, it spikes your blood sugar levels up higher than a food that has a low glycemic index.
When you are making smoothies, it is advisable to incorporate 50% fruit and 50% leafy greens rather than making a smoothie from all fruit. Spinach is the best leafy green to add to your smoothie if you are looking for a very mild taste. Since you are already getting some sweetness from the fruit, it would be best to use water or milk as the liquid part of your smoothie instead of fruit juice.
Regardless of whether you are consuming a smoothie or a juice, it is important to also have a protein and a fat at the same time. It is easier to incorporate protein and fat into a smoothie by using nut butter, flax seeds and some protein powder. It is not much harder to incorporate a protein and fat at the same time while consuming a smoothie. The importance of adding carbohydrates and fat to your daily smoothie or juice routine is to keep your blood sugar levels balanced. You will remain full for longer when you consume some protein with your juice or smoothie.
My suggestion is to keep some variety in your diet. So instead of just drinking smoothies or just drinking juices, I suggest that you alternate between the two. It is also optimal to rotate through different recipes so that you can incorporate a variety of different vegetables.