Not all protein powders are created equally. Your best bet is to get your info from a nutritionist either in person or online. They are the people actually trained in this kind of thing. Any good health food store will have someone on hand with the info you need too.

Also another huge factor is that smoothies can quite easily be unhealthy as people have a tendency to plug them full of dairy so they are high fat, high sugar and high calorie.

Making a healthy and tasty smoothie does not require dairy at all. This will also ensure that it doesn't become bad for you. My daughter has a smoothie everyday and it was important to me that I research what was best for her. The only dairy she has is kefir and just 2 table spoons per load which typically makes about 2 pints at least. That way she is getting "good quality" probiotics and as she doesn't have a dairy sensitivity it's no issue for her to have and save supplementation. We use Vega one protein powder which is a complete powder including greens. It is vegan, gluten free and gmo free which is what was important to us. Hemp protein powder is the one that was also highly recommend to me by a RHPN last night at a class she did as it is full of amazing amino acids and is easy to digest. It really depends what you are looking for.

If you like your smoothies creamy then add half an avocado which will have the same effect as dairy but without all the badness of it and with a healthy fat in its place. Also add your omega fatty acids to your smoothie...flax, and fish oil..there are lots to choose from so what you need to look for is the highest EPA and a low omega 6 to omega 3 ratio. Any good health food store should have someone on hand to explain this to you.

My daughters go to smoothie recipe is as follows...nothing is measured unless stated

frozen strawberries
half a banana
cacoa powder or nibs
omega oil ... amount as stated on label
coconut water
tsp local raw honey
whatever veggies she is brave enough to throw in too
scoop of protein powder

she adds the honey because a tsp of local honey daily prevents seasonal allergies and sweetens at the same time.