Hi Lisa,
There are so many on the market. It will depend on your taste and nutritional needs and alergies if you have any. Some people prefer Soy rather than Whey and the other way around. If that is all you are having for breakfast, you may want to make sure you get one that is not too low in calories and has lots of nutritients.
I know people who have done fasts or meal supplementation with shakes and you need a lot of nutritients supplied. Another thing to watch is the sugar content. Some use sweeteners so they are lower carb, but if you are watching your sweetener intake, that will affect your choice too.
Then there are some rather expensive, yet tasty shakes and some cheaper but not as tasty. But you can find reasonably priced ones that are tasty. I think they say some of the more expensive powders are because of the blend of nutrients and how many athletes have used the formulas. Basically pushed by a doctor.
Maybe just start out going to a health food store or GNC or vitamin store and make a selection. I have tried a couple of GNC versions and a few of the expensive ones and moderately priced ones. But there are so many and I had different things I was looking for in each. I don't think these are built for meal replacement. I know I have seen some in GNC that are supposed to be for meal replacement/weight loss, but I have never tried any of them.
For a very low carb option, I have used things like
Almased and GNC
Pro Performance. But they are very low in calories too, so you must make sure you get what you want out of the low carb ones. I have used the Soy GNC, but I know people that use the Whey and like it too.
I have tried some you can find in grocery stores like Designer Whey, and they are okay.
I have also tried some available from beach body, but it looks like they changed the meal replacement one. I have also tried the fast shake and it was good. I used to make fruit smoothies from vanilla whey powders that I got from Beach Body. Otherwise I usually went for Chocolate and sometimes Strawberry.
And I have tried a more expensive shake that tastes really good to me, but pricey. I can't remember off the top of my head what it is called!
Hope it helps some!
Happy weight loss!
Rocky