What is your goal? Supplementation is good, but a wholesale change over to powdered food is a temporary solution. Stick to the outside of the grocery store, stay away form processed foods as they are high in sugar and cause to much of a yo-yo effect.
Okay, what is quoted above is very true. I will add that due to the 28 day challenge is what truly made me look at what I ate because it is a difficult adjustment to this plan. With that difficulty included, I wanted to make sure that I stuck to it, so I changed my eating habits, and now that has stuck with me. You will feel hungry, you will pee ALOT, but you will get results even if you don't change your exercise habits. But, it you change your exercise habits, you will see a dramatic change very quickly. The first time I did the challenge, I changed my workout routine as well and was rewarded with 20 pounds down in what worked out to 33 days (I would only do the meal replacement for breakfast on the weekends dragging it out beyond the 28 days). I stayed with the workout routine that I had been on, having a meal replacement shake for breakfast, for the next three months (no weight gain) before going back to the full 28 day challenge again. This time, I didn't see the dramatic effect of weight loss mostly because of a job classification change that required a bunch of lunch meetings and quite frankly, over eating. I ended up losing about 6 pounds in the 33 days that I went through it the second time.
To the now, I no longer do the replacement shakes at all because I eat healthier and have stayed with the workout routine. What the 28 day challenge did do for me was give me the incentive to change, and I have, physically and mentally, but mostly the way I eat. Costs are going to go up as the outside aisles are fresh food and it is more expensive than opening a can, but it tastes better and is better for you.
Good luck with whatever you decide to do.