I use Zupreem as an addition to everything else I give my M2. I always have a 3rd bowl in the cage of pellets and a mixture of seed and nuts for Maluka to munch on at it leisure. However, I always have a variety of fruit, veggies, and so forth. I agree they need a variety. If your Too doesn't eat it...keep offering it. You will never know when he will come around and eat it.
PS. Sometimes if you eat a piece of fruit in front of him and act like you are just thourghly enjoying it....it gives them the drive to want to try it. Course don't give them what you have bitten....have an extra piece in your hand.