Hi,
When you say limited walking, how limited? Also are you still driving, walking around the house, etc? These are all things that are using that leg and potentially preventing the healing process.
Healing is a very individual thing, people heal at different rates and this can be influenced by environment, diet, medication and a range of other things. Calcium is an important part however there's also a whole range of other vitamins and minerals which are important in healing.
If you have been told that you should be non weight bearing, then that means literally, NO WEIGHT through that foot. Not even standing still and putting your foot on the floor. Having been given the boot I assume you are partially weight bearing however it is often quite easy to put more than the allowed weight through the foot.
If you are concerned about the rate of healing, speak with your consultant and express your concerns. It may just be that it's taking a bit longer than usual but they should be able to talk you through the process.
I hope this is of some help, please feel free to contact me if you need any further information.
Ruth Cheesley BSc(Hons) MSc MCSP
Chartered Physiotherapist