Ok, I am not providing any opinion on if this dietary change is or isn't benficial, I am just providing some of the information I have dug up after researching this for myself over the past week.
For those of you who do not know - spinach is NOT a good source of iron. Although it contains more iron then your average green leafy vegitable, it also contains high levels of oxalate. Oxalates basicly stop iron being absorbed by the body. You will get more iron from broccoli.
I have also dug up some reference material about this
for those that are interested.
I will also point out that there are many "carotene's"
. Most vegitables contain more then just the beta form.
Finally, there are a sweet ton of beneficial chemicals in spinach (and all vegitables for that matter), most being complimentary to one another in a health sense.
As with all healthy eating, everything in moderation and balanced with the intent of providing beneficial nutrition to the body, while minimising foods that are harmful.
Finally, for those that want to try this or any other diet. Phase in the change over the space of a couple of weeks. Suddenly shifting your diet drasticly overnight will generally result in a negative reaction, especially if you have IBD and are flaring.