Actually, it’s better to not eat yogurt of any type for at least two weeks after starting the treatment. Benji is right about the type; if you can find what he uses, that’s best, but if not the non-sweetened organic Greek yogurt is fine.
The reason that organic yogurt is allowed after a few weeks of the treatment is because of the beneficial bacteria that it contains. The bacteria will be the most important part of your treatment in the long run. Once you’ve been on the diet for a while, you can add a probiotic supplement (in capsule form) to your regimen as well.
Just try to limit the yogurt to a small amount when you first start it, then you can raise it to a higher amount very slowly. Watch for Candida-symptom reactions as some people receive them in the beginning from the Yogurt, especially if it has 5 or more grams of sugar. If you receive a reaction, simply wait a week to ten days and try it again.
In your post you asked why certain things are allowed when they seem to contain way more sugar than things that aren’t allowed. What other items are you speaking of, may I can help you with an explanation.
Let us know if you have other questions.