Trade secrets in business plan

A normal business plan comes with a confidentiality statement and includes all the information that an investor, lender or management team member would need to know to implement the plan.

You can divulge the information in stages as you qualify potential investors further and further into the investment process. Divulge the key information only to highly qualified and interested potential investors under very tight confidentiality and, possibly, other restrictive legal agreements.

Also consider that if an idea is so volatile that you can't even write it in a business plan, then how good is the idea? If it is a great idea, very easy to copy, and depends on a lot of money that you don't have, your business plan might be too risky in the first place.