Is it unethical to build an online program around a theory that you have not conquered yourself yet?

For instance, would creating a program like “how to grow from a 100K coaching business to a one-million-dollar coaching business with content marketing” be unethical if you have not yet created this outcome personally but know the strategy is a proven one?

The above example could be likened to a weight loss coach telling a client she can help her lose 100 pounds with a proven method, although the coach hasn’t personally done it herself, correct?

To be clear, I am not talking about making a big claim or guarantee like “invest $10,000 in my program and start earning a million dollars immediately.” I feel there’s a big difference between teaching a proven theory and making “guarantees”. I’d really like some outside feedback though!