Cooling Time Travel R Us is a (fictional) startup company that was going to travel back in time to combat global warming by preventing the Loch Ness Monster from being eaten by the Easter Bunny.
If I presented Cooling Time Travel R Us, the investor panel would ask me about customers. The biggest risk in the investor's mind would be about customers.
On the other hand, if I presented a company that helped people change their behavior so as to combat obesity or pre-diabetes, the investor would ask for evidence that we would be effective.
It is harder for an investor to believe in lasting behavior change than it is to believe in Time Travel, the Easter Bunny, and the Loch Ness Monster combined.
If you are claiming lasting behavior change, you will need to be very, very, very, very persuasive to convince an investor.