There are a few things that could happen,

She could lay a small viable clutch.
She could lay slugs.
She could become egg bound.


She also could take longer than a larger female to recover and not breed for you next year. (which is most likely if she lays). If this happens you are trading a small clutch this year for a larger clutch next year.

Or she may not lay any eggs at all. I have a 2005 female that is about 1300g (she only eats every other time to every 3rd time she is offered). I have bred for the past 2 years and she has not laid eggs even though she has locked up numerous times.

You have to weigh the risk to your female (there is always risk even with big healthy girls) vs the benefit of the outcome.

Good Luck!