Software Validation Help

I know that when requesting FDA approval for a new drug or device, one needs to go through several phases. is there an equivalent for approving new software (one that deals with weight mangement, and does by no means involve automating a new device or administering drugs)?
Kindly advise

If the software falls within the quality arena, which it sounds like it does then you must validate the software in accordance to your in house Software lifecycle, (SLC). Your SLC process should align to Gamp4 or you could use Gamp4. This will identify the key phases you need information about. But in summary.
Identify business requirements,
Formal identify and apply a software unique number
Identify detailed software requirements, (functionality).
Using the above execute a supplier assessment to sacle your SLC activities.
Execute Risk assessment to create a risk based approach.
(Focus project efforts where required, level of criticallity).
Code or configure software
Execute a code or confif review
Document code design or configuration
Test design and SOPs
Document testing report to state ready for formal validation.
Document your validation plan
Execute IQ, OQ, PQ (IOQ maybe vendor driven)
Use formal change management to manage errors / execptions.
Document validation summary report as fit for use / production use.
Place configuration in software config library for disaster recovery, if applicable.
Install software.
Document and follow maintenance SOP.

If the above software comes installed to equipment then the above should be execute but as a system validation, ie. Joined IQ, OQ, PQ validation.
If you have to do some in house configuration, use the Gamp4 risk based approach to focus your project effort.

Not knowing exactly what equipment - software you have, I hope this helps.
Your supplier evaluation may result in you having to do a lot less pending the results.
If its COTS from a quality vendor then it may just require a vendor IOQ & SOP.
Without more detail its hard to say.

If you’re looking for a cost-effective, streamline approach to validating this software according to its intended use, then feel free to give us a shout.