INSERT can be minimally logged in some cases. See: Prerequisites for Minimal Logging in Bulk Import.
Note if you switch to
SIMPLE recovery your log chain is broken, and you'll need to start with a new full backup after switching back to the
FULL recovery model.
If you switch to
BULK_LOGGED then inserted pages are copied into the next log backup. Switching to
BULK_LOGGED does not break the chain — that's why it exists.
See Bulk Import Optimizations (Minimal Logging) by Sunil Agarwal for more details. Some quotes:
FULL recovery model, as the name implies, all operations are fully logged. Under minimal logging, the SQL Server does not log individual rows and logs only the page and extent allocations. So if each page can fit 100 rows, we are trading 100 log records for 1 log record, a significant improvement.
When the bulk import transaction commits ... the SQL Server flushes all the data pages (a subset of these pages are likely to have been flushed as part of checkpoint) to disk to guarantee the atomicity of the transaction.
When the [next] transaction log backup is taken, the SQL Server also backs up the data pages, including index pages when applicable, as part of the transaction log. This enables a database restore by restoring the database backup followed by zero or more transaction log backups. The only drawback of minimal logging is that it does not support point-in-time recovery ... If this is of concern, you can do transaction log backup before/after bulk operations.
So you typically switch back to
FULL recovery model, and take a log backup immediately after performing the minimally logged operation.