You can't really compare these and why does it matter, both are bad, so why shouldn't everyone try to reduce both as much as possible.

Food waste is responsible for 10% of all GHG emissions. Plastic is made from petrochemicals, and as people use less fossil fuels in their cars this has been diverted into making more plastic, such as fast fashion clothing as well as single use plastics.

Also, there are trade-offs. So, some food has a longer shelf life when wrapped in plastic with an inert gas, so less plastic could increase good waste.

The best thing to do is only buy the food you need and can plan to use all of it, store it in a way which makes it last, utilize your freezer to avoid food waste. Try to choose more sustainable plastic free options where possible, but if you already own plastic items then keep using them as that's much more sustainable than replacing them. Try to recycle where possible (but many plastics cannot be recycled). If everyone makes steps to reduce their waste then it will make a positive impact and be better than just focusing on one issue.