Editable table in material design

we're designing a web application in material design and we have an editable table there - something like this:

Any suggestion on how to indicate the editable fields, if not all columns are editable? Let's say that in this example Protein and Comments would be editable - how should we visualize this?

I found this suggestion in Material design specification, but what if more than one column in a row is editable? The table would become cluttered with icons if we place them into each editable cell.

Would it be better to allow editing only for the whole row?

Thanks.