In part it depends on the recipe, the type of food, and how the recipe reads. Give us a page number of the specific recipe you are working with.

In most cases the trimming called for won't make more than an ounce or 2 difference. But is some cases it can.

Some recipes will read 2 lbs of ____, trimmed.

Some will read 2 lbs. of _________.

Then the trimming is part of the instructions not the list of ingredients.

Dave

Page 55 squash pickles it says 2 pounds, summer squash, peeled seeded and cut into 1/2 cubes about 4

I weighed before had like 2 oz over, but I didn't deseed them.

yield about 4 half pints, I got 6

Here is a picture of them