My character is a cannibal, and he collects body parts of those he kills. I've been looking for some chart, or something that has the weight of the individual parts of the various sized creatures to give to my DM and know how to fill out my inventory. The system I am using is pathfinder.
All the races have weight ranges, in addition to age and height (Dwarf, Elf etc.). Work out how tall the body in question is, or take the average weight if you don't know the height, then divide the weight up: This Kinesiology webpage provides percentages for humans, so it might need fudging for other races, but it provides some starting numbers to work with.
This forum question also provides percentages for body parts, but highlights that they can change over time, so the percentages aren't absolute; you may want to research more statistics and aggregate them for a more average set of data.
In case the above links disappear, some average-ish percentages, Plagenhoef et al., 1983:
Segment Males Females Average Head 8.26 8.2 8.23 Whole Trunk 55.1 53.2 54.15 Thorax 20.1 17.02 18.56 Abdomen 13.06 12.24 12.65 Pelvis 13.66 15.96 14.81 Total Arm 5.7 4.97 5.335 Upper Arm 3.25 2.9 3.075 Forearm 1.87 1.57 1.72 Hand 0.65 0.5 0.575 Forearm & Hand 2.52 2.07 2.295 Total Leg 16.68 18.43 17.555 Thigh 10.5 11.75 11.125 Leg 4.75 5.35 5.05 Foot 1.43 1.33 1.38 Leg & Foot 6.18 6.68 6.43
I appreciate you might be looking for a more pathfinder-oriented chart for these statistics, but your question appears to cover quite a specific (and personally never before considered or seen) circumstance, and I think that there simply isn't that kind of consideration in any existing publication.
I'd really talk this over with your DM, in all honesty.
You can just look up the total weight in the Races section
Along with whatever other things that a character receives before taking a class is their possible height and weight, which you roll (see example here)
Just compare that to the overall percentage of meat that you harvested and you have its weight. Though I agree with Ardavion with consulting your DM; this is his/her game, and this decision falls into their territory.