You weigh the meat after cooking if talking about solid meets like chicken beef or pork because weight is lost due to moisture content changing so I always weigh once cooking is complete. Now that you brought up the point even weighing ground meat after browning makes sense for it definitely looses water content during cooking. I never thought about it when making something like Chili but will definitely weigh it next time to see the difference. Just checked with a coach, apparently there are weight measurements listed for ground meets cooked or raw. She did mention that 4 ounces ground beef raw becomes 3 ounces cooked, My thought use raw weight if given when cooking with ground meats if available but cooked weight for individual portioned meets ie beef or pork.