I often weigh my food to track it. If I select a food like “Spinach-cooked from fresh” should I weigh it before or after cooking?
I like to weigh food before cooking, because water content varies with different cooking methods. The good news is most foods seem to have similar nutrients before and after cooking when you compare the USDA raw and cooked versions. The inconvenient news is food in the NCCDB tends to be the cooked version, so you'll either need to weigh the cooked version, or figure out how to convert the raw weight to cook weight for logging. I use this trick:
How do you change the calorie count of the cooked version to the raw version?
On the web application, click on the calories number of the food and replace with the updated number. I don't think we can do the same thing on the phone apps.