What happens if you eat old walnuts?

Eating old walnuts can lead to digestive discomfort, as they may have gone rancid due to the high fat content, resulting in an unpleasant taste and smell. Rancid walnuts can also produce harmful compounds that might cause nausea or other gastrointestinal issues. While consuming a small amount may not lead to serious health problems, it's best to discard walnuts that have an off smell or taste. Always check for signs of spoilage before consumption.