When consumed foods have an overall cooling, neutral, or warming effect. This observation helped form western herbalism and medicine from greek times until about the 17th century. It remains central to TCM and ayurveda. Mostly the systems agree but exceptions occur. Both are correct with context. For example radishes are considered overall cooling in TCM but in Ayurveda they are warming because they increase the digestive fire.
Rules for Thermal Properties of Foods:
- Foods that take longer to grow, like cabbage and winter squash, are more warming than foods that grow quickly, like lettuce and summer squash.
- A food is more cooling when raw than when cooked
- Chilled food is more cooling than warm or room temp. food
- Blue, green, or purple foods are more cooling than similar foods that are red, orange or yellow. , thus a lime cools more than a lemon
- Cooking a food for more time, with more oil, less water, greater pressure or at higher temp. makes the food more warming
- Foods cooked over gas or wood heat imparts more heat than food cooked with electricity
- Tropical and subtropical foods tend to be more cooling than foods grown in temperate zones