Before I begin, I am no professional. Everything I write is pure speculation and is probably wrong. I encourage people to point out whatever that does not seem right and discuss.
Background: Yeet hay or "hot air" is used in Chinese medicine to explain certain "illnesses". They will say it's caused by eating certain food that are full of "hot air". To counteract this, people eat "leung" or "cold" food, commonly in the form of herbal tea (leung cha) in order to balance out the hot air.
Some common symptoms of yeet hay:
acne
sore throat
bad breathe
canker sores
Once again, I am not a dietitian and this is my speculation. My theory is Yeet hay is a deficiency of vitamin C.
Eating Yeet hay food somehow decreases your vitamin C stores in your body. If you look at the symptoms, they are explainable with lack of vitamins:
Acne - Vitamin C is an antioxidant and is needed for skin regeneration (
http://www.associatedcontent.com/art...pg2.html?cat=5)
Sore throat - Common cold, vitamin C remedies, etc
Bad breath - Gingivitis, scurvy, and other gum disease linked with vitamin deficiency (
http://altmedicine.about.com/od/heal...um_disease.htm)
canker sores - No real link between Vit C and canker sore but B12 and folic acid deficiency is confirmed. Perhaps the only link with Vit C and canker sore is that Vit C boosts immune system (
http://www.teatreewonders.com/vitami...old-sores.html)