To have a cast iron stomach means to have no bad side effects or problems eating or drinking anything. Iron is a hard element and tough to break so having an ‘iron' stomach means even horrible food cannot affect the delicate stomach.
1. The participants in reality TV program just could not fathom how the Korean could so speedily eat the red chillies – he seemed to have a cast-iron stomach.
2. Durga was always ready to go on outdoor camping trips and adjust to all kinds of food as she had a cast iron stomach and never felt ill.
3. Sanjeev was the ideal person to host the food program as his cast-iron stomach enabled him to try out a variety of cuisines from different countries.