Which is one good for health?
Obviously, no doubt stainless steel boxes are good for health as they don’t react with food. But, the liquid form of gravies would leak outside in these boxes.
Tupper ware are made up of plastics and at certain times they start reacting with food directly. As we all knew that plastic is 100% bad for our health. People prefer Tupper wares as they are easy to carry with no leakage and encouraged to carry food with hot. Continuous usage of these containers leads to serious ailments that we are least bothered to analyze.
Glasswares are neither good nor bad because glass ware lid is made of Tupperware. Though glass would not react with food directly, but the lid would.
Conclusion : Stainless steel boxes are recommended, though they are little difficult to carry and handle.