Start cold
Refrigerate the food and drink before packing. An ice pack is better at keeping cold food cold than cooling a warm lunch inside an insulated bag.
Pack the cold around the food
- Use at least one frozen cold source
- Place the most perishable food closest to it
- Keep the lunch box closed until lunch
- Use a frozen water bottle only if it will thaw enough to drink
- Discard food that has spent too long warm
Test the setup at home
Pack a normal lunch on a weekend and check it at the usual lunch time. That simple test reveals whether the insulation, ice pack, and container arrangement are doing enough.
