Keeping food for camping

To keep food fresh is an issue for camping.  Vegetables are easier for one or two days, but meat could be hard since you can hardly have a refrigerator outside.  Some people will bring a large ice box, but this is not often an option for someone without a car.  And it makes no sense to bring a large ice box if you're going alone.

So I bought the following for this purpose.  I boiled some soup yesterday and I couldn't finish it at once, so I put them into the bottle for later consumption.  The weather is not cold and I expect it could keep the content hot for a few hours.

BU 

After two hours or so, I could the cap was pretty warm.  I believe the cap is the weakest link.

I will try it out soon by first freezing some meat, and then keep inside, see if it could keep them until the next morning.  Consuming it at the same night is problem free, you don't even need such a bottle, but I usually have can food before buying this one.