Amy, if you don't see them eating, then they aren't eating. Since they can go for months without food, that's why they have not appeared to lose weight (yet). Eastern newts do this sometimes (come out of the water and refuse food), and if you don't change things, these could die. It nearly always happens in summer, when heat stress adds to whatever other problems they might have.
Reduce the amount of available land space. Keep the land moist. Lower the temperature. Put a frozen bottle of water in the tank every evening and, if possible, open the windows to get the room cold during the night (assuming your weather is cool now). If there are any other animals in the tank (fish, etc) remove them. Also, test the water for ammonia if you haven't. Do a "gradual" tank cleaning (remove debris and do partial water changes). Try tempting them to eat with pieces of chopped worms. If you can describe their setup, there may be other things you could also try. I hope they improve!