Some are, some aren’t. It depends on what goes into it.
Kishka (at least the ones sold in stores) are very unhealthy. Latkes are fried in a lot of oil – pretty unhealthy. There are lots of types of kugel, some of which can be very good for you, some of which can be very bad for you.
Cholent depends on how it’s made. Use a lean meat and don’t add any oil, and it can be very healthy. Beans are a good source of protein.