Should I be concerned?

I've had my 2 adult nvv newts home with me since Thanksgiving and they've both become kind of chubby. One newts gained weight immediately, the other was a good eater but went through two periods of little eating- now he's become just as hungry as his brother. I feed them live black worms every day and try to monitor how much they eat. I know newts don't need to be fed everyday, but I feel so bad because when I do feed them, they both act as if they haven't been fed in weeks! They actually attack the food! I guess I should be happy they're good eaters but I don't want them to pick up any bad habits. I've cut back on how many worms they're fed in hopes of them losing weight but if they're that hungry, is withholding food fair to them? I've read on this forum that one shouldn't worry about obesity in newts but I don't want them to become unhealthy. Is this normal? (PS- It's not bloat b/c they're very chunky in the stomach but not the rest of their bodies.)

Over feeding your newts can lead to health issues later. Just like people obese newts tend to not live as long and can actually suffer from heart ailments. In the wild they have to work real hard to find food while in captivity it is literally handed to them. They'll always act hungry because it is instinctual to eat when ever food is available because who knows when your next meal will be. I would dramatically cut down on the frequency of the feedings until they become svelte again.

I would recommend cutting back gradually. Feed them small portions for a week, then slightly larger portions every other day for a week, then the same size portions every third day for a week, then up the portions a little bit.

You don't have to worry about them. I left my cynops orientalis and my two t. grans alone for a week and a half and they hadn't even lost weight. Don't worry about them too much. I know it's hard because of how often we humans eat, but just have a little faith.

With the red-spotted newt, obesity can be quite common if fed too much. I would get a larger tank, feed them every other day, and feed them live prey. That way, they may lose weight by hunting it down because they're doing physical activity.