Can we eat healthy without the weight loss?

Help please!
DH and I are in our 60s and we’re very thin. We always have been.
I decided a few months ago to stop eating the un-healthy foods and began eating more fresh fruits and vegetables. We stopped using any soft drinks. I never drank many anyway. I did drink a lot of milk which I stopped doing.
For a while we did the vinegar/honey drink in the morning. In about one week, we each had lost 10lbs, which would have been a good thing if we needed to lose weight.

Some other things we have done to be healthier are to take vitamins. We also drink some peroxide water and use Colloidal Silver , continue to drink lots of water and we exercise.
No matter what we do, we continue to lose weight. It seems that most of the healthy things we should do would make you lose weight.
What is out there that we could add to our diet that would allow us to gain weight and still be eating healthy?
We don’t use any of the things that are unhealthy. No table salt , no Sugar or white flour.
I still use some 100% whole grain bread and I know they say no bread at all. But can’t do without that right now anyway.

They talk a lot about cleansing and detoxifying the body. It sounds like that would be good for everyone. With our problem though, I think we’d lose more weight and can’t afford to do that. I really don’t understand about cleanses when it sounds like they are doing those for life, instead of a week or so. I don’t think we’d survive even one week on a fast and cleanse.
I’m 5’5” & weigh 116lbs. He is 6’ & weighs 178lbs.
We’re not in trouble yet, but if we continue to lose weight we will get there.
Any suggestions will help. There must be some healthy food that will allow some weight gain, or at least to stop losing weight.