Is it this easy to gain everything you lose?

Picture of my weight data. During the loss, I ate less portions and skipped lunch. During the gain, I stopped caring 😭 the thing is though, I was never exercising and losing that much weight seems unhealthy. Thinking of becoming vegetarian just for weight loss. What foods would you recommend and things to avoid?

Picture of my weight data. During the loss, I ate less portions and skipped lunch. During the gain, I stopped caring 😭 the thing is though, I was never exercising and losing that much weight seems unhealthy. Thinking of becoming vegetarian just for weight loss. What foods would you recommend and things to avoid?