Speaking to OK, the reality star - who has dropped 20lbs - explained that she was prompted to embark on a healthy eating and exercise regime because she "wasn't feeling good".
"I did it for health reasons, I wasn't feeling good, I'm getting older. I'll be 49 next week, and the wheels are starting to fall off. You have to worry about diabetes setting in, or high blood pressure. You have to take control of your body," she said.
"I never was ashamed of being heavier, it's something I decided to do watching my husband [lose 100 lbs through lap band surgery] and starting not to feel good that I'd better take control of things."
She added that she still hopes to lose another 6lbs to reach her target weight of 115lbs, saying: "I will cap it off after 6lbs, but I will maintain. I'm certainly not going to be one of those people who are going to keep going."
Manzo - who revealed her new figure in June - also shared her weight-loss tips with the magazine, including not calorie counting, replacing soda with water and eating smaller portions.
The Real Housewives Of New Jersey continues this Monday at 10pm on Bravo.