The actress and mother of two is making her return to cinema in Dangerous Ishq.
She told DNA India: "It has not been much of an effort to [stay slim]. My children keep me on my toes and that also helps me stay in shape.
"It has got a lot to do with the fact that I have always been a fit person who advocates a healthy lifestyle. I don't believe in crash diets and nimbu paani diets that promise to knock off a few kilos in a few days.
"I prefer a systematic weight-loss programme, which is the healthy and right way to lose weight."
She went on: "I am a Punjabi and I love my food. I eat everything. I eat cupcakes, biryani, fries and everything else that my kids love, but in moderation. I take carbs and proteins and have a balanced meal.
"It is very unhealthy to only survive on salads or soup because it doesn't give you the required nutrition. Working out, along with eating right, is very essential to have a healthy body and mind."
"Kareena has put me on to yoga and honestly, I love it. It is a great form of exercise and very good for the body. I do a lot of power yoga and, after two kids, it is the best form of exercise to keep you in perfect shape."
Karisma has recently described Dangerous Ishq as the first female-centric 3D film.
The trailer for the film generated over 70,000 views on YouTube in the first week of its release.
Watch Karisma Kapoor in the trailer for Dangerous Ishq below: