If you thought that all celebrities were as slim as Keira Knightley or as fit as Madonna, well, think about Oprah Winfrey. Celebs get fat too like the rest of us. And one celebrity that put on some serious weight was Janet Jackson. She was ridiculed by the tabloids until she disclosed that she had to put on weight for a movie role that didn't pan out.

As tabloids started slamming her and predicting that her relationship with Jermaine Dupri was about to end, Janet Jackson lost almost all her weight and is now appearing on the cover of Vibe magazine wearing nothing but a necklace.

How did Janet Jackson lose weight?

According to her multiple interviews, here are the secrets:

Portion control: She ate small portions that added up to less than 1,500 calories daily. Of course, it also meant no junk food which can have as many calories in one meal as you would need in a day. If you don't or can't cook healthy food, you may also order healthy foods from a delivery service in your area, as she did. The service is not yet available in all areas, though.

Healthy lifestyle: Get some good sleep, drink plenty of water, avoid white sugar and flour, and eat regularly (no meal skipping allowed).

Exercise: Nutritionist David Allen made sure that Janet exercised six days per week.