Dr. Oz had some harsh words for Giuliana Rancic, when he said that despite her cancer, fast metabolism, and scoliosis, the E! News host is "too skinny." Dr. Oz gave Giuliana Rancic some advice on how she can gain back the weight lost over the years.

"She's on Tamoxifen because of the cancer and she will be on that for a while," Oz told Us Weekly at The Hollywood Reporter's "35 Most Powerful People in Media" event at the Four Seasons. "But it does cause you to lose some weight, plus she has a fast metabolism, plus she has scoliosis. All those things that make her look even thinner than she really is, but there's no question that she's too skinny."

His advice? Not to "eat burgers" but to build up core muscle.

"The advice is not to eat burgers, because then you'll just get fat," he told Us. "But the real advice - I think she's heard, and we talked about it on the show - is that she actually needs to put on some muscle mass."

Dr. Oz went into more details: "This means her workouts can't be on a treadmill," he explained. "She needs to do yoga, Pilates, weights, strength-training. She needs to build up core muscle. That muscle will give you a little bit of a buffer. When you look at people who are really skinny, they are so frail that it risks their health. So she was actually bigger when she was diagnosed and I've done her show and I've talked to her many times. She needs to get back to that and she knows it."

Rancic defended her weight on the Today show this past week, where she affirmed that she does not have an eating disorder and her small frame was the result of her cancer medication.

"I have never had an eating disorder," Rancic, 40, said. "I wanted to be very clear about that. In fact, I eat a lot. People always love to tweet: 'Eat a burger.' I eat burgers. It's not working."

According to Oz, all Rancic needs is a little bit of yoga in her life. 

One blogger found a post on Rancic's blog listing her daily diet and it was quite shocking. One paragraph is particular was Giuliana's "cheat tip." Read it below:

"... if i just MUST have pasta, I will let my husband order it and have some bites of his. Or I will order a healthy dish and ask for a half order of the pasta (no cream, ever!) on the side. I will eat half of the side of pasta and pass the rest around the table so my friends can try it to. That way you are impressing the table with your generosity and cutting lots of calories:)"