NYC man swears by steak-and-burger diet but nutritionist sounds alarm

Food pyramid? Who needs that? New York resident Wally Walters says you don't need much more than meat to cover your nutritional needs.

"I've cut out veggies and pasta and breads for the last two years," Walters says. "But just for the last four months, it's been strictly no sugar, no veggies."

Walters is not alone in his eating habits. The carnivore diet, which is zero-carb and high protein, is a growing trend amongst health nuts.

"I had less inflammation in my body," he says. "It was easier to get up, much more energy."

Like Walters did, many make the leap to all-meat after following the ketogenic or paleo diets. But unlike those, the carnivore diet means ditching greens, fruits, grains, and pretty much everything else.

So what does Walters eat in a day?

"Bacon, eggs with cheese in the morning, so all animal products," he says. "Then I'd have a pound of ground beef for lunch—usually burgers. And then at night, I'd either have another steak or more burgers."

While red meat like burgers or steak is the most popular meal choice, those following this diet aren't limited to that. Many also eat chicken, fish, and pork. And because they're animal products, other sources of protein and fat like dairy factor in just fine.

"For the last four months, I've felt so much better," Walters says. "I've lost 20 pounds and I don't think I'm going back."

But like any fad diet, this one is causing controversy.

Nutritionist Rachel Lustgarten has plenty of concerns. She says a diet of only protein and fat is missing out on a variety of nutrients and fiber. Lustgarten also argues the dangers of red meat and other possible long-term health effects from following this diet.

"From a weight-loss perspective, people are able to lose weight because your body uses stored fat as energy," she says. "This is not necessarily something that is going to be sustainable or healthy in the long run."