November 26th, 2010
11:36 AM ET

Fit Friday: Fat rats, Natalie Portman's workout, misperceivers don't believe mirrors

Stuffed and content from your Thanksgiving? Here’s good news—all that turkey may not be as detrimental as you thought. Read on about high protein diets.

Every Friday, we'll give a Web shout-out to interesting, quirky or bizarre diet-and-fitness news and trends. Tell us your suggestions for interesting stories, posts or websites that caught your eye.

European study identifies most effective diet

Eating lots of protein and skimping on refined starch is the best weight maintenance diet, reports a Danish study. Researchers at the University of Copenhagen compared the results of five different weight-maintenance diets on almost 800 European families.

Their conclusion: The most effective is the low-glycemic diet - which means more lean meats, beans, low-fat dairy and less refined starch such as white bread and white rice. The glycemic index measures how carbs break down and changes our blood sugar levels. Foods that spike the blood sugar are assigned higher glycemic index numbers. For example, lima beans, peas, legumes and lentils have glycemic index below 55, while white bread, corn flakes and white rice have GI above 70.

The findings in the New England Journal of Medicine stated that the low-glycemic diet was the easiest to adhere to among the five weight-maintenance diets assigned.

But James O. Hill, director of the Center for Human Nutrition at the University of Colorado, who was not involved in the study told the Los Angeles Times, "There is not much difference among the groups right now,” about the five different diets.

Natalie Portman’s “Black Swan” workout

It may look effortless on film, but Natalie Portman worked five hours a day, six days a week to portray a ballerina in the soon-to-be-released “Black Swan.”

She trained with Mary Helen Bowers, Ballet Beautiful founder (pictured above with Portman), six months before filming and trained in the morning and evening on the set. Between takes, Portman would swim to give her joints a break, Bowers told Elle.

Why do ballerinas have such lean figures?

“Ballet targets smaller, secondary muscles that you don’t often use—instead of working your quads it works the inside and the back of your leg,” Bowers told the magazine. She said ballet requires using inner thigh muscles  and "you’re squeezing your butt to make sure you’re perfectly lifted.”

"Black Swan" arrives in theaters December 3.

Who, me? Overweight?

Maybe it’s all those trick mirrors in stores or expanding vanity sizes.

As many as one in four overweight women believes her weight is normal. A study published in Obstetrics & Gynecology surveyed 2,200 low-income women in Texas, showing that body-image distortion tends to favor large sizes.

The docs call them misperceivers.

While self-esteem matters, has it gotten to the point where overweight women don't realize their own health risks? To be fair though, about 16 percent of normal-weight women thought they were overweight.

Animals (even the sewer rats) have gotten bigger

It’s not just kitty cat or fido that have packed on the pounds over the decades. Even lab rats and street rats have become heavier, according to a  statistical analysis of more than 20,000 animals published in the Proceedings of the Royal Society B.

The mystery is that lab rats, mice and primates are fed highly controlled diet.  So why are these animals getting fatter, Discovery News asks. Rats living on the streets of Baltimore were 40 percent heavier in 2006 than in 1948. The researcher team found that all animals' weight increased over periods that spanned at least 10 years.

The findings suggest environmental factors (beyond diet and exercise) might be to blame for the obesity epidemic, according to Nature News.

Pitfalls of a French diet

A French diet that Kate Middleton's mother used to lose four pounds in four days is "unbalanced," reports the Telegraph.

The Dukan diet, named for a French nutritionist, recommends eating a high protein and low carb diet that relies on prawns and cottage cheese.  While it's helpful for rapid weight loss, the pounds return with a vengeance.  Researchers at the Institut Pasteur in Lille, France,  found that the Dukan had too much protein content, and lacked fiber and vitamin C, reports the British newspaper.

soundoff (16 Responses)
  1. jim dakis

    I think Natalie Portman is one of the greatest acteress we have. And I will see her new movie black swann!

    November 26, 2010 at 16:47 | Report abuse | Reply
  2. Lady

    I disagree about Portman, jd. She was adorable in "beautiful Girls," but never quite there in later films. The Star Wars stuff–awful!

    I am freaked out by the factoid on increasingly fatter street rats. Maybe we are just that much more wasteful with our food, so the rats are better fed? Or is it chemicals in the environment that act like hormones? I am seeing more and more young girls who are tall enough and developed enough at age 8 or 9 to be taken for 11 or 12. Could it be related?

    November 26, 2010 at 17:22 | Report abuse | Reply
    • James

      What we throw away should not effect lab rats or primates. Maybe the chemical or hormone theory is closer. Maybe the chemicals in the food they eat are causing them to increase in size.

      November 26, 2010 at 17:48 | Report abuse |
    • JLS639

      Laboratory animal strains are changing over time. It is not just body weight and it is not only in rats. I read a paper almost 15 years ago warning about how laboratory strains were changing in unexpected ways over time. Crochety papers like that are ignored until researchers suddenly find they can no longer reproduce old results and have to redo old work and ask "how could this have happened?" What is causing the changes is how breeding programs are conducted.

      The street rats are getting heavier based on the trash they are eating.

      November 28, 2010 at 08:02 | Report abuse |
  3. gala12

    Yes, that French Diet doesn't sound inspiring, too rigid and too low fat for my taste. In order not to to gain weight after such regiment I would recommend the French Diet followers to move on the Atkins diet – more fiber, more fat and more diversity + pretty good records on keeping weight off.

    November 26, 2010 at 21:05 | Report abuse | Reply
  4. Bert

    As far as fat rats go, well, rats kind of live off of people, you see more of em where people are, and in major cities. So, chances are whatever it is they're eating is stuff that was destined for the American dinner table and didn't get there. Take that one step further and ask what are YOU putting in your mouth, and where did it come from, and what kind of process did it go through before you got it? We're becoming a nation of big sick fatties...someday, we'll all look like Michael Moore...(shudder)

    November 27, 2010 at 04:04 | Report abuse | Reply
    • Alba Mendez

      agree....rats are fatter because they are eating more fatty foods from people's trash.

      November 27, 2010 at 13:47 | Report abuse |
  5. Whit

    What this article fails to mention about Portman is that she eats a strict vegan diet. I just find it ironic that the article begins by stating that high-protein diets laden with meat and low-fat dairy products are ideal, and then goes on to use Portman as the pinnacle of great fitness when she herself eats a plant-based diet.

    November 27, 2010 at 10:12 | Report abuse | Reply
    • Gala12

      It is ironic. Indeed, low-corb, adequate protein diets are ideal for majority of people,especially those, who are naturally chubby.There are some, however, who feel well on vegetarian diet. People have to limit at least something in our food consumption. We are not rats and able to think before we eat.

      November 27, 2010 at 11:50 | Report abuse |
  6. Greg

    Portman's weight in her new movie is not a realistic weight, nor is it healthy. Its very important to understand the perils of being underweight, which is as much of a problem of being overweight. For tips on proper health and nutrition, check out Holosfitness.com. The site has a wide array of health, fitness, and nutrition-related information. Holosfitness.com can help you get in shape, stay in shape, and lead a healthy lifestyle.

    November 27, 2010 at 11:44 | Report abuse | Reply
    • Gala12

      Just checked the the site, good fitness information, not perfect nutritional one – article about another athlete who follows unnatural vegan diet. Starchy vegies , beens and grains are not necessary! In order to get enough protein from that kind of food you have to consume too much carbs.

      November 27, 2010 at 11:58 | Report abuse |
    • Linda

      Interesting to note that Natalie Portman herself admitted on David Letterman's show that her movie weight was not sustainable. She has allowed herself to gain much of the weight back, feeling healthier that way.

      November 27, 2010 at 12:38 | Report abuse |
  7. JLS639

    I work in a lab where we keep mice and hamsters. Yes, the lab rats are getting faster. The Royal Society was testing an impression many researchers already had about their lab rats. Here are a few other fun facts about laboratory strains:

    Lab mouse strains are not as genetically pure as they should be based on how inbred they are. Many commonly used ones have fewer pups than they did 20 years ago and at least one is missing a brain structure that it apparently had before. Their estrus cycle lengths have changed, as well.

    Lab hamster strains are not as sensitive to changes in day length as they were even 15 years ago. The two major strains used in the United States which are descended from the same colony some 50 years or so ago have different responses to diet, different mating habits and one has females about 30% heavier at maturity than the other.

    Being kept and housed in a lab environment creates poorly understood selective pressures on a strain of animals (for example, over time males and females become more difficult to distinguish at younger ages). The lab animals today are not the lab animals of 20 years ago. This can actually create significant problems in research where current research depends on the ability to reproduce results published 10, 15, 20, 30 years ago.

    I praise studies like this and hope it makes more researchers aware of this problem and makes the vendors of these animals occasionally update the data on their strains. Body weight, food intake and other metabolic data from the vendors is often decades old. Considering how much they are charging us for these animals, they could at least keep accurate data on them.

    November 28, 2010 at 07:55 | Report abuse | Reply
  8. happyblakman

    I live in Texas and 1 in4 women are black and poor.  Are they saying all black women are fat and wellfare recipients?

    November 28, 2010 at 15:35 | Report abuse | Reply
  9. razzlea

    I think thats great that she excercised that much for the movie to depict an accurate role. But its not realistic to excercise that much , if any of us worked out that much we have super lean figures. Also i agree with the statement about the french diet of losing 4 pounds in 4 days , i mean when are people going to realize that fad diets are not realistic . Check out my health and fitness blog http://razzlea.blogspot.com/

    November 29, 2010 at 11:29 | Report abuse | Reply
  10. mike

    James O. Hill wrote a book about how if you walk enough you can eat whatever you want, so he has a vested interest in putting down studies that show a protein based diet can help people lose weight better than the tried and failed idea of "diet and exercise."

    November 29, 2010 at 15:47 | Report abuse | Reply

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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.