• by Thom Forbes  @tforbes, September 2, 2014

A new study adds some lean muscle mass to the theory that a low-carb diet is more effective that a low-fat diet for losing weight and reducing the risk of heart disease. 

“Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial,” which is published today in the Annals of Internal Medicine and funded by the National Institutes of Health, notably “included a racially diverse group of 150 men and women — a rarity in clinical nutrition studies — who were assigned to follow diets for one year that limited either the amount of carbs or fat that they could eat, but not overall calories,” reports Anahad O’Connor in the New York Times.

“Though both groups exercised at about the same rates and consumed similar amounts of calories, the low-carb group lost almost 8 pounds more over the course of the year — and more fat as a proportion of their weight,” writesTime’s Mandy Oaklander. “Both groups dropped their levels of LDL cholesterol, but the low-carb dieters had higher increases of the so-called ‘good’ HDL cholesterol.”

There are two caveats, notes the Washington Post’s Linda Searing: “The study measured risk factors for cardiovascular disease but did not last long enough to measure actual development of the disease. Dietary data came from the participants’ responses on questionnaires.”

And as positive as the results may seem to, say, the dairy and beef industry, caution is advised in trumpeting the results if the researchers’ own cautious words are heeded.

“This study shows if you are overweight and have cardiovascular disease risk factors and haven't had success on other diets, certainly a low-carbohydrate diet is worth a try,” the lead author, Dr. Lydia Bazzano of Tulane University in New Orleans, tells Reuters’ Andrew M. Seaman.

The study, however, continues the trend of good news for foods that contain fat (other than the trans fats that have, for the most part, been removed from processed foods in recent years and face further FDA restrictions).

Photos of a slimmed-down LeBron James caused a bit of a stir last month when they were posted on his Instagram account and observers credited a no-carb diet for a 10-to-12-pound loss, the New York Daily News’ Bernie Augustin reported. 

By the time Men’s Journalgot a hold of the story a couple of weeks later, the born-again Cleveland Cavalier was said to have lost some 15 pounds the same way the Los Angeles Lakers had two years ago under the guidance of Dr. Cate Shanahan, who advocates that people “aim to get 50% of your calories from healthy fats, 30% from protein, and 20% from healthy carbohydrates, ideally whole fruits and vegetables.”

That’s clearly not the kind of story that bakers, pasta makers and cereal purveyors like to read. The USDA’s Dietary Guidelines issued in 2005, in contrast, recommended that carbohydrates supply 45% to 65% percent of daily calories. But it’s clearly good news for butchers, as well as for investment bankers. 

As “health-conscious consumers are replacing carbohydrates like bread and cereal with more animal protein, including meat, yogurt and eggs” and “farmers around the world expand their production of meat,” as the Wall Street Journal’sJacob Bunge reports, there has been a “frenzy of multibillion-dollar” deals such as Tyson FoodsInc.'s planned $7.7 billion acquisition of Hillshire Brands,” reports the WSJ’s Tom Gara. “It’s a protein-crazed world we’re living in,” he concludes.

But the new NIH study’s “findings are unlikely to be the final salvo in what has been a long and often contentious debate about what foods are best to eat for weight loss and overall health,” points out the Times’ O’Connor.

Indeed, in Wired this month, Sam Apple reports on the “Energy Balance Consortium Study,” which is “designed to answer a question you'd think we'd have answered long ago: Do we get fat because we overeat or because of the types of food we eat?”

Backed by the Nutrition Science Initiative, a nonprofit launched in 2012 by science journalist Gary Taubes and former physician and medical researcher Peter Attia and supported by $40 million in grants from the Laura and John Arnold Foundation, the study has attracted research scientists who don’t agree with Taubes’ hypothesis that “carbohydrates, not fat, were more likely to be the cause of the obesity epidemic” but hew instead to the more popular “calories in/calories out” model to explain weight gain and loss. That’s because the researchers have been assured that there’s enough money available to get the science right, Apple says.

Indeed, Taubes himself “is advancing a study that may refute a theory he's built his career on,” foundation president Denis Calabrese tells Apple. “It may blow his theory right out of the water.”

Or, it may clear a lot of space in the middle aisles.