Editors' pick: Originally published July 21.

A new study in the Annals of Internal Medicine will shake up what you believe you know about healthy eating, and that's because it says, go ahead, chow down on lots of fats and wash it down with red wine.

The study's author, Dr. Hanna Bloomfield, associate chief of staff for research for the Minneapolis VA Health Care System and a professor at the University of Minnesota, is now suggesting that the giant Department of Veterans Affairs considers recommending exactly such a diet to its 9 million patients.

Surprised? Don't be. That's because this high fat thinking has been percolating in the medical literature for some time. In fact, what Bloomfield and her co-authors did was not original research, but a literature review where they crunched data about the Mediterranean diet in 56 prior studies.

They are talking fats, but they are not talking about gorging on pastrami and fries.

Key to the Mediterranean diet is a hearty endorsement of eating what it sees as good fats - lots of olive oil, fatty fish such as sardines and tuna and high fat nuts and seeds. Lots of veggies and fruits also are on the table. Theres not much, if any, red meat. No butter. Whole grains are allowed, but not white bread. Proponents argue that following this regimen promotes better health.

Bloomfield's literature review says just maybe it does. She found that there is no evidence that the Mediterranean diet improves longevity - that is, we don't live longer, because we eat it. But those who eat a Mediterranean diet appear to have fewer heart issues, and there also may be benefits related to breast cancer and Type 2 diabetes.

The study says that "a Mediterranean diet with no restriction on fat intake" may promote better health.

Of course, for several generations, Americans had been told by nutritional authorities to carefully monitor fat consumption, because, said the experts, fat promotes obesity.

But that anti-fat bias has been under attack for some years. "Don't eat fat was from the 1980s and early '90s. That's ancient thinking," said Eric Feigl-Ding, a nutritionist at the Harvard Chan School of Public Health. He added: "There are good fats."

But there remains a hesitation to embrace fat. The American Heart Association, for instance, said that healthy Americans should: "[Eat] between 25 and 35% of your total daily calories as fats from foods like fish, nuts, and vegetable oils."

That sounds high? Maybe not high enough. In an interview with the New York Daily News, Bloomfield said we could eat up to 40% of our calories in fats.

When asked how much fat we can eat by the Washington Post, she did not give a specific number but said: "A lot."

The best guess, incidentally, is that in the typical American diet we eat 35 to 40% of our calories in fats - exactly on Bloomfield's mark.

So why are so many of us obese - more than one third of U.S. adults are, according to the Centers for Disease Control - and heart disease remains the single biggest killer? We are eating the wrong fats.

Know that there are bad fats. Feigl-Ding pointed to trans fat (mainly found in hydrogenated oils).

Saturated fats - mainly found in animal products - are also frowned on by most nutritionists.

"it's not so much the amount of fat in people's diets as it is the quality of the fat," said Elana Natker, a nutritionist in Virginia. "It's well-established that unsaturated fats are more heart-healthy - of those, the monounsaturated fats and omega-3 polyunsaturated fats in particular."

Olive oil is a poster child for a monounsaturated fat. So are avocados and many nuts.

As for omega-3 polyunsaturated fats, that's found in some (generally oily) fish.

Even though many of the staples in a Mediterranean diet seem high calorie - like olive oil, nuts and fatty fish - we may eat that diet and not gain fat. In fact, said Natker, "obesity would go down if we ate Mediterranean."

But don't think this is a green light to chug olive oil and eat Nova platters by the dozens. Long Island nutritionist Robyn Lanci said: "A fat is still a fat. A high fat diet is not ideal, for weight loss or health."

Lanci has a point: eat a lot of fat and very probably you will be fat. Eat a lot of anything, and you will be fat.

"It's all about portion size," Lanci added. Pay attention to how much you eat and what you eat, suggested Lanci, and very probably you will do O.K. And if in doubt, she suggested this: "Eat your dinner on a salad plate. That's portion control." 

This article is commentary by an independent contributor. At the time of publication, the author held TK positions in the stocks mentioned.