A Mediterranean diet with unlimited fat intake may provide some protection versus breast cancer, diabetes and heart problems, according to a new review. However, it doesn’t reduce deaths.
The analysis of previous studies was published Monday in the Annals of Internal Medicine. While not definitively, the study’s results are consistent with another study published in June in The Lancet Diabetes & Endocrinology.
Mediterranean diets consist mainly of legumes, grains and cereals, along with fish, moderate consumption of red wine and fish, and low consumption of red meat.
These diets are also defined by a high ratio of monounsaturated fats such as olive oil compared to saturated fats such as butter. Total fats, mainly unsaturated, are supposed to account for 30 to 40 percent of calories. But the analysis found there was no need to limit consumption of these fats.
The review was led by Dr. Hanna Bloomfield at the Minneapolis VA Health Care System’s Center for Chronic Disease Outcomes Research. It cautioned that the evidence contained flaws, such as a small number of the randomized controlled trials that met the criteria, risk of bias and low strength of information.
“Limited evidence suggests that a Mediterranean diet with no restriction on fat intake may reduce the incidence of cardiovascular events, breast cancer, and type 2 diabetes mellitus but may not affect all-cause mortality,” the article stated. It can be found at http://bit.ly/meddietfat.
June’s Lancet study, which was not included in the analysis, found that people on a Mediterranean diet rich in vegetable fats from olive oil or nuts manage weight as well as those on a low-fat diet. Moreover, those on the modified Mediterranean diet don’t have to count their calories, according to the study.
Traditional approaches to dieting put calorie-counting first, an approach which indeed can reduce weight when rigorously adhered to. However, keeping the weight off is far more difficult, because calorie-restriction diets can leave people perpetually hungry.
Mediterranean diets have attracted attention because they offer health benefits without the drastic privations some diets impose. These benefits are not related to weight loss, Bloomfield said, because the Mediterranean diets examined aren’t designed for weight reduction. Instead, they are designed to improve health, especially heart health.
If people want to lose weight on these diets, they should look first to cut sugar and processed grains, while preserving intake of the fats like olive oil, Bloomfield said.
Fats not created equal
The perceived role of fats has changed over the decades. It was once assumed that consuming fats make you fat, so diets stressed reducing fat intake. This carried over into government and medical society dietary guidelines, which used to tell people they need to limit overall fat intake for health.
But lumping all fats together is not accurate, said Nick Yphantides, chief medical offer for the County of San Diego. Fats can harm health, or actually contribute to improving health.
“All fats are not created equal,” Yphantides said, using one of his favorite catch phrases. Certain kinds of fats, such as the monounsaturated fats found in olive oil and nuts, are healthy. Omega-3 fatty acids, found in fish, benefit the heart. Trans-fats, created artificially, are harmful and should be avoided.
Apart from his medical training, Yphantides knows quite a lot about obesity and Mediterranean diets. He is of Mediterranean origin, having been born in Greece. And Yphantides was once morbidly obese, weighing close to 500 pounds. He’s lost the excess weight.
As described in his book, “My Big Fat Greet Diet,” Yphantides took a rather unorthodox approach to losing weight: He drank protein shakes and exercised on the road while going to baseball games.
Yphantides of course was not the typical dieter; he decided that his extreme obesity required a drastic answer. For those with more everyday weight problems, a Mediterranean diet offers a lot of advantages.
Mediterranean diets offer foods that are minimally processed from a variety of sources, resulting in a sound diet, Yphantides said. This fits one criterion of the county’s 3-4-50 program, he said.
That program says three unhealthy behaviors contribute to four diseases that cause more than 50 percent of deaths in San Diego County. The behaviors are lack of physicial activity, poor diet and tobacco use. The diseases are cancer, heart disease and stroke, and lung disease.
The 3-4-50 program is intended to work on all of those factors, and a Mediterranean diet can help achieve reducing these deaths, Yphantides said.
One part of the Mediterranean diet’s attitude toward fats is that they are consumed at the same time as other foods that together make a good combination.
“You’re eating numerous fruits, you’re eating a lot of vegetables, you’re eating a lot of whole grains, you’re consuming moderate dairy, and there is some meat,” mainly fish, he said. “I grew up in Greece, and in Greece we eat a lot of fish.”
These other foods play an important part in getting the benefit from consuming monounsaturated fats, Yphantides said. They replace other, less healthy fats, and are not consumed in addition to them.
“If someone says, olive oil is good for my health, I’ll just add olive oil to my bacon, that’s not what we’re talking about,” he said.
Another medical professional, Ruth E. Patterson of UC San Diego, said by email that the review, “appears to have been conducted in a careful and thorough manner.” Patterson leads the cancer prevention program at Moores Cancer Center.
“Randomized trials provide gold standard evidence about diet and health,” Patterson wrote about the review’s limitations. “However, there are few trials testing this dietary pattern in relation to cancer or any health outcomes besides cardiovascular disease.”
Dieters may find it difficult to follow Mediterranean diets, since the definitions vary, Patterson said.
“For clinical trials, the authors defined a Mediterranean diet as no restriction of fat intake and any TWO of the following SEVEN diet components: high monounsaturated-to-saturated fat ratio, high fruit and vegetable intake, high consumption of legumes, high grain and cereal intake, moderate red wine consumption, moderate consumption of dairy products, and low consumption of meat and meat products with increased intake of fish,” Patterson said.
“Given these extremely general definitions of the diet components (e.g., “high” intake), it is difficult for a consumer to know how to adhere to this dietary pattern,” she wrote. “In addition, it’s not possible to know which of these diet components were actually, or most strongly, associated with reduced risk of disease.”
Patterson said the seven healthful diet components are good recommendations for most adults. But since the review’s definition of a Mediterranean diet failed to mention restricting avoiding excess energy from fats, or refined grains or added sugar, the diet is unlikely to cause weight loss.
In addition, the consumption of red wine for potential heart benefits needs to be balanced versus possible harm from “birth defects, liver cirrhosis, and cancers of the head and neck, digestive tract, and breast,” Patterson said.
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