A new study published last week in the Journal of the American Medical Association has made a big splash in the news. For some of us, it doesn’t seem to be a big news flash, because our experiences have already confirmed to us that while eating a Mediterranean style diet, we eat enough to be satisfied, yet can wisely retain weight we have lost. Different researchers, in different ways, keep finding out the same thing – the Mediterranean style of eating (by any name) offers benefits in weight management, and substantial health benefits. This study did show that the quality of calories do matter, to both their effect on weight and to important health outcome.

This study is particularly important because it focused specifically on maintaining a weight loss of at least 10-15% of your body weight.  It was difficult and costly to do this study, because participants had to be found who could participate over a 7-month period, with a lot a time spent in a hospital to eat and to have fluid samples taken. The study used state-of-the-art methods, such as stable isotopes to measure participants’ total energy expenditure – the rate at which people burn calories. Energy expenditure declines after weight loss; which, of course, is part of the reason people have such a challenge in keeping lost weight off. Dietitians usually say, “Our metabolism slows down after weight loss.” It is a very important issue, because it contributes to weight regain. Although the U.S. Government and the Heart Association recommend a low-fat diet, (one of three types of diet studied), results showed it to cause the greatest decrease in energy expenditure of the three (it slowed metabolism the most and made it easier to gain the weight back).

The researchers found when comparing the three different diets that the participants burned about 300 more calories per day on the low-carb diet modeled on the Atkins diet, than they did during the low-fat diet. The low-carb diet (Atkins-style) actually left people with the greatest energy expenditure after losing the weight. This is important, because when people lose weight, their metabolism drops to a lower level of energy used. At first glance, this is an exciting outcome. Unfortunately, during and after the 4 weeks of low-carb meals, they also had an increase in cortisol, a stress hormone, an increase in CRP, an indicator of inflammation, which is associated with an increase risk of developing heart disease and diabetes, more insulin resistance, and higher cholesterol. These are serious problems for this eating style of weight loss.

Of course we will expect the Atkins people to put up a big fight over this study; as there are so many products and so much revenue at stake for their company’s low carb diets. They will point out that the study was small; but this type of study is very expensive and complex to administer. Finding people who would partake of such diets for many weeks, and allow themselves to undergo costly testing, cannot be done on a large scale. Large-scale studies assess much easier to-measure aspects of thousands of people, and can only assess statistical correlation, not whether some diet actually causes more or less energy expenditure, stress hormones, insulin resistance, and cholesterol, to name a few of the measures taken in this study. One of the reasons that this study is getting so much press is that it is designed to actually show cause; that is, not make guesses about what caused a population’s results to happen.

When the participants were on a low-glycemic-index diet (essentially a Mediterranean-style diet), they burned about 150 calories a day more than those on the low-fat diet. The good news about the low-glycemic diet is that the people did not have any negative impacts on cholesterol or hormones during the weeks they ate it. The participants that followed this diet ate fish, fruit, vegetables, nuts, legumes, whole grains and healthy fats like olive oil. Their cholesterol levels and other risk markers were reduced on this eating style.

David Ludwig, MD, the director of the New Balance Foundation Obesity Prevention Center Boston Children’s Hospital (sponsored by the athletic shoes – New Balance), said that “We’ve found that, contrary to nutritional dogma, all calories are not created equal. Total calories burned plummeted by 300 calories on the low carbohydrate diet compared to the low fat diet, which would equal the number of calories typically burned in an hour of moderate-intensity physical activity.”  But losing calories this way comes at a cost – increased risk for cardiovascular disease and diabetes.

In summary, although you can get your energy expenditure (metabolism) to burn an extra 300 calories per day on an Atkins style diet compared to a low-fat diet, it can increase your stress hormones and inflammation. The safest way to lose weight and keep your metabolism up is the Mediterranean style of eating. Many say it is also easier to maintain this style of eating for the long term because whole groups of foods are not eliminated. You cannot cut carbs down to 10% of your diet and eat the fruits, vegetables, and whole grains in the low-glycemic (Mediterranean) diet. When you do eat the Mediterranean style, you can eat enough to avoid hunger pangs. This low-glycemic diet offers the nutritional benefits with variety yet balance. It leads to a healthy, happy, slim life style without going on yo-yo fad diets. The yo-yo of weight gain is propelled up more after going down because the low-fat diet reduces the metabolism level more than the other two diets do. You get lasting results with the Mediterranean-style without taking on the stress and health risks to your body of Atkins-style diets.

So once again, the Mediterranean-style diet celebrates colorful fruits and vegetables, tasty whole grains, golden drops of extra virgin olive oil, some fish and poultry, but very little red meat. It gives you variety and beauty.  In doing all of this, it offers all the nutrients that these foods provide, without the bad effects of eating excessive meat and fat and cutting out most carbs. We know that these beautiful and delicious foods, tastefully prepared, are healthy for us, so let’s enjoy them while, as a side benefit, we succeed in our weight management efforts.