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Eating the Atlantic Diet was linked to better health outcomes in a new study. Hispanolistic/Getty Images
  • People who followed the Atlantic Diet, a traditional way of eating in Portugal and Spain, were less likely to develop metabolic syndrome after 6 months, a new study showed.
  • Metabolic syndrome is a group of five health risk factors that can lead to diabetes, heart disease, stroke. They include high blood sugar, high blood pressure, and large waist circumference.
  • The Atlantic Diet emphasizes seasonal, local, fresh, and minimally processed foods such as vegetables and fruit, fish and seafood, and olive oil.

People who followed the Atlantic Diet, a traditional way of eating in parts of Portugal and Spain, lowered their chances of developing metabolic syndrome, a new study showed.

Metabolic syndrome is a group of five risk factors that can lead to diabetes, heart disease, stroke, and other health problems. A person is diagnosed with metabolic syndrome if three or more of these factors are present:

“This study showed benefits of the [Atlantic Diet] for multiple aspects of health, such as cholesterol levels, blood pressure, blood sugar control, and obesity,” said Dr. Cheng-Han Chen, an interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, Calif., who was not involved in the research.

“These results should not be surprising,” he told Healthline, “as the diet is very similar to the well-studied and beneficial Mediterranean diet.”

The study was published Feb. 7 in the journal JAMA Network Open.

The Atlantic Diet, also known as the Southern European Atlantic Diet, is a traditional dietary pattern of northern Portugal and northwestern Spain.

It’s similar to the heart-healthy Mediterranean Diet, but the Atlantic Diet has unique aspects drawn from the way people traditionally eat in certain parts of Portugal and Spain.

“These types of dietary patterns (Atlantic and Mediterranean Diets) have the potential to reduce the risk of heart disease, diabetes, cancer, stroke and even cognitive decline such as dementia and Alzheimer’s disease, and improve [gastrointestinal] function and the gut microbiome,” said Tracy Crane, PhD, RDN, co-Leader of the Cancer Control Research Program of the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine.

The Atlantic Diet emphasizes seasonal, local, fresh and minimally processed foods, including:

  • vegetables, fruits, cereals, whole grains and whole-grain bread, potatoes, nuts (in particular, chestnuts) and legumes
  • fish and seafoods
  • dairy products (mainly milk and cheese)
  • beef, pork, poultry, and wild game
  • olive oil
  • wine

Food preparation in this region involves simple cooking techniques such as boiling, grilling, baking, and stewing.

“The Atlantic Diet presents significant potential for enhancing health due to its emphasis on nutrient-dense foods and family-oriented eating habits,” said Michelle Routhenstein, MS, RD, a registered dietitian nutritionist who specializes in heart disease at

“By prioritizing wholesome ingredients and traditional cooking methods such as stewing, this diet enhances the bioavailability of nutrients, ensuring that the body can better absorb and utilize them,” she told Healthline.

In particular, stewing is an excellent heart-healthy cooking method, she said, because it preserves nutrients and flavors, and minimizes the formation of advanced glycation end products.

These compounds are created when certain foods are cooked at high temperatures, as with grilling and frying. They are “associated with oxidative stress and inflammation, factors linked to cardiovascular diseases,” said Routhenstein, who was not involved in the new research.

The study, which took place from 2014 to 2015, involved over 200 families recruited from a primary health care center in a rural town in northwestern Spain.

Families were randomly assigned to follow either the Atlantic Diet (121 families, including 270 adults) or their usual diet (110 families, including 248 adults).

All participants were of Spanish ethnicity and Caucasian descent, the average age was 47 years old, and about 60% were female. Families had on average two to three members.

People following the Atlantic Diet attended three nutrition education sessions and received additional support such as a cooking class, a recipe book, and free food baskets with foods typical of the diet.

At the start of the study and after 6 months, researchers collected information from participants on what they ate (using a 3-day food diary), physical activity, medication use, and other factors.

Researchers measured metabolic variables at the primary healthcare center: waist circumference, triglyceride levels, HDL cholesterol levels, blood pressure, and fasting glucose levels.

More than 450 participants did not have metabolic syndrome at the start of the study. Of these, 3% of the people following the Atlantic Diet developed metabolic syndrome after 6 months, compared to 7% of those following their usual diet.

Overall, people following the Atlantic Diet saw improvements in waist circumference, obesity around the middle, and HDL cholesterol — but not in blood pressure, triglyceride levels or fasting glucose levels.

“[The results] show that adhering to this diet can lead to improvements in various risk factors associated with cardiovascular disease and metabolic syndrome,” said Routhenstein.

“The emphasis [in the Atlantic Diet] on consuming nutrient-dense foods can contribute to better weight management and reduced waist circumference, further lowering the risk of cardiovascular issues,” said Routhenstein.

In addition, 117 participants started off with metabolic syndrome. After 6 months, about one-third of people in both groups no longer met these criteria. This suggests that the Atlantic Diet mainly benefitted people who had not yet developed metabolic syndrome.

However, 6 months may not be enough to “properly assess metabolic changes,” the researchers wrote in the paper.

A longer-term study published in 2021 in BMC Medicine, though, found that older adults in Spain who followed the Atlantic Diet more closely were less likely to die from any cause over an average follow-up of 11 years.

The new study had several strengths, including the large number of people who completed the study. The participants also mainly had moderate socioeconomic and educational levels, which may make the results relevant to more people.

Researchers, though, were unable to take into account all factors that might affect a person’s risk of developing metabolic syndrome.

In addition, participants in the Atlantic Diet group received food baskets, which made it easier for them to stick with the diet. However, people in the real world don’t have that extra support, so they may be less likely to follow the diet.

Research from the real world suggests that people may be able to follow parts of this dietary pattern even without free food baskets.

An earlier survey of older adults in northwestern Spain and northern Portugal, published in 2022 in the Journal of Functional Foods, found that people’s adherence to the Atlantic Diet was “medium-high.”

However, the study showed that this group was less likely to follow the nuts, wine, and fish and seafood characteristics of the diet, although most of them ate dairy products and olive oil every day.

One key aspect of the Atlantic Diet is its emphasis on seasonal, local foods, which differ from region to region. But even if you don’t have the same kinds of local foods in your area, Chen said the general principles of the Atlantic Diet can guide you toward healthy eating.

“In particular, the diet emphasizes a variety of fresh and seasonal foods, including vegetables, fruits, whole grains, beans, nuts, fish, seafood and meat — which are all nutritious and healthy components of a balanced diet,” he said.

“In addition, its emphasis on foods that are minimally processed is a lesson we can incorporate into our eating habits,” he said.

Crane agrees: “The takeaway is if people generally follow a plant-based diet — high in vegetables, fruit, healthy sources of fat, legumes and protein — it can improve a variety of risk factors for several chronic diseases,” she told Healthline.

“This study is one in a long line of studies demonstrating the benefits of this type of dietary pattern,” she added.

Another aspect of the study that Routhenstein thinks is useful is the emphasis on introducing the Atlantic Diet to families.

“By prioritizing shared meals and dietary habits within the family unit, individuals are more likely to adhere to healthier eating patterns,” she said. “This family-centric approach not only promotes the consumption of nutrient-dense foods but also fosters positive social interactions around mealtime.”

In a new study, researchers randomly assigned people to follow either the Atlantic Diet or their usual dietary patterns. This is a traditional way of eating in Portugal and Spain that emphasizes seasonal, local, fresh, and minimally processed foods.

After 6 months, people on the Atlantic Diet were less likely to develop metabolic syndrome, a set of risk factors for diabetes, heart disease, stroke, and other health problems.

They also saw improvements in waist circumference, obesity around the middle, and HDL (“good”) cholesterol, but not blood pressure, triglyceride levels or fasting glucose levels.