• The Atlantic diet, founded in the eating patterns of Portugal and Spain, could improve metabolic health, a new study found.
• Similar to the Mediterranean diet, the Atlantic diet emphasizes high consumption of fresh and local fruits, vegetables, olive oil, and fish.
• The eating plan may be especially helpful for people at risk of developing metabolic syndrome, such as those with overweight or obesity or older people.

The Atlantic diet is making a name for itself in the research world, and could rival the Mediterranean diet as an alternative way to significantly boost overall health.

Based on the eating patterns of people in northwest Spain and northern Portugal, the Atlantic diet is characterized by high consumption of fresh and local seafood, vegetables, olive oil, and more.

Eating these foods seems to improve various measures of metabolic health, according to a new study published in early February in JAMA Network Open. After a 6-month dietary intervention, Spanish families who followed a traditional Atlantic diet and received educational sessions, cooking classes, and other support, had a lower risk of developing metabolic syndrome than those who did not receive this intervention.

Metabolic syndrome is a group of conditions—high blood pressure, high triglycerides, high blood sugar, a large waistline, and/or low HDL cholesterol—that can raise a person’s risk of diabetes, stroke, and other health issues. It’s a major health concern in the U.S., and it affects about one in three American adults.

The diets of northern Spain and Portugal have long been noted for their potential health benefits, but the new study is the first to examine them in a real-world context.

“Research...has traditionally been conducted solely from a theoretical perspective, without utilizing real food consumption data from individuals or in real-life scenarios,” Mar Calvo-Malvar, PhD, study author and laboratory medicine specialist at the University Clinical Hospital of Santiago de Compostela, told Health.

The new study sought to put theory into practice—with intriguing results.

Here’s what experts had to say about the Atlantic diet, why it has such a positive effect on metabolic health, and whether it’s worth a try.

What Is an Atlantic Diet?

Due to their geography, the cuisines of Spain and Portugal bear many similarities to those of the Mediterranean.

“Like the Mediterranean diet, the Atlantic diet emphasizes the consumption of fresh, seasonal, and locally sourced foods such as fruits, vegetables, cereals...fish, and dairy products,” Calvo-Malvar explained. Using plenty of olive oil is another commonality between the two. 

However, the diets have some notable differences that stem from regional history.

“The Atlantic diet origins trace back to the Celtic peoples inhabiting the European Atlantic Arc, encompassing areas such as northern Spain, northern Portugal, Ireland, Scotland, Wales, southern England, the Isle of Man, and the French region of Brittany,” said Calvo-Malvar.

This makes the Atlantic diet distinct—it typically features a greater proportion of fish, milk, potatoes, fruits, and vegetables as compared to the Mediterranean diet, Calvo-Malvar said. People in northern Spain and Portugal also generally have a higher intake of wine and a lower consumption of beer.

Beyond the food itself, cooking techniques are another way the Atlantic diet is set apart from its Mediterranean counterpart.

“The cooking techniques associated with the Atlantic diet, such as steaming, boiling, baking, grilling, or stewing, result in less modification of the nutritional composition of foods, compared to frying,” said Calvo-Malvar.

In general, the Atlantic diet features:

• High consumption of fish, mollusks, crustaceans, vegetables, potatoes, bread, cereals, fruits, chestnuts, legumes, honey, whole nuts, and olive oil
• Moderate consumption of wine, milk, cheese, eggs, pork, and beef
• Lower consumption of fatty meats, sweets, and soft drinks

What Are the Health Benefits of an Atlantic Diet?

Since the JAMA Network Open study is the first to examine an Atlantic diet’s real-world effects, it’s just an initial peek into the possible applications of this eating plan. But according to this research, the diet could improve several components of metabolic wellness and heart health.

Over a duration of six months, 231 families in the rural town of A Estrada, Spain, were randomized to either receive educational sessions, cooking classes, written supporting material, and foods characteristic of the Atlantic diet, or to continue with their usual eating habits. 

At the end of six months, only 2.7% of those who received an Atlantic diet intervention developed metabolic syndrome, whereas 7.3% of those in the control group developed this condition.

The intervention also reduced the risk of central obesity and low HDL cholesterol, two important components in metabolic health. However, the Atlantic diet had no significant effect on participants' high blood pressure, high triglyceride levels, or high fasting blood sugar levels.

Participants in the Atlantic diet group also saw a decrease in waist circumference, which could be indicative of larger ripple effects for metabolic health, Calvo-Malvar said.

“It is worth noting that weight loss has been widely recognized as beneficial for treating all components of metabolic syndrome, including excessive [body fat], [cholesterol imbalance], hypertension, insulin resistance, and hyperglycemia,” she said.

As for why the Atlantic diet seems to have such a significant impact on people’s health? It likely has to do with a high intake of plant-based foods and healthy fats (especially olive oil), said Anne Danahy, RDN, author of The Mediterranean Diet Cookbook for Two.

“These can promote a healthier metabolic profile because of their fiber, antioxidants, and other nutrients,” she told Health. “As a whole, it’s a very anti-inflammatory diet.”

The addition of education and other support for the families following the Atlantic diet was another unique element that may have influenced health outcomes in the study.

“I think family education matters because it’s easier to stick to a healthy eating pattern when everyone in the house understands the benefits and eats the same way,” said Danahy. “When people in the household start to feel better and notice health benefits, they’re often encouraged to make further changes.”

Should You Try an Atlantic Diet?

Future research may shed more light on an Atlantic diet’s benefits for health. But for now, the results of this JAMA Network Open study seem promising. It could be worth trying an Atlantic diet, particularly if you’re at risk of developing metabolic syndrome, Calvo-Malvar said.

This could include shift workers, older people, and smokers, as well as people who get poor sleep or little exercise. Those with overweight or obesity, a family history of diabetes or metabolic syndrome, and PCOS may also be at a higher risk of metabolic syndrome.

But for anyone who’s interested in trying an Atlantic diet, it’s hard to go wrong when following any traditional diet pattern, said Danahy. The beauty of these kinds of eating plans is that they can be quite flexible.

“I think it’s important to not stress any one-size-fits-all way of eating. I like the idea of choosing parts of these traditional diets that appeal to you or have the most health benefits and crafting your personal way of eating,” she said. “If you can do that, you’ll be more likely to stick with it for the long term.”