This Study Says This Is the Healthiest Diet in the World
What’s the healthiest diet one can eat? A study claims to have finally found the answer.
That’s not such an easy task, considering there are so many hyped diets out there. Chances are you know somebody who’s adopted a keto, paleo, pescatarian, or vegan diet in recent years—if that wasn’t you yourself.
But a 2023 study looked at how healthy six of the most common diets are and compared how they affect not only the body, but also the environment. The researchers used data from a statistical survey by the National Health and Nutrition Examination Survey (NHANES). In the study, 16,800 adults were asked about their diet between 2005 and 2010. If participants could not be clearly assigned to one type of diet, they were excluded. The researchers were able to categorize the remaining results into six of the most common diets, from vegan to pescatarian to omnivorous.
The most common diets, according to the study
The study examined six common diets that emerged from the survey. Those were:
- Vegan: Vegans eat an exclusively plant-based diet and avoid animal products.
- Vegetarian: Vegetarians do not eat meat or fish, but will eat animal products like milk and eggs.
- Pescatarian: Pescatarians eat fish, seafood, and other animal products such as eggs and milk, but no meat.
- Paleo: This diet is based on the Stone Age, before humans became sedentary. Meat, eggs, and nuts are on the menu.
- Keto: In the ketogenic diet, over 80 percent of calories come from healthy fats and the diet all but eliminates carbohydrates.
- Omnivorous diets: This is how the study categorized all other diets, which more or less include all the food groups.
How the researchers evaluated the individual diets
To determine which diet is the healthiest—both for you and the planet—the scientists evaluated the dietary information according to quality and climate footprint. In terms of quality, or how healthy the diet is, points were awarded for certain food groups. The higher the score, the closer the diet is to the recommendations for a healthy diet in general. The average greenhouse gas emissions of each diet were also taken into account.
And the healthiest diet is…
The diet with the highest score in terms of health and environmental impact is the pescatarian diet. This is also consistent with other studies that have found that people who eat fish regularly live longer on average. This is mainly due to the omega-3 fatty acids fish contains, which can help lower your blood pressure and thus lower the risk for cardiovascular diseases and blood clots.
The pescatarian diet was closely followed by the vegetarian and vegan diets, with their emphasis on plant-based foods, while the lowest scores went to the paleo and keto diets. These results are generally in line with the Dietary Guidelines for Americans, which recommends prioritizing fruits, vegetables, whole grains, dairy, and lean proteins like seafood, poultry, eggs, legumes, nuts, seeds, and soy products.
In terms of carbon footprint, the vegan diet scored best followed by the vegetarian diet. The meat-heavy paleo and keto diets fared the worst.
The benefits of a pescatarian diet
Interested in becoming a pescatarian now? We asked Tamar Samuels, MS, RD, and the cofounder of Culina Health, about some of the diet’s benefits.
“A well-planned pescatarian diet offers numerous health benefits, mainly due to the nutritional value of fish and the inclusion of plant-based foods,” the expert says. “Fish is an excellent source of high-quality protein, providing essential amino acids necessary for muscle maintenance, immune function, and overall health.”
- Fish is rich in omega-3 fatty acid content. “One of the most significant benefits of consuming fish is its rich omega-3 fatty acid content, particularly EPA (eicosatetraenoic acid) and DHA (docosahexaenoic acid),” Samuels says. “These essential fats play a crucial role in heart health by reducing inflammation, lowering triglycerides, and supporting healthy blood pressure levels. Omega-3s are also vital for brain function, contributing to cognitive health, reducing the risk of neurodegenerative diseases, and supporting mental well-being. Additionally, DHA is essential for fetal brain development during pregnancy, making fish consumption particularly beneficial for expecting mothers.”
- A lower risk for cardiovascular disease and better long-term health. “Pescatarians tend to have a more favorable cardiovascular risk profile, including lower BMI, cholesterol, and hypertension levels compared to omnivores,” says Samuels. “This diet is also linked to lower DNA damage than vegetarian diets, which may contribute to better long-term health outcomes.”
- Better eye health over time. “Regular fish consumption in a pescatarian diet is associated with reduced risk of visual impairment, such as age-related macular degeneration,” Samuels adds.
Pescatarian diet risks
For all its many benefits, Samuels recommends being mindful about making sure you can still get all the nutrients you need before adopting a pescatarian diet as there are risks involved. Talk to a doctor about your dietary requirements if you have any questions or concerns.
“Without careful planning, pescatarian diets can lead to deficiencies in nutrients like iron, particularly in women of reproductive age,” the expert explains. “A well-planned pescatarian diet offers numerous health benefits, but several key considerations should be kept in mind to ensure optimal nutrition and minimize potential risks.” Some of those are:
- Nutrient balance. “One important factor is nutrient balance—while fish provides high-quality protein and essential omega-3 fatty acids, a pescatarian diet should also include a variety of plant-based foods, such as legumes, whole grains, nuts, and seeds, to ensure adequate fiber, vitamins, and minerals,” Samuels says.
- Mercury exposure. “Another critical factor is mercury exposure, as some fish contain high levels of mercury, which can be harmful, particularly for pregnant women and young children,” says Samuels. “To reduce risk, it is advisable to prioritize low-mercury seafood options such as salmon, sardines, trout, and shrimp while limiting intake of high-mercury fish like tuna, swordfish, and king mackerel.”
- The sustainability of seafood choices. “Beyond individual health concerns, the sustainability of seafood choices is an important consideration,” advises Samuels. “Overfishing and unsustainable fishing practices contribute to environmental damage, so opting for seafood certified by organizations like the Marine Stewardship Council (MSC) or following recommendations from guides such as the Monterey Bay Aquarium’s Seafood Watch can help reduce ecological impact.”
A version of this post was previously published in Glamour Germany.
