Switching up the foods you eat and eliminating bad ingredients can drastically improve your health and longevity. It all depends on your individual needs, as different people may react in different ways to the same foods. (That's why it's usually a good idea to check with your doctor first.)

But one diet that has gained popularity in recent years is the Mediterranean diet. In fact, it was recently ranked as first in overall best diets for the fourth year in a row, according to U.S. News & World Report's annual list.

As a nutritionist, I often recommend trying to incorporate foods from the Mediterranean-style diet — which is high in vegetables, fruits, olive oil and whole grains, and moderate in protein and animal fats — into your eating routine. Research suggests that primary foods in this diet can help ward off chronic diseases and improve longevity. Another study found there may also be benefits for the brain.

Here are five staple Mediterranean diet foods I've been eating to stay healthy and strong:

1. Oats

By improving the intestinal transit of food and waste, fiber helps your body eliminate carcinogens. Unfortunately, an estimated 95% of American adults and children don't consume enough fiber, according to a 2017 analysis published in U.S. National Library of Medicine.

Oats are my go-to for fiber-rich foods. The gluten-free whole grain is a great source for important vitamins, minerals and antioxidants. When slow-cooked, it provides a balanced portion of fats, carbohydrates and plant protein, along with good doses of iron and B vitamins.

In a study last year, researchers found that higher intakes of fiber resulted in decreased mortality from cardiovascular and respiratory diseases. The American Heart Association Eating Plan suggests that total dietary fiber intake should be between 25 to 30 grams a day (from food, not supplements). 

Oats are also a staple for Adventists, a small community in Loma Linda, California who researchers have found live up to a decade longer than other Americans.

My breakfast often consists of classic oatmeal with fruit, but oats can be prepared in a savory style, too. You can use it as coating in place of breadcrumbs, or in a hearty risotto in place of rice.

2. Extra virgin olive oil

Not all liquid oils (for cooking or cold preparations) are the same. Many nutritionists and health experts recommend that your first choice be extra virgin olive oil.

Extra virgin olive oil contains mainly monounsaturated fat in the form of oleic acid, along with high amounts of antioxidants — both of which researchers say can help reduce biomarkers of inflammation.

A 2020 study published in the Journal of the American College of Cardiology found that individuals who consumed half a tablespoon or more of extra virgin olive oil per day had a 14% lower risk of cardiovascular disease and an 18% decrease in coronary heart disease risk. Replacing five grams per day of other fats (e.g. butter or margarine) with olive oil also lowered the risk of total cardiovascular disease and coronary heart disease by 5% to 7%.

My favorite way to incorporate extra virgin olive oil is to drizzle a small amount over vegetables like broccoli, cauliflower or carrots before roasting them in the oven.

3. Fish

Fatty fish like tuna, salmon, herring and lake trout contain high amounts of healthy omega-3 fatty acids, which research has shown can improve your cardiovascular health.

If you're a fish lover like me, the American Heart Association recommends adults eat two servings of fish — particularly the fatty kind — per week, with a serving being 3.5 ounces of cooked fish or roughly ¾ cup of flaked fish. (The U.S. Food and Drug Administration advises that children and pregnant women avoid eating fish with potential for the highest level of mercury contamination, such as shark, swordfish, king mackerel and tilefish.)

Want to get creative with fish? Try using it in place of beef or chicken in your tacos. Salmon patties are also a must-try. Remember to balance your plate with lots of vegetables, fruit, whole grains and other healthy fats as well. 

4. Green leafy vegetables

Leafy vegetables, such as spinach, romaine and kale, are another aspect of the Mediterranean diet. They're filled with essential nutrients — vitamin A, vitamin C, folate, vitamin K, iron, calcium and potassium.

The amount of vegetables you need, which can vary between one and three cups per day, depends on your age, sex and level of physical activity. In general, according to the U.S. Department of Agriculture (USDA), one cup of vegetables is equivalent to a cup of raw or cooked vegetables or vegetable juice, or two cups of raw leafy greens.

Make yourself a fresh salad with a variety of leafy vegetables for a mix of nutrients and flavor. You can also add them to whole grain pastas or soups. To get a green kick that will instantly wake me up, I like throwing some kale into my breakfast smoothies.

5. Berries

Although there are several essential fruits in the Mediterranean diet, berries — especially blueberries and strawberries — rank high on my list of favorites, due to their rich levels of antioxidants.

Berries also have lots of anthocyanins, a type of flavonoid. Research suggests that anthocyanins can have several positive effects on the body, including lowering blood pressure and making blood vessels more elastic.

Dr. Eric Rimm, associate professor at the Harvard School of Public Health and Harvard Medical School, has done a significant amount of research backing the benefits of berries. He recommends three or more servings of a half-cup of blueberries or strawberries each week. One cup of whole strawberries will provide you with almost 100% of your daily vitamin C needs, according to the USDA.

I usually start the day with blueberries in my yogurt, cereal or oatmeal. And my salads are never complete without berries (along with sunflower seeds, nuts and beans for added protein).

Lauren Armstrong is a registered dietitian and personal nutrition coach. Formerly, she worked as a nutritionist for the Women, Infant and Children (WIC) program. Lauren received her bachelor's degree in dietetics from Western Michigan University, and has written for several publications, including Livestrong and HealthDay. Follow her on Instagram @laurenarmstrong.rdn.

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