Is Eating Sushi Healthy? Plus the Best and Worst Sushi to Order

Made with rice and seafood, sushi is a good source of nutrients. Unfortunately, even the healthiest sushi rolls can pack a lot of carbs. On top of that, undercooked fish and seafood may be contaminated with bacteria and lead to foodborne illnesses.

This traditional Japanese dish is becoming increasingly popular in the U.S. Since it's made with fish, rice and seaweed, it's considered healthy. Its nutrition value, though, depends on the ingredients used and portion size, which may vary greatly from one restaurant to another.

Nigiri sushi, for example, has 47 calories, 2 grams of protein, 7.8 grams of carbs and less than 1 gram of fat per ounce, depending on the recipe. This dish typically consists of two pieces of sushi, but it can also include six, eight or even 12 pieces. If you eat everything at once, the calories will add up.

Vegetable sushi, by comparison, provides about 19 calories, 2.4 grams of carbs, 0.8 grams of fat and 0.8 grams of protein per ounce. RA Sushi, a popular Japanese restaurant, lists the following nutritional values for its sushi recipes:

• Tootsy maki — 420 calories, 14 grams of fat, 61 grams of carbs, 9 grams of protein and 1,360 milligrams of sodium per serving (7.75 ounces)
• Lunch sushi assortment — 590 calories, 23 grams of fat, 74 grams of carbs, 18 grams of protein and 1,250 milligrams of sodium per serving (11 ounces)
• Albacore tuna nigiri sushi — 60 calories, 9 grams of carbs, 6 grams of protein and 130 milligrams of sodium per serving (1.7 ounces — 2 pieces)
• Flying fish nigiri sushi — 70 calories, 15 grams of carbs, 2 grams of protein and 260 milligrams of sodium per serving (1.5 ounces — 2 pieces)
• Maki sushi avocado roll — 370 calories, 20 grams of fat, 42 grams of carbs, 5 grams of protein and 420 milligrams of sodium per serving (7.4 ounces)

With a few exceptions, sushi calories are not a reason for concern. If you're on a diet, avoid sushi rolls made with fried ingredients, sauces or mayo.

White rice, the main ingredient in this dish, should be consumed with caution by those who are at risk for diabetes. A review published in the journal Heart Asia in August 2017 reports that white rice may contribute to the onset of metabolic syndrome in certain populations when consumed regularly. Researchers didn't find a direct association between this grain and diabetes, stroke or heart disease, but other studies indicate the opposite.

For example, a February 2015 review featured in ARYA Atherosclerosis indicates a strong link between white rice consumption and cardiovascular risk factors, such as diabetes and metabolic syndrome. Brown rice, on the other hand, may help protect against these diseases due to its high fiber content.

Read more: 9 Poke Bowls That Will Make You Forget About Sushi

Fish and seaweed, other key ingredients in sushi, are high in protein and low in carbs. Tuna, salmon and other fatty fish boast large doses of omega-3s and may help lower your risk of stroke and cardiovascular problems, states the American Heart Association. The downside is that most types of fish and seafood used in sushi are undercooked and may contain high levels of mercury.

Whether sushi is healthy comes down to the ingredients used and how much you eat. Some varieties are healthier than others and have just a few calories per serving. While fish is a good source of protein and omega-3 fatty acids, other ingredients, such as white rice and sodium, can add up and harm your health in the long run.

This traditional Japanese dish is often made with raw fish or seafood and can harbor bacteria, such as Salmonella. The Academy of Nutrition and Dietetics warns about the dangers of Vibrio vulnificus, a disease-causing bacterium that may occur in undercooked fish. In 2014, it infected over 1,200 people in the U.S. alone.

Certain individuals, such as children, seniors, pregnant women and people with a weak immune system, are advised to avoid raw or undercooked fish and seafood. If you fall into any of these categories, stay on the safe side and avoid any type of sushi containing raw fish.

Read more: 13 Types of Fish to Avoid Eating

Another problem is the mercury in bluefin or yellowfin tuna, swordfish, mackerel, bonito and other types of fish used in sushi recipes. The American Pregnancy Association recommends that expecting moms avoid undercooked and high-mercury fish.

Some sushi varieties are safe, though. If you're pregnant, you may eat up to two 6-ounce servings of the following sushi varieties each week:

• Ebi (shrimp)
• Sake (salmon)
• Tai (sea bream)
• Kani (crab)
• Uni (sea urchin roe)
• Tako (octopus)
• Masu (trout)
• Hatahata (sandfish)

Whether you're concerned about sushi calories or food poisoning, you can still enjoy this flavorful dish as long as you know what to look for. Also, skip the sauces and dressings, which can be high in sugar, fat and calories.

Read more: 9 Excuses to Eat More Seafood (Hint: It Can Make You Happy!)

If possible, ask for brown rice or sesame seeds instead of white rice in sushi rolls. Order sushi varieties made with salmon, trout, crab and other low-mercury seafood. The safest options are those containing cooked fish or vegetables, such as eel and ebi, according to the University of California. Beware that "American" sushi may contain foie gras, cream cheese, mayo and other fat-laden ingredients.

Sushi is typically high in sodium — and soy sauce only makes things worse. Some varieties, such as tootsy maki, boast up to 1,360 milligrams of sodium per serving.

To cut down on salt, swap sushi for sashimi and use low-sodium soy sauce. California rolls, for example, are relatively healthy. One piece (1 ounce) has about 28 calories, 5.5 grams of carbs, 0.2 grams of fat, 0.8 grams of protein and just 129 milligrams of sodium, depending on the ingredients. Serve it with wasabi or Japanese horseradish, which boasts antimicrobial and antioxidant properties.

Nigiri, sashimi, rainbow rolls, vegetarian rolls and California rolls are some of the best choices due to their low mercury content. Plus, they're made with avocado, egg whites, crab meat, cucumbers and other ingredients that may benefit your health.