Q: What makes sushi so healthy?

For starters, sushi is low in calories - there is no added fat. The most common type is nigiri sushi - fingers of sticky rice topped with a small filet of fish or seafood. On average, one piece of sushi nigiri has about 70 calories. A typical order of 6 pieces provides 310 to 420 calories, depending on the type of fish.

Maki sushi are rolls are made with sticky rice, fish and dried seaweed, called nori. Most maki places the nori on the outside, but California rolls place the rice on the outside. On average, one piece of maki roll has 48 calories. A typical order of 6 pieces, or one roll, contains 250 to 370 calories, depending the type of fish and whether or not it's made with avocado.

Sashimi is simply raw fish served sliced without rice. A three ounce portion -- about 6 pieces -- has on average, 132 calories.

Sushi is a good source of heart healthy omega-3 fatty acids form the fish it's made with. Plenty of studies have determined that eating fish at least twice a week is linked with a lower risk or heart attack and stroke and may even keep your brain healthy as you age.

Q: If you're watching calories, are there any types of sushi you should stay clear of?

Some types of sushi are higher in calories than others. Rolls made with tempura shrimp like Dynamite rolls are higher in fat and calories because the shrimp is deep fried. Spider rolls have mayonnaise so they will be a little higher in fat and calories too. Rolls with avocado are also higher in fat, but keep in mind that avocado contains heart healthy monounsaturated fat.

If you are concerned about calories, the most important strategy is portion size. It's easy to eat a lot of sushi because it's not particularly filling. If you are trying to lose weight, I advise women stick to 6 pieces and men stick to 9 pieces -- along with miso soup and salad.

Q: What's the downside -- any risks from eating sushi?

One concern is the high amounts of mercury in some species of fish. Women who are planning to become pregnant, who are pregnant, who are breastfeeding and young children should limit or avoid high mercury fish which include tuna, king mackerel, swordfish, shark, tilefish, and orange roughy. You find all of these at a sushi restaurant, but tuna and mackerel are common. The concern is that too much mercury may damage a baby's developing brain and nervous system.

People with weakened immune systems and pregnant women need to be very cautious when it comes to eating raw fish of any type. There is chance, albeit slim, that raw fish can harbor parasites. Because pregnancy suppresses the immune system a little, women are much more susceptible to food poisoning. Although the chances are slim of getting sick from eating sushi, the consequences are severe enough that it's best to play it safe and avoid raw fish.

If you love sushi, order it from a reputable restaurant. Ask if the fish has been previously frozen, because commercial freezing of fish kills parasites (home freezers are not cold enough to kill parasites.)

Or order sushi that does not contain raw fish. Many types of sushi contain steamed or cooked fish; some are served warm others are served cold.

Q: What about the sodium? Is light soy sauce better?

Yes, if you enjoy dipping your sushi in soy sauce or you love teriyaki, sodium can certainly be an issue especially if you have high blood pressure. One tablespoon of regular soy sauce has 900 milligrams of sodium - close to half of an entire day's worth. Lite soy sauce has about 25% less sodium: 600 milligrams per tablespoon. Teriyaki glaze or marinade contains roughly 500 milligrams of sodium per tablespoon. So go easy if you are watching sodium.

Q: How healthy are other items on the menu at a Japanese restaurant?

There are many healthy foods to order.

  • Edamame -- steamed or boiled green soy beans which are high in protein and an excellent source of phytoestrogens, natural compounds that may help reduce the risk of heart disease and breast and prostate cancers.
  • Seaweed salad -- is low in calories and fat and is a good source of calcium and iodine.
  • Green tea -- contain an incredibly high concentration of a phytochemicals called catechins, potent antioxidants that appear to help lower the risk of heart disease and numerous types of cancer. Green tea has about three times the quantity of catechins found in black tea.