A single medium raw oyster contains roughly 7 to 10 calories, depending on the species and size. That makes oysters one of the lowest-calorie protein sources you can eat. A typical serving of six medium oysters clocks in at about 43 to 60 calories, with the number climbing only when you add breading and oil.
Calories by Species
The two most common oyster species sold in the U.S. have slightly different nutritional profiles, though both are remarkably lean. Eastern oysters (the variety dominant on the Atlantic and Gulf coasts) provide about 43 calories per six medium oysters, with 4.8 grams of protein and 1.4 grams of fat. Pacific oysters, common on the West Coast, run a bit larger individually. A single medium Pacific oyster weighs around 50 grams and contains about 41 calories, 4.7 grams of protein, and 1.2 grams of fat.
Both species carry a small amount of carbohydrate, around 2 to 2.5 grams per serving, which is unusual for an animal protein. That comes from glycogen stored in the oyster’s tissue. Neither species contains any fiber, and saturated fat is minimal at under half a gram per serving.
How Cooking Changes the Count
Raw or steamed oysters stay in the same calorie range. Six medium oysters, whether eaten on the half shell or gently steamed, come to about 60 calories. Steaming doesn’t add fat, so the numbers barely budge.
Frying is a different story. Breading and oil nearly triple the calorie count. Six breaded and fried oysters contain roughly 175 calories. Most of that increase comes from the flour or cornmeal coating absorbing oil during cooking. If you’re watching calories but still want a cooked preparation, grilling or broiling with a light brush of butter keeps you much closer to the raw calorie count.
The FDA lists a 3-ounce cooked portion (about 12 medium oysters) at 100 calories, 4 grams of fat, and 6 grams of protein. That 3-ounce figure is the standard reference serving for seafood, so you’ll see it on restaurant nutrition panels and packaged products.
What Else You Get per Oyster
Oysters pack a surprising amount of nutrition into those few calories. They’re one of the richest food sources of zinc, which supports immune function and wound healing. A single serving can deliver several times your daily zinc requirement. They’re also high in vitamin B12, iron, copper, and selenium.
The omega-3 content is notable too. Pacific oysters provide about 0.69 grams of EPA and DHA (the omega-3 fats linked to heart and brain health) per 100 grams of raw meat. That puts them in a similar range to many fin fish, though below salmon and sardines. For a food this low in calories, that’s an impressive concentration of beneficial fats.
Cholesterol is moderate. Six medium Eastern oysters contain about 34 milligrams, and a medium Pacific oyster has around 25 milligrams. For context, dietary guidelines no longer set a strict daily cholesterol cap, and the amounts in oysters are well below what you’d find in a single egg.
Figuring Out Your Portion
Oyster sizes vary widely. A medium oyster’s edible meat weighs roughly 12 to 14 grams for Eastern varieties and around 50 grams for a medium Pacific oyster, which tends to be a physically larger animal. When you see calorie counts online, check whether they refer to a single oyster or a batch of six or twelve, because the numbers can look confusing otherwise.
At a raw bar, a typical order is six or twelve oysters. Six Eastern oysters give you about 43 calories. Twelve gets you to roughly 85 to 100 calories, still less than a single slice of bread. If you’re eating Pacific oysters, which are meatier per piece, expect closer to 40 calories each. Two medium Pacific oysters provide about 82 calories, 9.4 grams of protein, and 2.4 grams of fat.
For people tracking macros, oysters are unusual in that they offer a near-even split of protein, fat, and carbohydrate by gram weight rather than the protein-dominant profile of most seafood. The total amounts are so small per oyster, though, that this balance rarely matters in practice. What stands out is the protein density relative to calories: you get almost 5 grams of protein for every 40 to 45 calories, making oysters one of the most efficient protein-per-calorie foods available.