How many calories are in oysters?

Fresh raw oysters contain approximately 81 kcal per 100g, or around 68 kcal for a serving of 6 medium oysters (84g). This makes them a low-calorie, high-protein food. However, canned smoked oysters in oil (like John West) are significantly higher at 230 kcal per 100g due to the added sunflower oil — nearly three times the calories of fresh.

Are oysters high in zinc?

Oysters are the single richest dietary source of zinc in any common food. Fresh oysters contain approximately 78mg of zinc per 100g — over 700% of the daily recommended intake. Just 2-3 oysters would meet your entire daily zinc requirement. They are also very high in iron, vitamin B12, copper, and selenium, making them one of the most nutrient-dense foods per calorie.

Can you buy oysters at Tesco?

Fresh oysters at Tesco are seasonal and typically available at the fish counter during autumn and winter months (roughly September to April). Availability varies by store. The most consistently stocked oyster product is John West Smoked Oysters in Sunflower Oil (85g, £2.65), which is a canned NOVA 3 product. For fresh oysters, check the fish counter or order online when in season.

What is the glycemic index of oysters?

Oysters has a glycemic index of 0, which is classified as Low GI. Oysters contain negligible carbohydrates, so they have no measurable glycemic index.

Glucose: Very LowNOVA 1

Nutritional Information for Oysters

Oysters are a nutrient-dense shellfish providing around 81 kcal per 100g with 9g of protein and exceptionally high levels of zinc (78mg per 100g — over 700% of the daily recommended intake). From a SpikeSaver perspective, oysters contain only around 5g of carbohydrates per 100g, producing a very low glucose response. Fresh oysters are NOVA 1. Note: Tesco's range for actual oysters is extremely limited — batch data mostly returned Oyster Bay wines (not food). The one genuine oyster product found was John West Smoked Oysters in sunflower oil. Nutritional values below are based on USDA reference data for raw Pacific oysters.

Nutrition per 100g

Nutrient	Per 100g	Per serving
Energy	81 kcal / 339 kJ	68 kcal
Protein	9g	7.6g
Carbohydrates	5g	4.2g
of which sugars	0.5g	—
Fat	2.3g	1.9g
of which saturated	0.5g	—
Fibre	0g	—
Salt	0.26g	—

Serving size: 6 medium raw oysters (~84g) · Source: USDA FoodData Central; Tesco product page, October 2025

Glucose impact

Glycemic Index

Very Low

Glucose risk

Oysters contain only about 5g of carbohydrates per 100g, with minimal sugars. The carbohydrate present is largely glycogen (animal starch) rather than simple sugars. Combined with their high protein content, oysters produce a very low blood glucose response. They are safe for anyone managing blood sugar levels.

Processing level

NOVA 1 (unprocessed)

Fresh raw oysters are an unprocessed single-ingredient food. They are typically consumed raw or lightly cooked with no additives. Canned or smoked oysters (such as John West Smoked Oysters) move to NOVA 3 as they undergo smoking, are preserved in oil, and have added salt.

Oysters at Tesco

Source: USDA FoodData Central; Tesco product page, October 2025

John West Smoked Oysters Sunflower Oil 85G

1 UPF marker

£2.65*NOVA 3 (processed)

*Prices were correct at the time of collection and may have since changed. Check Tesco.com for current pricing.

What to watch for when shopping

Fresh oysters are a seasonal product at Tesco and may not always be available — check the fish counter during winter months (September-April) when they are in season. The batch data for this page mostly returned Oyster Bay branded wines, not food products. The only genuine oyster product consistently stocked is John West Smoked Oysters in Sunflower Oil (NOVA 3), which is significantly higher in calories (230 kcal/100g) due to the added oil and contains 14g fat per 100g compared to 2.3g in fresh oysters. Oysters are extraordinarily rich in zinc (78mg/100g fresh), iron, vitamin B12, and selenium. If buying canned, drain the oil to reduce fat content.

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