Keto Tuna Steak with Sesame Crust
This keto tuna steak with sesame crust brings Japanese-inspired flavor to your plate in just 10 minutes. A crisp coating of black and white sesame seeds surrounds the pink center of the tuna, served with wasabi mayo and soy sauce as dips. With around 42 g of protein and only 2 g of net carbs, it is one of the fastest and most protein-rich keto dinners you can make.
Key facts at a glance
- Prep time: approx. 10 minutes, the fastest keto dinner with fresh fish.
- Approx. 2 g net carbs and 28 g fat per serving.
- Ingredients: tuna steak, black and white sesame seeds, sesame oil, mayonnaise, wasabi paste, soy sauce.
- Works as a quick keto dinner or a light main course, especially for fish and sushi lovers.
Ingredients
One serving is intended as a light keto dinner; if you need more calories, double the mayonnaise or use a second steak.
| Amount | Ingredient | Note | ||
|---|---|---|---|---|
| Tuna steak (sushi grade) | - | |||
| Sesame seeds (black and white mixed) | approx. 2 tbsp | |||
| approx. 2 tbsp | ||||
| Sesame oil | approx. 10 g; approx. 1 tbsp | |||
| approx. 10 g; approx. 1 tbsp | ||||
| Mayonnaise | approx. 2 tbsp | |||
| approx. 2 tbsp | ||||
| Wasabi paste | approx. 1 tsp | |||
| approx. 1 tsp | ||||
| Soy sauce | approx. 1 tbsp | |||
| approx. 1 tbsp | ||||
Preparation
Mix the sesame seeds on a plate and press the tuna steak into them on all sides. Sear in hot sesame oil for just 60 to 90 seconds per side. Stir together the wasabi mayo and serve with soy sauce.
Why tuna steak fits a keto diet
Tuna is a virtually carb-free food with an outstanding nutritional profile: 100 g of fresh tuna provides around 23 g of protein and 5 g of fat with zero carbs. It also delivers valuable omega-3 fatty acids (EPA and DHA), which are particularly relevant on a ketogenic diet because they have anti-inflammatory effects and support heart health. The sesame crust adds healthy unsaturated fats: 2 tbsp of sesame (approx. 18 g) provides around 9 g of fat and only 0.4 g of net carbs. The sesame oil used for searing adds another 5 g of fat. The wasabi mayo made from mayonnaise and wasabi paste is practically carb-free and supplies additional fat. Compared with breaded fish and fries (60 to 80 g of carbs per serving), this recipe cuts more than 95 % of the carbs while delivering significantly more protein and a healthier fat profile.
Source: FDDB Nutrition Database, fresh tuna , NIH Office of Dietary Supplements, Omega-3 Fatty Acids
Omega-3 fatty acids and keto
Tuna is one of the best natural sources of omega-3 fatty acids. One serving (200 g) provides around 1.5 to 2 g of EPA and DHA. On a ketogenic diet, which is already high in fat, eating fatty fish regularly improves the omega-6 to omega-3 ratio, a balance that is often out of whack on a typical Western diet.
Sesame, small seeds with plenty of fat
Sesame contains around 50 g of fat per 100 g, mostly unsaturated fatty acids. 2 tbsp (approx. 18 g) provides about 9 g of fat with only 0.4 g of net carbs. Sesame also contributes calcium, magnesium and iron, minerals that can sometimes fall short on a ketogenic diet.
How do I serve and vary the tuna steak?
Slice the steak and arrange it in a fan shape on the plate, placing the wasabi mayo and soy sauce in small bowls alongside. From my own experience, I recommend slicing and serving the tuna steak right after searing, if you wait too long the residual heat will continue to cook the center and it will lose its desired pink color.
Meal prep and taking it to go
Tuna steak also tastes excellent cold, much like sashimi. Chilled, it keeps for one day in the fridge at most. For work: sear the steak the evening before, slice it and take it along cold with wasabi mayo and a small side salad. Do not reheat in the microwave, it will ruin the texture.
Variation without tuna
Fresh salmon fillet (sushi grade) works as a direct swap, it has more fat (approx. 13 g per 100 g) and less protein but stays fully keto-friendly. Swordfish is another option with firmer flesh. For a vegetarian variation, thick slices of firm tofu work well, pressed and dried before being coated in sesame.
Which tips help with the keto tuna steak?
- Take the tuna steak out of the fridge at least 15 minutes before searing, at room temperature the crust browns more evenly without overcooking the center.
- Mix the sesame seeds on a flat plate and press the steak into them firmly on all sides, the crust holds better than if you sprinkle them on.
- Heat the pan on the highest setting and add the sesame oil only when the pan is smoking, this makes the sesame seeds turn crisp instantly.
- Sear for no more than 60 to 90 seconds per side, the center should stay raw to pink, like sashimi.
- Use soy sauce sparingly: 1 tbsp is enough as a dip, too much overpowers the delicate flavor of the tuna.
Nutrition values
| Nutrient | Per 100 g | Per serving | Keto rating |
|---|---|---|---|
| Calories | approx. 170 kcal | approx. 430 kcal | Moderate calorie density; energy comes mostly from protein (tuna) and fat (sesame, sesame oil, mayo). |
| Moderate calorie density; energy comes mostly from protein (tuna) and fat (sesame, sesame oil, mayo). | |||
| Fat | approx. 11 g | approx. 28 g | Healthy fat profile with a high share of unsaturated fatty acids from sesame and omega-3 from tuna. |
| Healthy fat profile with a high share of unsaturated fatty acids from sesame and omega-3 from tuna. | |||
| Net carbs | approx. 0.8 g | approx. 2 g | Minimal; comes almost entirely from sesame and soy sauce, ideal for strict keto days. |
| Minimal; comes almost entirely from sesame and soy sauce, ideal for strict keto days. | |||
| Sugar | approx. 0.3 g | approx. 0.7 g | Negligible; no added sugar in any of the ingredients. |
| Negligible; no added sugar in any of the ingredients. | |||
| Protein | approx. 16.5 g | approx. 42 g | Very high; tuna is one of the most protein-rich fish and provides all essential amino acids. |
| Very high; tuna is one of the most protein-rich fish and provides all essential amino acids. | |||
| Salt | approx. 0.4 g | approx. 1.0 g | Mostly from soy sauce; if you prefer less salt, use a reduced-sodium soy sauce (tamari). |
| Mostly from soy sauce; if you prefer less salt, use a reduced-sodium soy sauce (tamari). | |||
Note: Nutrition values are estimated averages per 100 g and per serving and may vary depending on ingredients, brands, portion size, and preparation. They do not replace individual nutrition or medical advice.
FAQ
Is tuna suitable for keto?
Yes, tuna has zero carbs, plenty of protein and valuable omega-3 fatty acids. It is one of the best fish for a ketogenic diet. Sushi-grade quality is important since the center of the steak stays raw.
Can I use canned tuna instead?
No, this recipe needs a fresh tuna steak (sushi grade). Canned tuna is already fully cooked and has a completely different texture, the sesame crust with a raw center only works with a fresh steak.
Does this recipe fit keto weight loss?
Very well: 42 g of protein at only 430 kcal and 2 g of net carbs make this dish one of the most efficient keto dinners around. If you want to cut calories further, leave out the mayonnaise, that saves about 70 kcal at the same protein level.
How do I spot fresh sushi-grade tuna?
Fresh tuna should be dark red to reddish brown, not brownish or gray. It smells like the sea, not fishy. At the fish counter, explicitly ask for sashimi or sushi grade, that means the fish has been frozen to kill parasites and is safe to eat raw.