Japanese food feels like it ought to be a keto dream. It is light, full of fish and vegetables, and a world away from heavy, floury cooking. Then you remember the rice. Sushi is built on it, and sushi rice is not just rice but rice with added sugar, which makes a plate of rolls one of the quieter carb traps out there. The good news is that Japanese cuisine has plenty that suits keto beautifully once you know what to order and what to leave.
The rice problem
Be clear-eyed about where the carbs are. A single maki roll cut into its six or eight pieces is largely rice, and a couple of rolls can put you well past 30 or 40g of carbohydrate before you have really started. Nigiri, those hand-pressed fingers of rice topped with fish, are the same story in miniature. The fish on top is not the issue; the cushion of sweetened white rice underneath it is. So the move is not to give up sushi restaurants, it is to change what you point at on the menu.
Sashimi is the cheat code
The simplest answer is sashimi: slices of raw fish served on their own, with no rice at all. It is essentially pure protein and healthy fats, close to zero carbs, and it is arguably the best of the fish anyway because nothing competes with it. Order a sashimi selection instead of rolls and you get all the salmon, tuna, mackerel and yellowtail you came for, minus the carb load. For most people this single swap solves the whole problem in one move.
The other dishes that work
Sashimi is not the only friend on the menu. Edamame, young soybeans in the pod, make a great low-carb starter. Miso soup is light and fine in normal amounts. Salt-grilled fish, such as the classic grilled mackerel or salmon, is excellent and naturally low-carb, as is most plainly grilled or skewered meat and fish, though see the sauce warning below. Hotpot dishes like shabu-shabu, where you cook thin slices of meat and vegetables in broth, are largely keto-friendly if you go easy on any sweet dipping sauce. And tofu itself, plainly served, is low-carb, even if some tofu dishes are battered.
If you want the sushi experience without the rice, ask for hand rolls with extra fish and less rice, or build a poke or chirashi-style bowl, all the fish and toppings piled over salad leaves or cauliflower rice rather than sticky rice. That works especially well at home, where you control the base entirely.
The sauces and hidden carbs
This is where Japanese food catches people out, because several of its signature flavours are sugar in disguise. Teriyaki is the main culprit, essentially a sweet glaze, so a teriyaki dish can carry as many carbs as a dessert. Eel sauce and other thick, glossy sweet sauces are the same. The sushi rice itself is sweetened, as mentioned. And anything described as tempura or katsu is coated in batter or breadcrumbs and fried, which puts it firmly in carb territory, however tasty. Noodle dishes, ramen, udon and soba, are also off the table for obvious reasons.
Soy sauce, by contrast, is low in carbohydrate and fine to use, though it is very high in salt, which is worth keeping in mind given how much keto already shifts your sodium and other electrolytes. Tamari is a gluten-free version if that matters to you. Wasabi is fine in the small amounts you would use, and while pickled ginger does contain a little sugar, a few slices will not hurt. The rule of thumb is simple: be suspicious of anything sweet, sticky, battered or breaded, and lean towards the clean, grilled and raw.
Ordering it in practice
Put together, a comfortable keto order looks something like this: edamame and miso soup to start, a generous sashimi selection as the centrepiece, perhaps some salt-grilled fish or a few skewers asked for without the sweet sauce, and a seaweed or cucumber salad on the side if you fancy it. Skip the rolls, the nigiri, the tempura, the katsu, the teriyaki and the noodles. You will eat very well, leave satisfied, and barely touch your carb budget, which is more than most cuisines allow when you are eating out, as the wider eating-out guide covers.
At home
Making it yourself is even easier, because you set the rules. Buy sashimi-grade fish and slice it, or build poke bowls with cubed raw fish, avocado, cucumber and a sprinkle of sesame over salad or cauliflower rice. A drizzle of soy, a little sesame oil, some spring onion and chilli, and you have a fresh, fast, almost carb-free meal that tastes like a treat. It is one of the nicer ways to eat low-carb at home with very little effort.
The bottom line
Sushi itself is a carb trap because of the sweetened rice, but Japanese food as a whole is one of the easier cuisines to do on keto. Order sashimi instead of rolls, lean on edamame, miso, grilled fish and hotpot, and steer clear of teriyaki, tempura, katsu and noodles. Watch the sweet sauces, enjoy the soy in moderation for the salt, and at home just build the bowl over salad or cauliflower rice. You keep almost all of what makes Japanese food a pleasure and lose the part that was working against you.
This is general information about the ketogenic diet, not medical advice. Keto does not suit everyone; if you are pregnant, on medication, or managing a condition such as diabetes, speak to a doctor or dietitian first. Raw fish is not suitable for everyone, including during pregnancy.