Dr. Dante Ruskin, diabetologist & intensivist Dr. Dante Ruskin Diabetes & Critical Care Specialist
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Is Anchovy (Nethili / Kozhuva) Good for Diabetes?

YES

Yes — anchovy is one of the better fish on this coast for diabetes. Nethili carries no carbohydrate at all, so the fish itself barely moves a blood sugar reading, and because it is eaten whole with its bones it delivers calcium that a filleted fish cannot. The batter and the reused oil are the problem, not the nethili.

Answered by Dr. Dante Ruskin · Diabetologist & Intensivist

So judge the cooking, not the fish. Nethili in a kuzhambu, or boiled the avicha-meen way, is a clean protein plate. The evening roadside fry — rice flour, maida, chilli, oil that has been working since morning — is a fried snack that happens to contain fish. Same nethili, two very different verdicts.

Why nethili earns a yes

Anchovy is the small silver fish this coast lands in shoals — Stolephorus, the whitebait that CMFRI’s district survey found dominating the catch on the western side, from Cape Comorin up past Colachel and Thengapattanam to Neerodi, which is the Marthandam catchment. On a plate it is close to pure protein and fat. USDA’s profile for raw anchovy gives about 131 kcal, 20 g of protein and zero carbohydrate per 100 g. Nothing on that list raises blood glucose the way a mound of rice does. And because nethili is eaten whole — head, spine and all — it supplies calcium that a filleted fish cannot: roughly 147 mg per 100 g, against a trace in a boneless steak cut from a large fish. For a patient who cannot afford a daily fruit or a supplement, that is a cheap, real advantage sold in every market from Vadasery to Kaliakkavilai.

The batter, the oil, and what arrives beside it

Then we cook it. The evening nethili varuval at a roadside stall is dipped in rice flour and maida with chilli and salt, then dropped into oil that has been frying since morning. The fish stays zero-carb; the coating does not, and reusing deep-frying oil is exactly what ICMR-NIN’s 2024 dietary guidelines tell Indians to stop doing. The larger problem is the company the plate keeps. Nethili fry rarely arrives alone — it comes beside parotta, or as the side to a second helping of rice, or with sweet tea at four in the afternoon. Measure the meal rather than the fish and the fried plate stops looking innocent, while the fish itself remains exactly as blameless as it was.

Nethili the way Nanjil kitchens already cook it

The better forms are not imported advice; they are local. Nethili kuzhambu — ground coconut, tamarind, sometimes raw mango or drumstick, finished with coconut oil — puts the fish in gravy instead of batter. On the Kerala-border side the same curry takes kudampuli and coconut milk. Better still is avicha meen, the district’s boiled-fish signature: fish cooked with coconut paste and tamarind and no added oil at all, which is about as close to a diabetologist’s ideal fish preparation as any tradition has arrived at without being asked. Go easy on the coconut milk if your cholesterol is high, and watch what sits beside the curry — the rice is the carbohydrate on that plate, not the nethili. If it is kappa instead of rice, tapioca has its own answer.

Nethili karuvadu — same fish, a different problem

Dried anchovy is a district product in its own right: “Kanyakumari special” nethili karuvadu is sold branded, and Colachel and Kadiapattinam are the dry-fish trade points. Along this border belt, most households eat dried fish once or twice a week. For blood sugar, karuvadu is as harmless as fresh nethili — still no carbohydrate anywhere in it. What it carries instead is salt, and a great deal of it: heavily salted anchovy products run into thousands of milligrams of sodium per 100 g (USDA lists canned anchovy in oil at about 3,668 mg), and home-salted karuvadu belongs in the same conversation. If you carry high blood pressure or kidney disease alongside diabetes — and many people in this clinic carry at least the first — make karuvadu kuzhambu a weekly dish, soak the fish before cooking, and add no further salt to the gravy. That is the same argument as the one on the stroke-prevention page, and dried fish has a page of its own.

What I actually tell patients in the clinic

Eat nethili. Eat it two or three times a week if you like it — it is cheap, it is landed here rather than trucked in, and it is a protein that displaces something heavier from the plate. Keep it in kuzhambu or boiled. Keep the fried version to an occasional evening rather than a standing habit, and when you do have it, ask for fresh oil and leave the parotta alone. If your two-hour reading after a nethili meal comes back high, look at the rice first — that is where the number came from. And bring the actual week to your review, not the ideal one: how many fried evenings, how much karuvadu, how much rice. That conversation changes an HbA1c more reliably than dropping a fish nobody needed to drop. Fry versus curry is the whole of the difference.

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Frequently asked questions

The fish is fine; the coating and the oil are not. A rice-flour and maida batter adds refined carbohydrate to a food that had none, and roadside oil is usually reused all day — something ICMR-NIN's dietary guidelines tell Indians to avoid. Keep the fry occasional, ask for fresh oil, and do not pair it with parotta.

A palm-sized helping, roughly 100 g, is a sensible serving, and two or three fish meals a week suits most patients well. Nethili adds no carbohydrate, so the portion question is really about the rice beside it and the oil it was cooked in — both of which you control more easily than the fish.

For blood sugar, yes — dried anchovy carries no carbohydrate either. The catch is salt. Salted, sun-dried anchovy is very high in sodium, so if you also carry high blood pressure or kidney disease, treat karuvadu kuzhambu as a weekly dish rather than a daily one, soak the fish first, and add no further salt to the gravy.

Yes, and this is the quiet advantage of small fish. Because nethili is eaten head, bones and all, it supplies calcium a boneless steak of a large fish does not — USDA lists about 147 mg per 100 g of raw anchovy. That matters for older patients with diabetes, who tend to lose bone quietly.

For blood sugar the price of the fish makes no difference — seer, sardine and nethili all carry zero carbohydrate. Small fish do have two edges: they are eaten whole, so you get the bone calcium, and they sit low in the food chain, so the mercury caution that applies to shark and the big predators does not apply here.