The Ratios, Restated — Volek and Phinney's Starting Line
The why of LCHF and ketogenic eating was the subject of nutrition-001. This piece is about the what. The starting line is the macro framework exercise physiologist Jeff Volek and physician Stephen Phinney laid out in The Art and Science of Low Carbohydrate Living (2011):
- Strict ketogenic: 5–10% carbohydrate (usually under 50 g/day, under 20 g for deep ketosis), 70–75% fat, 20–25% protein.
- Modified Atkins: under 20 g of net carbs, with protein and fat relatively open.
- Liberal low-carb: 50–100 g carbs/day. Ketosis is shallow but insulin, triglycerides, and weight still improve for many.
A word on 'net carbs' — total carbohydrate minus fiber and most sugar alcohols — which dominates keto product labels. The US FDA does not formally endorse the term, and some sugar alcohols (maltitol in particular) raise blood glucose meaningfully. Treat labels as marketing.
What You Can Eat — Five Real-Food Groups
Over 70% of calories from fat doesn't mean 'any fat will do.'
Fats. Extra-virgin olive oil, avocado (about 2 g net carbs per half fruit), butter and ghee, coconut oil and its refined form MCT oil (C8/caprylic-heavy products convert to ketones fastest). Industrial seed oils — sunflower, corn, soy — are commonly minimized by clinicians on oxidation and inflammation grounds.
Animal protein. Eggs (since Whitaker 1996, meta-analyses in healthy adults have repeatedly failed to find a meaningful association between egg intake and cardiovascular mortality — familial hypercholesterolemia is the exception), fatty fish (salmon, mackerel, sardines), grass-fed beef, chicken thighs, and the Korean staples samgyeopsal and hangjeongsal. Processed meats are allowed but watch nitrates and sodium.
Low-carb vegetables. Leafy greens (spinach, romaine, kale), cruciferous (broccoli, cauliflower, cabbage), zucchini, asparagus, peppers, cucumbers, mung-bean sprouts. Korea's namul tradition is unexpectedly keto-friendly — provided no sugar, corn syrup, or maesil-cheong sneaks into the dressing.
Nuts and seeds. Macadamia (lowest carb), pecans, walnuts, almonds, hazelnuts, chia, flax, sunflower. Cashews are borderline. Korea's 'small pouch of mixed nuts' snack trend fits keto well — but honey-butter variants do not.
Dairy (if tolerated) and berries. Hard cheeses, heavy cream, unsweetened full-fat Greek yogurt, butter. Lactose intolerance is common in Korean adults — test your own response. Berries in palmfuls: a quarter-cup of blueberries, five or six strawberries.
What to Avoid — In One Line: Rice, Bread, Noodles, Sugar
All grains (rice, mixed grains, bread, noodles, pasta, oats, cereal). Starchy vegetables (potato, sweet potato, corn, lotus root, large quantities of carrot). All added sugars (table sugar, honey, syrup, agave, fruit juice). Most fruits (banana, mango, grapes, persimmon, peach). Legumes are debated — excluded on strict keto, allowed in moderation on liberal low-carb.
The biggest blind spot is the supermarket 'keto snack' aisle. Many low-carb breads, cookies, and chocolates lean on glycemic sugar alcohols like maltitol and isomalt, or refined seed oils. 'Low carb' is not a synonym for 'healthy.'
The Keto Food Card at a Glance
| Group | Eat | Avoid | Korean examples |
|---|---|---|---|
| Fats | Olive oil, avocado, butter, ghee, MCT, coconut oil | Refined seed oils, trans fats, margarine | Perilla/sesame oil OK (don't overheat); cut back on soybean frying oil |
| Protein | Eggs, salmon, mackerel, beef, pork, chicken thigh, shrimp, squid | Processed ham, sugar-glazed marinated meats, breaded fish | Samgyeopsal, gyeran-jjim OK / yangnyeom-galbi, donkkaseu, eomuk X |
| Vegetables | Spinach, lettuce, broccoli, cauliflower, zucchini, sprouts | Potato, sweet potato, corn, large amounts of carrot, sweet pumpkin | Sigeumchi/kongnamul namul, seaweed OK (no sugar) |
| Nuts/seeds | Macadamia, pecan, walnut, almond, chia, flax | Cashew (large), honey-butter nuts, sugar-coated | Plain mixed nuts / 'honey butter' line X |
| Fruit/sugar | Blueberry, strawberry, raspberry (small), avocado, lime | Banana, grape, mango, persimmon, honey, corn syrup, juice | A few berries / sikhye, sujeonggwa, fruit cheong X |
| Dairy | Hard cheese, heavy cream, unsweetened Greek yogurt, butter | Sweetened yogurt, condensed milk, ice cream, large milk volumes | Cheese slice / minimize processed cheese slices |
| Drinks | Water, black coffee, tea, sparkling water, bone broth | Soda, juice, sports drinks, sweetened lattes | Bone broth, miyeokguk OK (no sugar) / sikhye, plum tea, cola X |
The Real Trap in Korean Cuisine — Hidden Carbs in the Sauce
Korean food's collision with keto is not just rice. It's the sauce.
- Gochujang: typically 14–25% sugars (rice and corn syrup). Roughly 7–10 g net carbs per tablespoon.
- Soy sauce: low-carb itself, but commercial 'flavored' or 'simmering' soy sauces commonly add sugar. Read labels.
- Mulyeot, oligo-saccharide, maesil-cheong: the heart of Korean sweetness. They show up in nearly every braise, stir-fry, and seasoned vegetable.
- Tteokbokki sauce, bulgogi marinade, galbi marinade: more than half sugar. Off the table on keto.
Practical tip: home-made namul without sugar, syrup, or maesil-cheong — just sesame or perilla oil, garlic, chili powder, salt — is keto-compatible. Eating out, treat anything with 'yangnyeom' on the menu as suspect.
A Korean Keto Restaurant Manual
There are quite a few Korean dishes that are already close to keto.
- Samgyeopsal and Korean barbecue: drop the rice and the cold-noodle finisher and it's a near-perfect keto meal. Lettuce-perilla ssam, garlic, kimchi, and salt-with-sesame-oil dip instead of sweetened ssamjang. The most accessible keto eat-out in Korea.
- Sashimi and raw fish: nearly 100% protein and fat. Watch the chojang sauce and spicy soup base.
- Miyeokguk, kongnamul-guk, sirae-doenjang-guk: fine as long as no sugar sneaks in. Some restaurants do sweeten miyeokguk — ask once.
- Gyeran-jjim, dubu-kimchi, sugar-free dubu-jorim: among the safer banchan-room and Korean set-meal options.
- Mandu (dumplings): the wrapper is flour. 'Filling only' is rarely practical at a restaurant — cleanest to skip.
- Soup-with-rice, jook, noodles, tteokbokki, gimbap: all excluded.
Lee Hyeong-woo's 2018 The Ketogenic Diet is a frequently cited Korean-language practical manual for 'eating Korean without rice.' Treat it as a recipe reference rather than a clinical guideline — some of its broader medical claims go beyond the current evidence base discussed here.
Keto Flu and the Common Traps
Weeks one and two often bring headache, fatigue, muscle cramps, irritability, and mental fog — the so-called keto flu. Phinney's clinical notes consistently identify the cause as electrolyte loss: as insulin falls, the kidneys excrete more sodium.
- Sodium: add 3–5 g per day (1.5–2 tsp salt). Bone broth, miyeokguk, salted nuts are easy Korean vehicles.
- Potassium: spinach, avocado, salmon, mushrooms.
- Magnesium: pumpkin seeds, spinach, almonds, or a 200–400 mg supplement.
Other common traps:
- Too much protein. Some claim excess protein breaks ketosis via gluconeogenesis. Manninen 2004 and others argue gluconeogenesis is demand-driven and protein doesn't linearly evict ketosis. Translation: don't fear protein, but don't binge it.
- Low fiber → constipation. Up the leafy greens, chia, and flax.
- Micronutrient gaps. Long-term keto warrants periodic checks of vitamin C, B-complex, selenium, and calcium.
- Hidden restaurant carbs. See the sauce section above.
Measuring Ketones, and the Adaptation Window
Reaching ketosis usually takes two to four weeks (Volek and Phinney).
- Urine ketone strips: cheap, useful for the first one to two weeks. As adaptation progresses, ketones stay in the blood, so strips produce false negatives.
- Blood ketone meters: most accurate. 0.5–3.0 mmol/L defines 'nutritional ketosis.' Strips are expensive — daily testing is costly.
- Breath acetone devices (Ketonix, etc.): non-invasive, one-time cost. Less precise than blood.
Don't obsess over the number. Weight, waist circumference, fasting glucose, and the triglyceride-to-HDL ratio are more meaningful long-term markers.
Safety — Who Should Not Do Keto
Even evidence-based diets are not universal.
- Type 1 diabetes. Unsupervised keto risks diabetic ketoacidosis without insulin adjustment. Do it only with an endocrinologist.
- Pregnancy and lactation. Safety data are limited; the default is don't.
- History of eating disorders. Strict 'allowed/forbidden' rules can retrigger disordered patterns.
- Post-cholecystectomy or gallbladder dysfunction. Difficulty digesting large fat loads; MCT-leaning diets are kinder.
- Certain medications. SGLT-2 inhibitors (increased ketoacidosis risk), some anticonvulsants and diuretics need dose review.
- Long-term LDL concerns. Banach 2019 and similar reviews note that low-carb diets reliably improve weight, triglycerides, and HDL short-term, but a subset of responders sees marked LDL elevation, and the long-term cardiovascular consequences are not settled. Familial hypercholesterolemia and existing cardiovascular disease patients should keep up regular lipid panels.
Conclusion — Substitution, Not Subtraction
Keto framed as 'what I cannot eat' rarely lasts. Frame it as 'rice → cauliflower rice,' 'tteokbokki → dubu-kimchi,' 'fruit juice → a palmful of berries.' Eating out in Korea is undeniably harder. But samgyeopsal, miyeokguk, gyeran-jjim, and unsweetened namul are already nearly keto. This guide is a translation layer for the dinner table — if you've already read the science in nutrition-001, this is the version that goes into the shopping cart.
