The Return of Atkins — A 50-Year Debate
Low-carb high-fat (LCHF) was popularized when US cardiologist Robert Atkins published Dr. Atkins' New Diet Revolution in 1972. His thesis was simple: 'Obesity is caused by carbohydrates and insulin, not fat.' This clashed head-on with the prevailing US low-fat orthodoxy; the AMA called him 'dangerous.'
The 2002 revised edition became a bestseller, igniting the 21st-century LCHF revival. In 2011, Stephen Phinney and Jeff Volek codified the stricter form — ketogenic diet (<50g carbs/day, 70–80% fat) — in The Art and Science of Low Carbohydrate Living. In 2012, pediatric endocrinologist Robert Lustig argued in Fat Chance that fructose drives metabolic syndrome, while Boston Children's David Ludwig formalized the Carbohydrate-Insulin Model (CIM): refined carbs spike insulin, force fat storage, and weight gain is hormonal rather than 'overeating.'
Three Pivotal RCTs
LCHF earned scientific weight beyond fad-diet status through three trials.
Shai 2008 NEJM: 322 Israeli workers randomized to low-fat, Mediterranean, or low-carb for 2 years. Low-carb won marginally — 4.7kg lost (low-fat 2.9kg, Mediterranean 4.4kg). HDL and triglycerides also improved most on low-carb.
Hall 2017 Cell Metabolism: 17 subjects confined to an NIH metabolic ward with precisely controlled calories and varied macro ratios. The result was a blow: the promised 'metabolic advantage' did not appear. Differences in fat loss were trivial at matched calories; early keto even produced transient protein loss.
Gardner DIETFITS 2018 JAMA — the most decisive trial: Stanford's Christopher Gardner randomized 609 obese adults to 'healthy low-fat' vs 'healthy low-carb' for 12 months. Both groups emphasized whole foods (no refined sugar, no processed food), no calorie cap. Result: both lost ~5–6kg with no significant difference (low-fat −5.3kg, low-carb −6.0kg, p=0.07). Critically, pre-measured insulin secretion patterns and 3-SNP genotype did NOT predict which diet would work better — the strongest rebuke yet to strong CIM claims.
Macro Comparison
| Diet | Macro C/F/P | Key RCT | 1-yr loss | Adherence difficulty | Main risks |
|---|---|---|---|---|---|
| Ketogenic | 5/75/20 | Athinarayanan 2019 (T2D) | 5–7kg | Very high | Keto flu, LDL↑, kidney stones |
| LCHF (moderate) | 20/55/25 | Shai 2008, Gardner 2018 | 5–6kg | Medium-high | Sat fat↑, fiber↓ |
| Low-fat | 55/20/25 | DIETFITS, Look AHEAD | 4–5kg | Medium | Refined-carb trap, less satiety |
| Mediterranean | 45/35/20 | PREDIMED 2013 | 4–5kg | Low | Few (cost of olive oil, nuts) |
| Very-low-cal | 50/15/35 (~800kcal) | DiRECT Lean 2018 | 10–15kg (short) | Very high | Hard to maintain, needs supervision |
Diabetes Remission — Different Paths, Same Destination
LCHF draws special attention for type 2 diabetes. Roy Taylor's Lim 2011 Diabetologia (8-week 600kcal very-low-cal) showed T2D remission via pancreatic and liver fat loss; the follow-up DiRECT trial (Lean 2018 Lancet) achieved 46% T2D remission at 12 months — using total liquid meal replacement, not LCHF.
Meanwhile, Athinarayanan 2019's virtual-clinic study found >60% of keto-adherent patients normalized HbA1c and reduced medication at 2 years. The pattern: weight loss itself is the lever, and LCHF, very-low-cal, or bariatric surgery all reach the same destination. The real question is sustainability.
Risks and Controversy
Keto flu: Weeks 1–2 of keto, kidneys dump sodium fast, causing headache, fatigue, cramps. Salt and electrolytes help.
Long-term cardiovascular risk: Banach 2019 European Heart Journal (n=24,825 NHANES) observed the strictest low-carb tertile had 32% higher all-cause and 50% higher cardiovascular mortality. Observational, so causation is weak — but the WHO 2023 saturated-fat guidelines still recommend reduction, and LCHF often raises saturated fat.
Adherence: Anton 2017 review found that regardless of diet type, most regain ≥50% of lost weight by year 5. Hall 2019 concluded diet quality (whole vs ultra-processed) matters more than macro ratio. Much keto 'success' may be from cutting refined sugar and processed foods rather than the fat ratio per se.
Korea's Boom — From Defamation of Fat to Cafés
LCHF exploded in Korea after the September 2016 MBC documentary 지방의 누명 (The Defamation of Fat). 'Fat doesn't fatten you; carbs do' was a Copernican shift for Koreans who had followed 30 years of low-fat advice. A 2017 SBS Special amplified the trend; Naver 'low-carb high-fat cafés' exploded to tens-to-hundreds of thousands of members. Butter coffee, MCT oil, and avocado became health icons.
But in August 2017, five major societies — Korean Nutrition Society, Korean Society of Cardiology, Korean Diabetes Association and others — issued a joint statement warning of 'unproven long-term safety and inappropriateness for general recommendation.' They acknowledged Koreans' 65% carb share is high, but the fix was 'replace refined carbs with whole grains and vegetables,' not LCHF.
Adaptation to Korean meals is genuinely hard. Rice, soup, stew, noodles, gimbap, rice cake, fruit — all carb-centric. Take rice out of bibimbap and what remains? Eating out and corporate dinners make keto nearly impossible. Specialists like dietitian Lee Hyung-woo propose 'Korean keto' using tofu noodles, konjac rice, and meat wraps — but social meals are the weak point.
Conclusion: There Is No 'Best Diet'
Fifty years of evidence point one way. The best diet is the one that fits your body, is sustainable, and emphasizes whole foods. When LCHF works spectacularly for someone, the removal of refined carbs and processed food likely drives most of the effect. Mediterranean, DASH, or whole-food low-fat can deliver the same.
If you try LCHF: ① consult a physician and dietitian (especially with kidney/liver disease or medications), ② whole foods over 'keto junk,' ③ favor olive oil, nuts, fish over plain saturated fat, ④ check LDL, liver, kidney at 3 months, ⑤ flexibility for social Korean meals — a carb indulgence every week or two is fine. Diets are tools, not religions. The Defamation of Fat was a provocative challenge, but the weight of evidence answers not 'what to avoid' but 'what to eat often, and how.'
