Insulin resistance diet: Mediterranean vs low-carb vs keto — what actually works?

"Which diet should I choose for insulin resistance?" is one of the most common questions in my consultations. The Mediterranean, low-carb and ketogenic approaches all have solid evidence, but their mechanisms and long-term fit differ. Here is what the research says about who benefits from what.

Why the diet choice depends on the stage of insulin resistance

Insulin resistance is not a binary diagnosis — it is a spectrum from mild compensatory hyperinsulinaemia to established type-2 diabetes. HOMA-IR 1.2 requires a different intervention than HOMA-IR 4.5. That is why there is no single "best" diet — there is a best diet for a specific person at a specific metabolic stage.

Mediterranean diet: widest evidence base and best long-term adherence

PREDIMED (Estruch, NEJM 2018) showed a 30% reduction in cardiovascular events, and a sub-analysis (Salas-Salvadó, Diabetes Care 2011) a 52% lower incidence of type-2 diabetes. Mechanism: high polyphenol intake (olive oil, berries, fish), omega-3, high fiber, low ultra-processed food share.

• Carbs ~40–45% of energy, mostly legumes and whole grains
• Olive oil as primary fat (35–40% of energy), nuts, fatty fish 2–3× per week
• Red meat < 1–2× per week, poultry and eggs in moderation
• Easiest to sustain long-term — socially and culturally flexible

Low-carb diet: the best compromise

DIETFITS (Gardner, JAMA 2018) compared low-carb and low-fat diets — 12-month weight loss was comparable, but insulin sensitivity improved more in the low-carb group. Carbs at 20–35% of energy (~80–150 g/day), the body does not enter ketosis, but insulin load drops significantly.

• Carbs primarily from vegetables, berries, legumes
• Does not require the strictness of ketosis — socially flexible
• Fits most people with HOMA-IR between 1.5 and 3.5
• Metabolic flexibility is preserved — the body can use both glucose and fat

Ketogenic diet: strongest effect in more severe cases

Virta Health (Hallberg 2018; Athinarayanan 2019 — 2 years) reported 60% remission of type-2 diabetes, HbA1c dropping from 7.6 to 6.3%, and medication withdrawal in 57% of patients. Carbs < 20–50 g/day, the body enters ketosis, and average daily insulin drops dramatically.

• Indications: HOMA-IR > 3.5, established type-2 diabetes, MASLD, PCOS with IR
• Requires an adaptation phase (2–4 weeks) and electrolyte support (sodium, magnesium, potassium)
• Not for everyone — see the "What is keto" article for contraindications
• Long-term adherence is harder than with the Mediterranean pattern

Clinical comparison: what fits whom?

• Prevention + mild IR (HOMA-IR 1.0–1.9): Mediterranean
• Moderate IR (HOMA-IR 2.0–3.5), overweight, prediabetes: low-carb Mediterranean hybrid
• Established T2D, MASLD, treatment-resistant IR: therapeutic keto under supervision for 3–6 months, then transition to low-carb Mediterranean
• PCOS + IR: low-carb Mediterranean or cyclical keto, depending on the clinical picture

"The best diet for insulin resistance is the one that lowers your insulin load enough and that you can sustain for years, not months."

Common principles that apply to all three

• Eating window 10–12 h — all three approaches are significantly more effective when the last meal is at least 3 h before bed
• Cut ultra-processed foods — regardless of carbohydrate percentage
• Protein 1.2–1.6 g/kg body weight — preserves muscle mass, the largest insulin-sensitive tissue
• Daily movement + resistance training 2–3× per week — outperforms diet alone in combination

Clinical bottom line

Mediterranean is the best choice for prevention and mild IR — its evidence base and long-term adherence are unmatched. Low-carb is the best compromise for most patients with IR. Keto is a therapeutic tool for severe metabolic states, not a lifestyle for everyone. The choice should be based on your metabolic markers, not on a trend.