How Martha McKittrick Uses Nutrition to Manage PCOS

Who Is Martha McKittrick and Why Does Her PCOS Work Matter?

Martha McKittrick is a New York-based registered dietitian with a master's degree in clinical nutrition and a Certified Diabetes Educator credential. She has spent more than two decades working specifically with women who have polycystic ovary syndrome, insulin resistance, and related metabolic conditions. Her clinical practice, City Dietitian, and her long-running online presence have made her one of the most-cited non-physician voices in the PCOS nutrition space.

Allara Health, founded in 2020, built its virtual PCOS clinic model around the idea that coordinated care between physicians, nurse practitioners, and registered dietitians produces better outcomes than prescriptions alone. McKittrick's framework maps directly onto that model. Her dietary recommendations are not generic "eat healthy" guidance. They are condition-specific protocols tied to the three dominant metabolic drivers of PCOS: hyperinsulinemia, chronic low-grade inflammation, and androgen excess.

Why Dietitians Are Central to PCOS Care

The 2018 International Evidence-Based Guideline for the Assessment and Management of PCOS, developed by the Monash University-led consortium and endorsed by the Endocrine Society, explicitly states that lifestyle intervention including dietary modification is first-line therapy for most women with PCOS before pharmacological options are introduced [1]. That guideline position gives dietitians like McKittrick a formal clinical role, not a supplementary one.

The Allara Health Clinical Model

Allara pairs each patient with a physician and a dietitian who share a single care record. McKittrick's nutrition protocol integrates into that record so medication decisions (such as initiating metformin 500 to 2,000 mg/day or a combined oral contraceptive) are made with full visibility into dietary progress. The result is a feedback loop that most conventional practices do not offer.

The Metabolic Case for a PCOS-Specific Diet

PCOS is not a single-phenotype condition. The Rotterdam criteria require two of three features: oligo-ovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound [2]. That diagnostic breadth means women in McKittrick's practice arrive with very different metabolic profiles. Her starting point is always a metabolic assessment, not a generic meal plan.

Insulin Resistance as the Nutritional Target

Between 50% and 70% of women with PCOS show insulin resistance on euglycemic-hyperinsulinemic clamp testing, and this occurs across all BMI categories [3]. Elevated insulin drives the ovarian theca cells to produce excess testosterone. Lowering the post-meal insulin response is therefore a direct hormonal intervention, not just a weight-loss strategy.

McKittrick's core tool for this is the glycemic index (GI). A 2012 randomized controlled trial published in the American Journal of Clinical Nutrition (N=96) found that a low-GI diet produced greater improvements in insulin sensitivity and menstrual cyclicity over 12 months compared with a conventional healthy diet in women with PCOS [4]. That trial is one of the most-cited pieces of evidence she references in both her practice and her online educational content.

Inflammation as the Second Driver

C-reactive protein and interleukin-6 are measurably elevated in PCOS even after controlling for BMI [5]. Chronic low-grade inflammation worsens insulin signaling and contributes to endothelial dysfunction that raises long-term cardiovascular risk. McKittrick addresses inflammation through fat quality, not fat quantity. She emphasizes omega-3 fatty acids from fatty fish (two to three servings per week), walnuts, flaxseed, and extra-virgin olive oil, while reducing omega-6-heavy refined seed oils.

Androgen Excess and the Dietary Connection

A 2020 systematic review in Nutrients (N=14 studies) found that dietary patterns with a lower glycemic load were associated with statistically significant reductions in free testosterone and dehydroepiandrosterone sulfate (DHEAS) in women with PCOS [6]. Lowering androgen levels through diet has downstream effects on acne, hirsutism, and hair thinning, which are among the most psychologically distressing symptoms for many patients.

McKittrick's Core Nutrition Framework for PCOS

McKittrick's approach can be organized into five operating principles. Each one targets a specific metabolic pathway. They are designed to work together, but she applies them in order of a patient's readiness and current baseline.

Principle 1: Carbohydrate Quality Over Carbohydrate Quantity

McKittrick does not advocate a very-low-carbohydrate or ketogenic diet as a default for PCOS. Her position, consistent with the 2018 PCOS guideline, is that carbohydrate quality matters more than total grams. She targets approximately 40 to 45% of total calories from carbohydrates, with the emphasis on foods that score below 55 on the glycemic index scale.

Preferred sources include:

• Steel-cut or rolled oats (GI 55) rather than instant oats (GI 79)
• Legumes: lentils (GI 29), chickpeas (GI 28), black beans (GI 30)
• Non-starchy vegetables with every meal
• Berries over tropical fruits for lower fructose load
• Whole-grain sourdough (GI approximately 54) over white bread (GI 75)

She avoids demonizing any single food but uses the concept of "pairing," meaning she rarely recommends eating a carbohydrate alone. Pairing a carbohydrate with protein, fat, or fiber slows gastric emptying and blunts the insulin response. This is basic physiology, but its clinical application is specific.

Principle 2: Protein at Every Meal

McKittrick recommends 25 to 30% of total calories from protein, distributed across three meals. For a woman consuming 1,800 kcal/day, that translates to roughly 112 to 135 g of protein daily. Protein raises satiety hormones including peptide YY and GLP-1 (the same pathway targeted by semaglutide), which helps regulate appetite without medication in some patients.

Preferred sources she highlights:

• Eggs (a complete protein with no carbohydrate load)
• Greek yogurt (17 g protein per 170 g serving)
• Salmon and sardines (doubling as omega-3 sources)
• Edamame and tofu for patients preferring plant-based patterns
• Chicken breast, turkey, and lean cuts of beef

She cautions against high-fat processed meats as a protein strategy because their saturated fat content may worsen the inflammatory profile already present in PCOS.

Principle 3: Anti-Inflammatory Fat Selection

Total fat intake in McKittrick's framework sits around 30 to 35% of calories, but the type of fat is the variable she adjusts most aggressively. She pushes patients toward a Mediterranean-leaning fat profile.

The 2019 PREDIMED-Plus trial (N=7,447) demonstrated that a high-polyphenol extra-virgin olive oil intake, as part of a Mediterranean dietary pattern, reduced inflammatory markers by 8 to 12% over 12 months compared with a low-fat control diet [7]. While PREDIMED-Plus was not a PCOS-specific trial, its inflammatory biomarker data are directly relevant to the inflammatory pathway McKittrick targets.

Specific fat guidance:

• Extra-virgin olive oil as the primary cooking fat (2 to 3 tablespoons per day)
• Fatty fish two to three times per week for EPA and DHA
• Avocado as a source of monounsaturated fat and fiber together
• Limiting butter and coconut oil, which raise LDL in insulin-resistant patients

Principle 4: Fiber as a Non-Negotiable

McKittrick targets a minimum of 25 to 30 g of dietary fiber per day for all her PCOS patients. Both soluble and insoluble fiber matter. Soluble fiber (oats, legumes, psyllium) directly reduces the rate of glucose absorption and feeds short-chain fatty acid-producing gut bacteria that may improve insulin sensitivity. Insoluble fiber (vegetables, whole grains) supports gut transit and reduces estrogen recirculation via the enterohepatic pathway, which can be relevant in the androgen-dominant PCOS phenotype.

A 2019 study in Clinical Endocrinology (N=72) found that increasing dietary fiber by 10 g/day over 12 weeks reduced fasting insulin by 12.5% and improved HOMA-IR scores in women with PCOS [8].

Principle 5: Meal Timing and Frequency

McKittrick's position on meal timing is practical. She recommends three structured meals per day with no more than five hours between them. This prevents the sharp drop in blood glucose that drives carbohydrate cravings and leads to portion-uncontrolled eating in insulin-resistant patients.

She is not dogmatic about intermittent fasting. A 2023 study in the Journal of Clinical Endocrinology and Metabolism (N=60) found that time-restricted eating over 12 weeks reduced androgen levels and improved insulin sensitivity in women with PCOS, but adherence at six months was significantly lower than in the three-meal-per-day group [9]. McKittrick's clinical read on this data is that a pattern a patient will actually follow for years outperforms a metabolically superior pattern that gets abandoned in four months.

Specific Foods McKittrick Highlights for PCOS

Beyond principles, McKittrick is specific about foods. This specificity is one reason her content resonates with patients who have received generic dietary advice and found it unhelpful.

Inositol-Rich Foods

Myo-inositol is found in high concentrations in legumes, citrus fruit, whole grains, and nuts. A 2016 randomized controlled trial in the International Journal of Endocrinology (N=120) found that supplementing with 4 g/day of myo-inositol over six months improved ovulation rate from 15% to 65% and reduced fasting insulin by 23% compared with placebo [10]. McKittrick emphasizes food sources of inositol as a complement to (not a replacement for) supplemental forms when appropriate.

Magnesium-Dense Foods

Magnesium deficiency is common in PCOS and correlates with insulin resistance severity. Pumpkin seeds (156 mg per ounce), dark leafy greens, almonds, and dark chocolate (70%+) appear regularly in her patient meal guides. The 2013 Diabetes Care meta-analysis (N=536,318 participants) found that every 100 mg/day increase in dietary magnesium was associated with a 15% lower risk of developing type 2 diabetes, the condition PCOS patients are at highest risk for over their lifetimes [11].

Foods McKittrick Restricts or Eliminates

She does not issue blanket prohibitions. The foods she recommends reducing or removing are:

• Sugar-sweetened beverages (direct insulin spiker with no nutritional offset)
• Ultra-processed snack foods high in refined flour and industrial seed oils
• Alcohol, particularly wine and cocktails, which raise cortisol and estrogen and provide pure caloric load with no micronutrient return
• Dairy in large quantities for patients with acne-predominant PCOS, where the insulin-like growth factor-1 (IGF-1) content of milk may worsen androgen-driven skin symptoms

How McKittrick Addresses Weight in PCOS Without Making It the Sole Focus

PCOS and weight are entangled in a way that frustrates many patients. Hyperinsulinemia promotes fat storage, particularly visceral fat, which then worsens insulin resistance in a self-reinforcing cycle. Losing weight improves the condition, but the condition itself makes weight loss harder than it would be in a metabolically healthy person.

McKittrick's clinical position, consistent with the 2018 PCOS guideline's explicit recommendation, is that even modest weight reduction of 5 to 10% of body weight restores ovulatory function in many anovulatory women with PCOS [1]. The guideline notes this benefit appears independent of the specific dietary pattern used, which means adherence to any good-quality pattern outweighs the theoretical superiority of any single diet.

For patients with BMI above 30 who have not achieved sufficient metabolic improvement through diet and lifestyle alone, the 2018 guideline and the American Association of Clinical Endocrinology 2022 Obesity guidelines support pharmacological adjuncts including metformin, and in selected patients, GLP-1 receptor agonists such as liraglutide 3.0 mg or semaglutide 2.4 mg [12]. McKittrick's nutrition protocol is designed to run alongside these medications, not be replaced by them.

What McKittrick Says About Supplements in PCOS

Supplements are a contested area in PCOS care. McKittrick's framework is food-first, but she acknowledges that several supplements have enough evidence to discuss with a clinician.

Inositol

The best-studied supplement for PCOS. The combination of myo-inositol and D-chiro-inositol at a 40:1 ratio (the physiological plasma ratio) at doses of 2 to 4 g/day has been shown in multiple RCTs to improve ovulation rate, reduce fasting insulin, and lower testosterone [10]. McKittrick recommends patients bring this evidence to their Allara physician rather than self-prescribing.

Vitamin D

Vitamin D deficiency is present in 67 to 85% of women with PCOS in studies using a threshold of 20 ng/mL [13]. Repletion to above 30 ng/mL with cholecalciferol 1,000 to 4,000 IU/day has been associated with improvements in AMH levels and menstrual regularity in observational data, though RCT evidence remains limited.

Omega-3 Fatty Acids

When dietary fish intake is insufficient, McKittrick supports supplementing with 2 to 4 g/day of combined EPA and DHA. A 2018 meta-analysis in Reproductive Biology and Endocrinology (N=six RCTs) found omega-3 supplementation at this dose range reduced testosterone by a mean of 0.5 nmol/L and improved menstrual regularity compared with placebo [14].

What She Does Not Recommend

Berberine is frequently promoted on social media as a "natural metformin." The evidence in PCOS is preliminary and the safety profile at commonly promoted doses (1,500 mg/day) is not established in long-term trials. McKittrick advises caution and physician supervision before use.

Working With Allara Health: What the Process Looks Like

A patient engaging with McKittrick's approach through Allara Health typically moves through a structured sequence. The initial intake includes a full hormonal panel (LH, FSH, AMH, total and free testosterone, DHEAS, fasting insulin, HbA1c, lipid panel, thyroid function) and a dietary intake assessment. The dietitian then builds a specific macro and food-quality target, not a printed meal plan, based on that patient's phenotype, food preferences, and current eating patterns.

Follow-up with the dietitian occurs every two to four weeks in the first three months. Lab work is repeated at three months. Adjustments to the nutritional approach are made based on objective changes in fasting insulin, HOMA-IR, and menstrual cycle data logged in the platform.

The Endocrine Society's 2023 Clinical Practice Guideline on PCOS states: "Lifestyle modification including dietary changes and increased physical activity is recommended as first-line management for all women with PCOS" [15]. That recommendation positions the dietitian as a front-line clinician, which is exactly the role McKittrick fills within the Allara model.

Physical Activity as McKittrick's Nutritional Partner

McKittrick does not separate nutrition from movement in her clinical framework. She recommends 150 minutes per week of moderate-intensity aerobic activity (consistent with American Heart Association guidelines) combined with two to three sessions per week of resistance training [16].

Resistance training deserves specific mention in PCOS. Skeletal muscle is the body's largest insulin-sensitive tissue. Building and maintaining muscle mass increases the volume of tissue that can clear glucose from the bloodstream without requiring high insulin output. A 2020 RCT in the Journal of Clinical Medicine (N=45) found that 12 weeks of resistance training in women with PCOS reduced fasting insulin by 19.2% and HOMA-IR by 20.4% without dietary change [17].

McKittrick recommends timing the largest carbohydrate-containing meal within two hours of resistance training sessions to take advantage of the post-exercise window of enhanced insulin sensitivity.