Keto Research Round-Up – May 2026

Clinical trials, reviews, and other types of research on keto diets are published continually as interest in this metabolic strategy grows. Here are some recent developments.

Keto for PCOS 

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. Insulin resistance is the main cause of this condition, so it makes sense that following a diet that improves insulin sensitivity—like a keto diet—may be helpful for restoring hormone balance and improving the symptoms that result from elevated insulin and testosterone, such as acne, oily skin, weight gain, and body hair growth. 

A meta-analysis published earlier this year looked at results from ten different studies of keto diets for women with PCOS. The researchers determined that keto led to significant decreases in body weight, waist circumference, triglycerides, and total cholesterol, plus improved insulin sensitivity and decreased luteinizing hormone (which is typically elevated in PCOS and contributes to menstrual cycle irregularity). They called keto “a promising dietary intervention” for weight loss and improving insulin sensitivity and reproductive hormone profiles in overweight women with PCOS.

(See this article to learn more about PCOS and how keto can help.)

Vegetarian Low-Carb Diet for Type 2 Diabetes

Looking at keto recipes on social media, you could easily get the impression that keto is nothing but steak and bacon with a side of steak and bacon … and a piece of salmon here and there for political correctness. But this simply isn’t the case. In fact, you don’t have to eat meat at all to be successful on a very-low-carb diet. An article published recently in Frontiers in Nutrition profiles an Indian man who achieved long-term remission of type 2 diabetes (T2D) through following a low-carb vegetarian diet.

The subject started by reducing carb intake to ~100g per day, then eventually shifted to a more ketogenic level (30g per day). After being strict keto for a few years, he returned to the moderate level of carb intake (100g per day) and currently maintains a normal (non-diabetic) HbA1c (a measurement of your blood sugar levels over the last 2-3 months) with no diabetes medications. Vegetarian and vegan keto can work because what matters most is keeping carbohydrate intake low—not whether the fat and protein come from plants or animals.

Beans and other vegetarian sources of protein may be too high in carbs for a strict keto diet, but eggs and dairy foods provide adequate protein and nutrients, and there’s no shortage of fat from nuts and seeds, avocado, olive oil, coconut, and other high-fat plant foods. For this subject, once his metabolic health was restored, he was able to increase his carb intake and maintain the improved health he achieved on strict keto. This is important because cultural and religious factors can make it difficult to follow a strict keto diet in certain places. Being able to include small amounts of higher carb staple foods (like rice and beans) while still improving metabolic health makes this way of eating more culturally compatible and more realistic for people to try.

Keto in Metabolic Psychiatry

Interest has exploded in keto diets for mental health. There’s growing awareness that many mental health conditions may be caused or worsened by brain energy problems rooted in metabolic dysregulation due to insulin resistance, nutrient deficiencies, hormone imbalances, and other factors. This has spawned the creation of a niche field called metabolic psychiatry. A paper published in Nature Mental Health outlined the scientific foundations of metabolic psychiatry and explained how interventions that target metabolism—including a keto diet—might be helpful for mental health issues.

Keto is anti-inflammatory, it improves mitochondrial function, helps maintain healthy blood sugar and insulin levels, and can help balance neurotransmitters involved in neuronal signaling and mood. Ketone molecules, specifically, are known to be a powerful and efficient fuel for the brain. For these and other reasons, the authors noted that keto can help restore normal brain energy metabolism and improve cognitive function and mental health.

(Learn more about keto for mental health here and here.) 

New Dietary Guidelines

While not specifically related to keto, the revamped Dietary Guidelines for Americans, released in January, made quite a splash in the keto community. The first page says it succinctly: “These Guidelines mark the most significant reset of federal nutrition policy in our nation’s history.”

The iconic food pyramid was turned upside down, with emphasis shifting away from starchy carbohydrates and toward “whole, nutrient-dense foods—protein, dairy, vegetables, fruits, healthy fats, and whole grains.” The guidelines encourage increased protein intake and consumption of full-fat dairy rather than low-fat or fat-free. Demonization of red meat and other animal foods is a thing of the past. The guidelines now say, “Consume a variety of protein foods from animal sources, including eggs, poultry, seafood, and red meat” while also mentioning beans and other plant protein sources.

Animal fats are back on the menu, too. The guidelines specifically include butter and beef tallow among the recommended fats to use for cooking, and they classify fat in meat, poultry, and eggs as “healthy fats.” The document still suggests getting no more than 10% of total calories from saturated fat, which could make it difficult to eat keto while following the guidelines, but overall, the changes are positive.

The new guidelines come down hard against processed food, refined carbs, and added sugars. This statement drew a lot of attention in the keto world: “Individuals with certain chronic diseases may experience improved health outcomes when following a lower carbohydrate diet.”

The Cholesterol Code Movie

Second only to the release of the 2025-2030 Dietary Guidelines, the biggest news in the keto world so far this year is the debut of The Cholesterol Code—a documentary about ketogenic diets, the effect of keto on blood cholesterol levels, and the role—or lack thereof—of elevated cholesterol in cardiovascular disease.

The movie is based on research by Dave Feldman and a team of physicians and researchers who posited the existence of the “lean-mass hyper-responder phenotype.” This phrase is used to describe people who had a normal cholesterol level before adopting a keto diet, but whose cholesterol skyrocketed after cutting carbs. The very high LDL-cholesterol occurs alongside high HDL-cholesterol and low triglycerides, and these people are typically lean and tend to be physically active.

The movie explores the science of cholesterol and cardiovascular disease, but the true highlights are the personal stories from people whose lives have been transformed via a keto diet. The individuals profiled are using keto to manage type 1 diabetes (with better blood sugar control than ever); keep bipolar disorder, major depression, and other mental health issues in remission or under control; and experience relief from food addiction. But along with unprecedented improvements in health and quality of life, keto also means their cholesterol is extremely high. Are they trading their new leases on life now for cardiovascular disease in the future, or is there more to heart disease than just the amount of cholesterol in your blood? The Cholesterol Code raises important questions not only for these specific individuals, but for anyone following a keto diet, as well as for the medical profession as a whole.  

Looking for More Keto Research?

Check out our previous roundup of studies on keto.