Keto and Metabolic Syndrome: Score Your Five Markers Today

The research on keto and metabolic syndrome is promising but early. A scoping review in Frontiers in Nutrition mapped ketogenic diet studies from 2015 to 2025 and found them linked to lower body weight, triglycerides and fasting glucose, better insulin sensitivity and higher HDL. A scoping review maps the evidence and does not weigh it, so treat it as a list of markers worth testing on yourself, not proof that keto will fix any of them.

What did the new review on keto and metabolic syndrome actually measure?

The review looked at ketogenic diet studies in people with metabolic syndrome and listed the outcomes they reported, one marker at a time. The evidence says the authors searched six databases under PRISMA-ScR rules and included English-language studies published between 2015 and 2025.

Here is the real problem with most diet headlines. They give you one number and call it health. Metabolic syndrome is not one number. It is a cluster, and the review itself lists the criteria: abdominal obesity, blood pressure of 130/85 mmHg or more, fasting glucose of 100 mg/dL or more, triglycerides of 150 mg/dL or more, and HDL under 40 mg/dL in men or under 50 mg/dL in women.

That is why this paper is worth your time. It is one of the first 2026 syntheses to put keto next to every one of those markers at once, instead of picking the one that flatters the diet.

Which metabolic syndrome markers does the review back most strongly?

The strongest signals are triglycerides, fasting glucose and HbA1c, and body weight. The evidence says the included studies showed a reduction in HbA1c, fasting glucose, body weight and triglycerides, along with a rise in HDL.

Let me number the truths, marker by marker.

• Triglycerides: the most consistent drop. I have written about why the triglyceride trend actually matters.
• Fasting glucose and insulin sensitivity: improved across many studies, with the review also describing lower inflammation.
• HDL: tends to rise, which moves you away from the low-HDL criterion.
• Waist and visceral fat: improved with weight loss. Fat around the organs links to the liver too, which is why I covered keto and liver fat separately.
• Blood pressure: less settled in this review, though a network meta-analysis of metabolic syndrome trials found the ketogenic diet was more effective at lowering blood pressure and triglycerides, while Mediterranean eating did better on fasting glucose.

Sit with that last line for a moment. Even the studies that favour keto do not hand it every marker.

Why is a scoping review weaker than a meta-analysis?

A scoping review counts and describes the studies; it does not pool their results or grade how trustworthy each one is. The evidence says scoping reviews map a field and its knowledge gaps, and risk-of-bias or quality checks are not mandatory.

So a study with a few patients and a strong trial can sit side by side on the same map. The inclusion criteria even allowed studies in both humans and animals. That is not a flaw in the method. It is the method. You just cannot read it as a verdict.

The authors are honest about the costs too. They write that the diet requires cutting many foods, which can lead to “nutritional monotony, reduced quality of life and the risk of eating disorders.” I cover the same gap in why the carnivore evidence is so thin.

How do I score myself for metabolic syndrome at home?

You need a standard blood panel, a blood pressure reading and a tape measure, and you count how many of the five criteria you meet. Under the 2009 AHA, NHLBI and IDF consensus, three of the five defines metabolic syndrome.

Here is the test

• Waist: measure at the navel, standing relaxed, after you breathe out. Do not suck in. Nobody is grading your vanity.
• Blood pressure: seated, rested, arm at heart level, more than one reading.
• Fasting glucose, triglycerides and HDL: a fasting lipid panel and a metabolic panel cover all three. My list of what to ask for is a good starting point.

Write each result next to the cut-offs from the first section. Score one point per marker over the line. Then do it again in three months, the same way, at the same time of day. If you aren’t testing, you’re guessing.

Do these patients look anything like Dr. Mike?

No. The review studied people who already met the criteria for metabolic syndrome, and Dr. Mike started the 30 days as a fit doctor. That is the entire stakes of reading any of this.

The film shows Dr. Mike eating 20 Burger King patties a day, no bun, water only, for 30 days. The film shows his baseline draw covering a CBC, thyroid hormones, inflammatory markers, and vitamin and mineral panels. The book lists hormone, cardiometabolic, liver, thyroid, kidney and inflammatory panels across four test points. The film suggests, through his own on-camera prediction, that he expected inflammation to climb. Whether it did is in the film, not here.

I picked a fit man on purpose, and I explained why in why a fit doctor eats 600 burgers. A body with three markers over the line has room to improve. A body already under every line has room only to fall. Individual results vary, and this experiment is about as far from a clinical trial as you can get.

What does the 600-burger month add that a review cannot?

It adds what a person feels while the markers are being drawn. A review reports averages. A journal reports mornings.

Dr. Mike wrote on Day 5 about his first dizzy spell on standing. Dr. Mike wrote on Day 13 that his left hand cramped three times and that he suspected electrolyte and micronutrient deficiencies. Dr. Mike wrote on Day 19 that his HRV had been cut in half a week in, and Chantea told him “it means you’re getting sick mike.” None of that shows up on a scoping review’s results table.

In my experience, the patients who stick with a change are the ones who track both: the panel and the way they feel at 2 pm. One vehicle, one body. The body keeps the score, and you only read it if you test.

Frequently asked questions

Many people report early symptoms. An analysis of online posts described ‘keto flu’ as headache, fatigue, nausea, dizziness and gut upset, mostly in the first week and fading within weeks, though these were self-reports, not measurements (https://pubmed.ncbi.nlm.nih.gov/32232045/). Persistent symptoms are a reason to see a clinician, not to push harder.

The trials are small and mixed. A randomised pilot in military personnel found two weeks of keto induction did not change sleep, cognition or mood, though heart rate variability tended to fall (https://pubmed.ncbi.nlm.nih.gov/35729758/). Wrist trackers also overcount sleep, so treat a Fitbit trend as a rough guide, not a sleep study.

Start with a baseline panel, a waist measurement and a blood pressure reading, then keep carbohydrates low and food whole. A dose-response meta-analysis found cardiometabolic markers improved roughly in step with carbohydrate cuts in type 2 diabetes (https://pubmed.ncbi.nlm.nih.gov/35537861/). Retest on the same schedule so you compare like with like.

Simple meals built from protein, non-starchy vegetables and whole-food fats are the easiest to sustain. The review’s authors warn that monotony is a real risk on a restrictive diet, so variety is part of the method, not a luxury (https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2026.1858811/full). Dr. Mike’s single-food month shows what the opposite looks like.

It depends on body weight. A meta-analysis of trials found LDL-C rose substantially on low-carb diets in people of normal weight but not in those with a high BMI (https://pubmed.ncbi.nlm.nih.gov/38237807/). LDL is not one of the five metabolic syndrome criteria, so check it separately on your panel.

The Bottom Line

The new review gives keto and metabolic syndrome a promising map: triglycerides, glucose, weight and HDL are where the studies point most often. A map is not a verdict. Score your five markers, write them down, and retest the same way. That is the work only you can do, and your clinician is the person to read the numbers with you.

If you want to see what happens when a body that starts under every line gets pushed the other way, the whole story is told day by day in the book. Get 600 Burgers in 30 Days, and find out how the 30 days end. What will you do with your own numbers?

Sources

• The impact of the ketogenic diet on the health of patients with metabolic syndrome: a scoping review (Frontiers in Nutrition, full text)
• The impact of the ketogenic diet on the health of patients with metabolic syndrome: a scoping review (PDF)
• The impact of the ketogenic diet on the health of patients with metabolic syndrome (PMC)
• Network meta-analysis of the effects of different dietary patterns on patients with metabolic syndrome
• Clinical Feature: Cardiometabolic Syndrome: A Package Deal (National Lipid Association)
• Systematic reviews in Speech-Language Pathology (PMC)
• Consumer Reports of Keto Flu Associated With the Ketogenic Diet
• Cognitive, Sleep, and Autonomic Responses to Induction of a Ketogenic Diet in Military Personnel
• Dose-dependent effect of carbohydrate restriction for type 2 diabetes management
• Increased LDL cholesterol on a low-carbohydrate diet in adults with normal but not high body weight