By Dr Laureen Lawlor-Smith, MD
Benefits of Low-Carb and Ketogenic Diets when Managing Metabolic Syndrome
Metabolic syndrome is a cluster of conditions that increase the risk of developing cardiovascular disease, type 2 diabetes, and stroke. The underlying causes include obesity, insulin resistance, physical inactivity, genetic factors, and aging. Early intervention through lifestyle changes such as a low carbohydrate diet) and medication (if needed) is crucial to manage the individual components and reduce the associated health risks.
According to the definition provided by the National Cholesterol Education Program (NCEP) Adult Treatment Panel III, a person is diagnosed with metabolic syndrome if they have three or more of the following conditions:
- Abdominal obesity (waist circumference >102 cm in men, >88 cm in women)
- Triglyceride levels ≥1.7mmol/L
- HDL cholesterol <1.0 mmol/L in men,<1.3 mmol/L in women
- Blood pressure ≥130/85 mmHg
- Fasting blood glucose ≥6mmol/L
Reducing carbohydrate intake can effectively improve the five symptoms commonly associated with metabolic syndrome. Carbohydrate reduction not only aids in weight loss but also enhances blood sugar control, insulin levels, triglyceride, and HDL levels, independent of weight loss.
How Insulin Resistance Contributes to Metabolic Syndrome
Insulin resistance is considered the core defect driving the development of metabolic syndrome for several reasons:
- Most people with metabolic syndrome have insulin resistance. Insulin resistance means the body's cells don't respond properly to the hormone insulin, which regulates blood sugar levels. This leads to high blood sugar and other metabolic abnormalities
- Insulin resistance precedes the development of other components of metabolic syndrome. Studies have shown that insulin resistance is present before conditions like high blood pressure, high triglycerides, and low HDL cholesterol develop
- Insulin resistance is closely linked to abdominal obesity, which is a major risk factor for metabolic syndrome. Excess fat in the abdomen is associated with insulin resistance and metabolic disturbances
- Insulin resistance is the cause of prediabetes and type 2 diabetes, which are closely tied to metabolic syndrome. Insulin resistance leads to high blood sugar levels that can progress to diabetes
- Reducing insulin resistance through lifestyle changes such as a low carbohydrate diet is a causative factor
In summary, insulin resistance appears to be the primary driver of metabolic syndrome, preceding and contributing to the development of the other components like obesity, high blood pressure, and dyslipidaemia. Targeting insulin resistance is, therefore, a key strategy for preventing and managing metabolic syndrome, and addressing insulin resistance through lifestyle changes, such as a low-carb ketogenic diet, is an excellent strategy for managing metabolic syndrome.
A Ketogenic Diet is Effective Against Metabolic Syndrome
A ketogenic diet, characterised by a very low-carbohydrate and high-fat diet intake, has been shown to be effective in improving various metabolic parameters associated with metabolic syndrome. The carbohydrate restriction and resulting ketosis in a ketogenic diet can significantly improve glycaemic control, weight loss, lipid profile, and other metabolic markers.
Blood Sugar Control
In patients with type 2 diabetes, a ketogenic diet leads to greater reductions in glycated haemoglobin (HbA1c) and improved insulin sensitivity compared to low-fat diets. This dietary pattern reduces carbohydrate intake, leading to a state of ketosis, where the body utilises fat as its primary energy source instead of glucose. This metabolic shift helps lower glucose levels and enhances insulin sensitivity, thereby improving overall blood sugar control. The reduced intake of carbohydrates means less glucose enters the bloodstream, which directly impacts insulin levels and sensitivity, making the ketogenic diet particularly beneficial for diabetic individuals.
Weight Loss
A ketogenic diet is effective for substantial weight reduction, irrespective of the patient's diabetes status at baseline. Weight loss on a ketogenic diet is often spontaneous due to reduced hunger and reduced calorie intake. The diet's high fat and moderate protein content help suppress hunger hormones like ghrelin while promoting satiety hormones such as peptide YY (PYY) and glucagon-like peptide-1 (GLP-1). As a result, individuals on a ketogenic diet tend to consume fewer calories, leading to significant weight loss. Additionally, the metabolic state of ketosis increases the body's fat-burning capacity, further contributing to weight reduction.
Lipid Profile
For diabetic patients, a ketogenic diet leads to lower triglyceride levels and higher HDL (good) cholesterol levels compared to low-fat diets. These improvements in lipid profiles are not limited to diabetic individuals but are observed broadly in those adhering to a ketogenic diet. Reduced triglycerides and elevated HDL levels are critical for cardiovascular health, and these changes can decrease the risk of cardiovascular diseases, which are common complications of metabolic syndrome.
Other Metabolic Markers
Beyond blood sugar control and lipid profiles, a ketogenic diet improves other metabolic markers such as visceral fat, inflammation, and blood pressure in patients with metabolic syndrome. The anti-inflammatory effects of ketosis contribute to lower levels of systemic inflammation, thereby improving overall metabolic health and reducing the risk of chronic diseases.
Summary
The available evidence suggests that a ketogenic diet can effectively improve the various components of metabolic syndrome, including glycaemic control, weight management, lipid profiles, and other metabolic markers, especially in patients with preexisting diabetes or obesity. A ketogenic diet can help manage the various components of metabolic syndrome and reduce the risk of associated health complications.
References
- What is Metabolic Syndrome? American Heart Association, 2024. https://www.heart.org/en/health-topics/metabolic-syndrome/about-metabolic-syndrome
- Metabolic syndrome. Better Health Channel. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/metabolic-syndrome
A comprehensive definition for metabolic syndrome. Huang, P., National Library of Medicine 2009. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675814/
- Metabolic Syndrome and Insulin Resistance: Underlying Causes and Modification by Exercise Training. Roberts, C., et al., National Library of Medicine 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129661/
- Metabolic Syndrome, Cleveland Clinic, 2023. https://my.clevelandclinic.org/health/diseases/10783-metabolic-syndrome
- Metabolic syndrome. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/metabolic-syndrome
- Impact of a Ketogenic Diet on Metabolic Parameters in Patients with Obesity or Overweight and with or without Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials. Choi, Y., et al., National Library of Medicine 2005. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7400909/
- Nutritional Ketosis for Weight Management and Reversal of Metabolic Syndrome. Gershundi, V., et al., National Library of Medicine 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6472268/
- A keto diet may help improve severe mental health, metabolic symptoms. Medical News Today. https://www.medicalnewstoday.com/articles/a-keto-diet-may-help-improve-severe-mental-health-metabolic-symptoms#How-does-the-keto-diet-improve-mental-health
Diet, the microbiome, and how insulin resistance causes metabolic syndrome. Fliesler, N., Boston Children's Hospital 2019. https://answers.childrenshospital.org/metabolic-syndrome-insulin-resistance/