- A ketogenic diet restricts carbohydrates to less than 50g per day, switching the body to burn fat for fuel
- When glucose is depleted, the liver produces ketones — an alternative fuel that also suppresses appetite
- Ketones reduce levels of hunger-driving hormones including insulin and ghrelin
- The diet carries real potential side effects and is difficult to sustain long-term
- Professional guidance from a dietitian is strongly recommended before starting
What Is the Ketogenic Diet?
The ketogenic ("keto") diet is a very low-carbohydrate eating pattern designed to shift the body's primary fuel source from glucose to fat-derived ketones. While there is no single standardised version, a ketogenic diet typically contains:
This is a high-fat, moderate-protein, very low-carbohydrate pattern — quite different from the high-protein diets some people associate with low-carb eating. The extreme restriction of carbohydrates is what drives the body into a metabolic state called ketosis.
How the Ketogenic Diet Produces Weight Loss
The mechanism behind ketogenic weight loss involves a gradual metabolic transition as the body is deprived of its preferred fuel:
When carbohydrate intake falls below approximately 50g per day, the body no longer receives enough glucose — its preferred and most readily available fuel — to meet its energy demands.
The body first draws on stored glucose (glycogen) from the liver, and temporarily breaks down muscle tissue to release additional glucose. This phase typically lasts 3–4 days.
As stored glucose is exhausted, blood insulin levels fall significantly. Lower insulin signals the body to stop storing fat and begin mobilising it for energy.
The liver begins converting fatty acids into ketone bodies, which serve as an alternative fuel for the brain and body. This state — nutritional ketosis — is the defining feature of the ketogenic diet and where most of its effects originate.
How Keto Suppresses Appetite
One of the reasons the ketogenic diet can support weight loss beyond simple calorie restriction is its effect on appetite. Two mechanisms contribute:
Potential Side Effects to Be Aware Of
The ketogenic diet is not without risk, and these effects are important to understand before starting:
The "keto flu" — a cluster of symptoms including headache, fatigue, brain fog, and irritability — is extremely common in the first 1–2 weeks as the body adapts to ketosis. It typically resolves on its own but can be distressing.
The ketogenic diet should be approached with professional guidance. Our dietitian team can assess whether it is appropriate for your health history and goals, help you implement it safely, and monitor for nutritional deficiencies and side effects over time.
If you're considering a ketogenic diet as part of your weight management journey, we'd recommend speaking with one of our dietitians or booking a consultation with a MedSurg doctor first. Get in touch to find out more.
Medical disclaimer: This article is for general informational purposes only. The ketogenic diet is not appropriate for everyone and carries potential risks, particularly for people with diabetes, kidney disease, liver disease, or a history of eating disorders. Please consult your doctor or a qualified dietitian before starting any restrictive dietary pattern.