Ketogenic Very Low Calorie Diet (VLCD)

What Is a Ketogenic Very Low Calorie Diet?

• A ketogenic VLCD is a diet that provides <3300 kj per day (800 kcal) and induces ketosis by limiting carbohydrate intake to ≤ 50-60 g per day.
• Ketosis is an important factor in this diet as it overcomes some of the compensatory physiological responses such as increased ghrelin and appetite which usually arise during dieting and weight loss. Reduced appetite makes the diet easier to stick to for patients
• It is intended as an intensive intervention resulting in rapid and large weight loss
• It aims to reduce weight without introducing any of the risks associated with starvation such as micronutrient/protein deficiencies or electrolyte imbalance
• It typically includes meal replacement products that are specifically formulated to ensure that essential nutritional requirements are met. These are consumed instead of normal meals
• The VLCD should contain 0.8-1.0 g per kg body weight of high-quality protein per day
• Adherence to a VLCD typically results in a weekly weight loss of around 1.5-2 kg⁸

Ketogenic Very Low-Calorie Diet Evidence

The Royal Australian College of General Practitioners guidelines for obesity management indicate the use of very low energy (calorie) diet to induce rapid weight loss for those of BMI > 30 kg/m2 or those with BMI > 27 kg/m2 who also suffer comorbidities.⁹ The ketogenic VLCD is a good option for a very low energy diet since the ketogenic aspect of the diet suppresses hunger and therefore aids adherence. It is widely accepted that ketosis suppresses hunger,^{10, 11}, however the specific mechanism by which ketosis reduces appetite has not been definitively determined.¹¹

A ketogenic VLCD delivered using up to 2 meal replacements per day is an appropriate and simple dietary intervention, and has been shown to be safe in adults up to 80 years of age.¹² This rapid rate of weight loss means that people with overweight or obesity adhering to a ketogenic VLCD frequently achieve a 10-15% weight loss target weight within 12 weeks.

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Resources for patients and health professionals offering support

Individuals need to be informed and supported to be able to adhere to a low carbohydrate diet which will keep them in ketosis. Commercial providers of meal replacements provide phone applications or PDF documents through their website so individuals on the diet have resources or tools to check what they can and can’t eat for their meal or snacks (if required). For some examples, explore the resources on the Optifast website here.