From the Guidelines
A very low calorie diet (VLCD) for weight loss is defined as a diet providing 800-1,000 calories per day, and should only be prescribed to carefully selected individuals by trained practitioners in medical settings with close monitoring. This definition is based on the most recent and highest quality study available, which emphasizes the importance of careful selection and monitoring of individuals undergoing VLCDs 1. The use of VLCDs is considered a medical intervention and should be reserved for short periods of 8-16 weeks, typically for individuals with BMIs over 30 or those with BMIs over 27 who have weight-related medical conditions.
Some key points to consider when implementing a VLCD include:
- The diet should provide adequate protein, at least 70-100g daily, while severely restricting carbohydrates and fats
- The diet should be used under healthcare supervision to minimize risks, including gallstones, muscle loss, nutrient deficiencies, and metabolic adaptations that can make weight maintenance difficult
- Less restrictive approaches of 1,200-1,500 calories daily may be safer and more sustainable for most people seeking weight loss
- VLCDs are contraindicated during pregnancy, for people with certain medical conditions, or those with eating disorders
It is also important to note that effective long-term weight maintenance programs should provide ongoing support, monthly contact, and encourage regular physical activity, as well as frequent self-monitoring of body weight and other self-monitoring strategies 1. Additionally, reducing processed and ultraprocessed food intake is an encouraging area of ongoing weight loss research, and nutritional supplements have not been shown to be effective for weight loss and are not recommended 1.
From the Research
Definition of a Very Low Calorie Diet (VLCD)
A very low calorie diet (VLCD) is typically defined as a diet with an average intake of less than 800 kcal per day 2.
Characteristics of VLCDs
Some key characteristics of VLCDs include:
- Average intake between 400 and 800 kcal per day 3
- Can be used as part of an integrated intervention, including medical monitoring and lifestyle modification, to improve various clinical states 2
- Often used for the initial treatment of obesity, with the goal of achieving rapid weight loss and improving complications of obesity 4
Safety and Effectiveness of VLCDs
Studies have shown that VLCDs can be an effective and safe means of substantial weight reduction, with careful medical and laboratory monitoring 5. However, it is also noted that long-term weight loss requires lifestyle changes in eating and activity patterns, and that VLCDs should be used under the close supervision of a health professional team 4.
Examples of VLCDs
Examples of VLCDs include: