Patient Suitability


Normal weight (BMI)

VLCDs should never be used by normal weight subjects because it may lead to excessive loss of lean body mass.

If your patient’s BMI is under 25kg/m2 you may consider starting them on either the Active 2 or Active 1 levels of the OPTIFAST VLCD Program.


OPTIFAST VLCD is contraindicated during pregnancy for a number of reasons.

The low carbohydrate content is designed to induce ketosis (fat breakdown) which leads to ketones in the blood. Although the levels of ketones are fairly low, the effect on the foetus is unknown.

In addition, the OPTIFAST VLCD Program is not designed to meet the increased nutrient requirements of pregnancy (e.g. protein, iron and some B group vitamins).


The Intensive level of the OPTIFAST VLCD Program (replacing all 3 meals with OPTIFAST VLCD products) is not recommended for women who are breastfeeding as it is not designed to meet the increased nutritional demands of lactation.

Patients may start on the Active 1 level (ie replacing one meal per day with an OPTIFAST VLCD product). They can gradually increase the amount of meals replaced once the baby has started to wean off breast milk and is also consuming a reasonable quantity of solids.

Children <18 years

VLCDs are contraindicated in children who are still growing; however there may be children in whom severe obesity is resistant to other treatments.

In such individuals the risks associated with obesity should be weighed against the risks of using a VLCD and should only be prescribed and monitored by a qualified healthcare professional.

Presence of porphyria

Porphyria is the umbrella term for a group of rare disorders that involve a particular molecule called ‘haem’. Haem contains iron and is used in metabolic processes throughout the body.

Porphyria occurs when the body cannot convert naturally occurring compounds (called ‘porphyrins’) into haem. While all tissues have haem, those that use it the most are the red blood cells, liver and bone marrow. Porphyria can affect the skin, nervous system and gastrointestinal system, depending on the specific type.

Porphyria is contraindicated with OPTIFAST VLCD as extreme calorie restriction can provoke an acute attack.

Recent myocardial infarction or unstable angina

Patients should be referred to a cardiologist to determine suitability for a VLCD or severe calorie restriction.

Severe / advanced renal or liver failure

Persons with advanced liver or renal disease are not suitable for the OPTIFAST VLCD Program, as they may require altered intakes of electrolytes and nutrients.

View the precauctions for patients when investigating the OPTIFAST VLCD Program. 

Go to the indications.