Ketosis is a metabolic reaction that occurs in your body when following the OPTIFAST® VLCD™ Program Intensive Level. This means your body shifts from using primarily carbohydrates to using fats as an energy source, resulting in a reduction of body fat stores.
Ketones provide an alternative fuel source derived from fat when carbohydrates are in short supply. It has been suggested that ketosis may suppress appetite which helps make following the OPTIFAST® VLCD™ Program Intensive Level much easier. As the Intensive Level causes only a mild ketosis, it is a safe approach to weight loss.
Prior to the transition into ketosis, you will most likely feel hungry and you may experience some side-effects such as:
- Fatigue
- Lack of concentration
- Nausea
- Headaches
These side-effects should only last about 3 days and most symptoms usually pass by days 4-6. This is what we refer to as the ‘3 day challenge’. Following the initial 3 day challenge you will experience an increase in energy and reduction in appetite which, in the Intensive Level, will result in consistent and successful weight loss. It is important to know that these are typical symptoms and you should try to stick to the program as prescribed or otherwise you will simply pro-long these uncomfortable first few days of the OPTIFAST® VLCD™ Program.
Of course, if you are concerned about your symptoms or if they persist, speak to a healthcare professional such as your doctor, dietitian or pharmacist as they can advise how to overcome or correct these symptoms before coming off the program.
Once your body is in ketosis, any excess ketones that your body does not use for energy are excreted via your urine and breath (thus the incidence of bad breath in some cases). Measuring ketone levels can be used as a guide to assessing how you are managing the OPTIFAST® VLCD™ Program. Urine ketones can be measured using ketone reagent strips, which can be purchased over the counter from your local pharmacy. Alternatively, blood monitors and breath analysers are also available for measuring ketone levels. Your healthcare professional may test for ketones on your regular visits.
So don’t worry if you have a little bad breath whilst on the program. This will only occur and last if you are following the Intensive Level. Chewing on a low-calorie mint, sugar free chewing gum or even parsley can be very effective in managing this.
The amount of carbohydrate required to induce ketosis depends on a number of factors and can actually vary from day to day depending on activity levels and fluid intake.
A diet containing 50-70g carbohydrate is generally considered low enough to produce ketones but there is no absolute level that guarantees ketone production. The OPTIFAST® VLCD™ Program generally only produces a mild ketosis, and therefore some people find that ketone reagent strips do not show ketones or the levels fluctuate. If you are losing weight steadily, then there is no need to be concerned. You can rely on the other symptoms of ketosis such as a reduction in your appetite and change in your breath as a guide instead.
OPTIFAST VLCD is for the dietary management of obesity and must be used under the supervision of a healthcare professional.
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