A Very Low Calorie Diet, also known as a Very Low Energy Diet, is a diet that was originally invented for rapid weight loss to assist people to lose weight quickly in preparation for weight loss surgery, such as gastric bypasses surgery. Today, they are also used to help very obese people to lose weight quickly in order to reduce the effects of weight related medical conditions as well, such as Type II diabetes. The most popular VLCD diets in Australia are Optifast and Optislim.
VLCD diets typically involve consuming 3,300kJ (800 calories) per day or less, by consuming only specially formulated and fortified meal replacement shakes. Very often, these shakes have limited or varied amounts of carbohydrate (consistent with a low carb diet) to induce Ketosis. VLCD diets are designed to be used under medical supervision.
People who are able to stick to a VLCD diet can expect to lose between 1½ to 2½ kilos per week if they have a significant amount of weight to lose.
But it’s not all good news…
Potential adverse effects of a prolonged use of a VLCD diet include:
- Headaches and bad breath (resulting from Ketosis)
- Heart problems
- Loss of lean muscle mass
- Electrolyte imbalances
It has even been suggested that in extreme cases, sudden death can also be a side effect of VLCD diets from ventricular tachycardia, resulting from insufficient macronutrient & mineral intake.
Regardless of the risks, there are some people should avoid VLCD and other meal replacement diets altogether. These include:
- Children and infants
- Adolescents under 18
- Adults over 65
- Pregnant women
- Breast-feeding women
Marketing of VLCD Diets
In order to sell VLCD meal replacement shakes and other meal replacement products to everybody who wants to lose weight, marketers of diet shakes and associated products, (diet soups, diet bars, protein bars, calorie controlled snacks, etc.) have devised eating plans that incorporate their shakes.
In order to get around the fact that people can’t stay on very low calorie diets for a long time (by choice as well as medical reasons), these marketers have developed phased diets or eating plans around their shakes. These plans very often start off at 800 calories per day and move to 1,000 to 1200 calories per day, 1200 to 1500 calories per day, etc., right up to the average daily recommended intake for adults which is around 2,000 calories per day.
For example, their VLCD diet may have an initial phase where you consume only 3 diet shakes per day, a second phase where you consume two shakes per day, and a third and fourth phase where you consume only one shake per day as a form of weight maintenance, or just snack on their protein bars.
To help you navigate these phases, they’ll often give you a simple diet plan as a guide, and may offer supporting recipes as low calorie meal options.
VLCDs also come disguised as various fad diets, such as the Cabbage Soup Diet or Grapefruit Diet (also called the Hollywood Diet).
Do VLCD Diets Work Long Term?
There are many studies that show that VLCD diets can work well in the short term.
Unfortunately, there are also many studies that also show that for most people they don’t work in the long term.
These studies suggest that a more graduate weight loss works better for the long term, because this usually involves lifestyle changes.
Does that mean that all meal replacements won’t help people lose weight in the long-term? Absolutely not. Many studies show that meal replacement shakes can be a very effective and convenient too to help with long term weight loss, when used in conjunction with a healthy diet and moderate exercise.
The key to finding a weight loss shake that you can live with is taste. Because they contain high proportions of protein and vitamins, many diet shakes don’t taste very nice. Unfortunately, most VLCD shakes fall into this category. If you want to lose weight using shakes, find a great tasting diet shake that you’ll be happy to drink long term, and don’t worry too much about the details of how many calories they are, how much protein and what levels of nutrients they have, as many of them are pretty close on these aspects.
Because of the potential risks associated with being on a VLCD diet, it is highly recommended that they are used under the strict supervision of a Doctor or Dietitian.
As with any diet, it is recommended that you speak to you doctor before going on any weight loss program.
This article was written by Scott Haywood.
Scott is the editor of weightloss.com.au. Scott has developed an expertise in fitness and nutrition, and their roles in weight loss, which led him to launch weightloss.com.au in 2005. Today, weightloss.com.au provides weight loss and fitness information, including hundreds of healthy recipes, weight loss tools and tips, articles, and more, to millions of people around the world, helping them to lead happier, healthier, lives.
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