Traditional weight-loss methods include low-calorie diets
between 800 to 1500 calories a day and regular exercise. An
alternative method sometimes considered for significant short-term
weight loss in moderately to severely obese people is the very
low-calorie diet (VLCD).
What is a very low-calorie diet (VLCD)?
VLCDs are doctor-supervised diets that provide an individual 800
calories or fewer per day. These diets typically involve the use
of a commercially prepared formula, but some physicians prescribe
VLCDs made up of lean protein foods. Formulas prescribed by a
physician for these diets are not the same as those you can find in
a drug- or grocery store. VLCDs, when used under proper medical
supervision, effectively produce significant short-term weight loss
in moderately to severely obese patients.
Who should use a VLCD?
VLCDs are generally safe when used short term under proper
medical supervision in patients with a body mass index (BMI)
greater than 30. BMI is a mathematical formula that takes into
account a person's height and weight. To calculate BMI, a person's
weight in kilograms is divided by height in meters squared. Use of
VLCDs in patients with a BMI of 27 to 30 should be reserved for
those who have medical complications resulting from their obesity.
VLCDs are not recommended for women who are pregnant or
breastfeeding, and are not appropriate for children or adolescents,
except in specialized treatment programs. There is also little
research available to support using VLCD's in people over the age
of 50. The decision to treat an individual of this age with a VLCD
should be made on a case-by-case basis by a physician.
People with significant medical problems or who are on
medications may be able to use a VLCD, but this must also be
determined on an individual basis by a physician.
Health benefits associated with a VLCD
A VLCD may allow a severely to moderately obese patient to lose
about 3 to 5 pounds per week, for an average total weight loss of
44 pounds over 12 weeks. Such a weight loss can improve
obesity-related medical conditions, including diabetes, high blood
pressure, and high cholesterol. Combining a VLCD with behavioral
therapy and exercise may also increase weight loss and may slow
weight regain. However, VLCDs are no more effective than more
modest dietary restrictions in the long-term maintenance of reduced
Adverse effects associated with a VLCD
Many patients on a VLCD for 4 to 16 weeks report minor side
effects such as fatigue, constipation, nausea, and diarrhea. These
conditions usually improve within a few weeks and rarely prevent
patients from completing the program. The most common serious side
effect seen with VLCDs is gallstone formation. Gallstones, which
often develop in obese people anyway (especially women), are even
more common during rapid weight loss. Some research indicates that
rapid weight loss appears to decrease the gallbladder's ability to
contract bile. It is unclear whether VLCDs directly cause
gallstones or whether the amount of weight loss is responsible for
the formation of gallstones.
For most obese individuals, obesity is a long-term condition
that requires a lifetime of attention, even after a formal
weight-loss treatment ends. Although VLCDs are efficient for
short-term weight loss, they are no more effective than other
dietary treatments in the long-term maintenance of reduced weight.
Therefore, obese patients should commit to a long-term treatment
program that includes permanent lifestyle changes including
healthier eating, regular physical activity, and an improved
outlook on food. Without a long-term commitment, they will regain
Source: National Institutes of Health (NIH) NIH Publication 03-3894, Very Low-calorie Diets. January 2003/Updated June 2006
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