Very Low-calorie

Diets

WIN Weight-control Information Network 

Obesity affects one-third

of adults in the United

States, increasing their

risk for diabetes, high

blood pressure, and

heart disease. Traditional

weight-loss methods

include low-calorie

diets, ranging from 800

to 1,500 calories per

day, and regular physical activity. Health care

providers sometimes

consider an alternative

method for bringing

about significant shortterm weight loss in

patients who are moderately to extremely

obese: the very lowcalorie diet.

What is a very low-calorie diet?

A very low-calorie diet (VLCD) is a doctor-supervised diet that

typically uses commercially prepared formulas to promote rapid

weight loss in patients who are obese. These formulas, usually liquid

shakes or bars, replace all food intake for several weeks or months.

VLCD formulas need to contain appropriate levels of vitamins and

micronutrients to ensure that patients meet their nutritional

requirements. Some physicians also prescribe very low-calorie diets

made up almost entirely of lean protein foods, such as fish and

chicken. People on a VLCD consume about 800 calories per day

or less. 

VLCD formulas are not the same as the meal replacements you can

find at grocery stores or pharmacies, which are meant to subsitute

for one or two meals a day. Over-the-counter meal replacements

such as bars, entrees, or shakes should account for only part of one’s

daily calories.

When used under proper medical supervision, VLCDs may produce

significant short-term weight loss in patients who are moderately to

extremely obese. VLCDs should be part of comprehensive weightloss treatment programs that include behavioral therapy, nutrition

counseling, physical activity, and/or drug treatment.

Who should use a VLCD?

VLCDs are designed to produce rapid weight loss at the start of a

weight-loss program in patients with a body mass index (BMI)

greater than 30 and significant comorbidities. BMI correlates

significantly with total body fat content. It is calculated by dividing

a person’s weight in pounds by height in inches squared and multiplied by 703. 

Use of VLCDs in patients with a BMI of 27 to 30 should be

reserved for those who have medical conditions due to overweight,

such as high blood pressure. These diets are not appropriate for

children or adolescents, except in specialized treatment programs.

NATIONAL INSTITUTES OF HEALTH
2

Very little information exists regarding the use of

VLCDs in older people. Because people over age

50 already experience depletion of lean body

mass, use of a VLCD may not be warranted. Also,

people over 50 may not tolerate the side effects

associated with VLCDs because of preexisting

medical conditions or the need for other

medicines. Doctors must evaluate on a case-bycase basis the potential risks and benefits of rapid

weight loss in older adults, as well as in patients

who have significant medical problems or are

on medications.

Health Benefits of a VLCD

A VLCD may allow a patient who is moderately

to extremely obese 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

rapidly improve obesity-related medical conditions, including diabetes, high blood pressure,

and high cholesterol.

The rapid weight loss experienced by most people

on a VLCD can be very motivating. Patients who

participate in a VLCD program that includes

lifestyle treatment typically lose about 15 to 25

percent of their initial weight during the first 3 to

6 months. They may maintain a 5-percent weight

loss after 4 years if they adopt a healthy eating

plan and physical activity habits.

Adverse Effects of a VLCD

Many patients on a VLCD for 4 to 16 weeks

report minor side effects such as fatigue, constipation, nausea, or diarrhea. These conditions

usually improve within a few weeks and rarely

prevent patients from completing the program.

The most common serious side effect is gallstone

formation. Gallstones, which often develop in

people who are obese, especially women, are

even more common during rapid weight loss.

Research indicates that rapid weight loss may

increase cholesterol levels in the gallbladder and

decrease its ability to contract and expel bile.

Some medicines can prevent gallstone formation

during rapid weight loss. Your health care

provider can determine if these medicines are

appropriate for you.

Maintaining Weight Loss

Studies show that the long-term results of

VLCDs vary widely, but weight regain is common. Combining a VLCD with behavior

therapy, physical activity, and active follow-up

treatment may help increase weight loss and

prevent weight regain.

In addition, VLCDs may be no more effective

than less severe dietary restrictions in the long

run. Studies have shown that following a diet of

approximately 800 to 1,000 calories produces

weight loss similar to that seen with VLCDs. This

is probably due to participants’ better compliance

with a less restrictive diet.

For most people who are obese, obesity is a

long-term condition that requires a lifetime of

attention even after formal weight-loss treatment

ends. Therefore, health care providers should

encourage patients who are obese to commit to

permanent changes of healthier eating, regular

physical activity, and an improved outlook about

food.

*Endnote: This fact sheet is an updated, modified version of a previously published review

article appearing in the August 25, 1993 issue of

the Journal of the American Medical Association.

Both the review article and this fact sheet were

developed with the advice of the Clinical

Obesity Research Panel, formerly known as the

National Task Force on Prevention and

Treatment of Obesity.

Additional Reading 

Dieting and Gallstones. National Institutes of

Health (NIH) Publication No. 02–3677.

February 2002. Updated April 2006. 

Active at Any Size. NIH Publication No.

04–4352. April 2004.
3

Weight-control

Information Network

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The Weight-control Information

Network (WIN) is a national information service of the National Institute of

Diabetes and Digestive and Kidney

Diseases (NIDDK) of the National

Institutes of Health, which is the

Federal Government’s lead agency

responsible for biomedical research on

nutrition and obesity. Authorized by

Congress (Public Law 103-43), WIN

provides the general public, health

professionals, the media, and

Congress with up-to-date, sciencebased health information on weight

control, obesity, physical activity, and

related nutritional issues. 

Publications produced by WIN are

reviewed by both NIDDK scientists

and outside experts. This fact sheet

was also reviewed by Rena Wing,

Ph.D., Professor, Brown University

and University of Pittsburgh School of

Medicine.

This publication is not copyrighted. WIN encourages users of this fact sheet to duplicate and distribute as many copies as desired. 

This fact sheet is also available at

www.win.niddk.nih.gov

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Institutes of Health

NIH Publication No. 03-3894

January 2003

Updated June 2006

Better Health and You: Tips for Adults. Part of the series Healthy

Eating and Physical Activity Across Your Lifespan. NIH Publication

No. 04–4992. Revised March 2006. 

To request a free publication, call the Weight-control Information

Network at 1–877–946–4627 or log on to www.win.niddk.nih.gov.