Very Low-calorie

Diets

U.S. DEPARTMENT OF HEALTH

AND HUMAN SERVICES

NATIONAL INSTITUTES OF HEALTH

WIN Weight-control Information Network

A very

low-calorie

diet is a doctorsupervised

diet that

typically uses

commercially

prepared

formulas to

promote rapid

weight loss in

patients who

are obese.

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 VLCDs

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

substitute 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 weight-loss 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.
2

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. In fact, all candidates

for VLCDs undergo a thorough examination

by their health care provider to make sure the

diet will not worsen preexisting medical

conditions. Lastly, these diets are not

appropriate for children or adolescents,

except in specialized treatment programs.

Very little information exists regarding the use

of VLCDs in older adults. Because adults 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-by-case 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. Furthermore, doctors must

monitor all VLCD patients regularly—ideally

every 2 weeks in the initial period of rapid

weight loss—to be sure patients are not

experiencing serious side effects.

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, their

condition is long-term and requires a lifetime

of attention even after formal weight-loss
3

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

Active at Any Size. Revised October 2006.

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

Healthy Eating and Physical Activity Across Your Lifespan.

Revised March 2006.

Dieting and Gallstones. Revised July 2008.

Weight Cycling. Revised May 2008.

Weight Loss for Life. Revised July 2006.

Weight-control

Information

Network

1 WIN Way

Bethesda, MD 20892–3665

Phone:

(202) 828–1025

Toll-free number:

1–877–946–4627

FAX: (202) 828–1028

Email:

WIN@info.niddk.nih.gov

Internet:

http://www.win.niddk.nih.gov

The Weight-control Information

Network (WIN) is a 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

publication was also reviewed by

Rena Wing, Ph.D., Professor of

Psychiatry and Human Behavior,

Brown University.

This fact sheet is also available at

http://www.win.niddk.nih.gov.

This publication is not

copyrighted. WIN encourages

users of this fact sheet to

duplicate and distribute as

NIH Publication No. 03–3894 many copies as desired.

August 2008