Obesity Treatment Low Calorie Diet

Unlike other weight loss diets, a low-calorie diet limits daily caloric intake to 800 to 1,500 calories. Low-calorie foods include fruits, vegetables, whole grains and lean protein. When combined with exercise, low-calorie meals can result in a loss of one to two pounds a week.

Weight loss diets that allow fewer than 800 calories a day are known as “very low-calorie diets” or VLCDs. Since a very low-calorie diet can result in rapid weight loss, it requires medical supervision.

Very Low-Calorie Diets and Weight Loss

When done safely, a very low-calorie diet produces significant weight loss — a moderately to severely obese person can lose three to five pounds a week. These diets require people to eat a diet of low-calorie foods for three to six months. According to the Cleveland Clinic (2009), the average dieter loses 44 pounds after 12 weeks on a very low-calorie diet.

Types of Very Low-Calorie Diets

A doctor-supervised VLCD typically replaces meals with liquid formulas and meal bars with sufficient nutrients and vitamins. VLCD formulas are not the same as over-the-counter meal replacement bars or diet shakes, which aren’t intended for long-term use. Lean protein diets may also be prescribed as very low-calorie meals.

Many fad diets, including the Hollywood diet, claim to be very low-calorie weight loss diets. Although you do consume low-calorie foods on such diets, these low-calorie meals often lack the nutritional balance found in a medically supervised VLCD.

Very Low-Calorie Diet Side Effects

Whether the VLCD is a lean protein diets or based on dietary formulas, it must be carefully supervised. Consuming fewer than 800 calories a day from low-calorie foods makes it difficult to maintain proper nutrient levels. You’ll want to get regular checkups if you’re on this type of weight loss diet.

Common side effects of a low-calorie weight loss diet — which usually resolve on their own — include constipation, diarrhea, fatigue, gallstones and nausea.

When to Avoid Very Low-Calorie Diets

Limiting oneself to low-calorie meals isn’t for everyone. These diets aren’t recommended for adolescents, children or pregnant women.

People over 50 may also have difficulty tolerating a very low-calorie diet and its side effects, especially if they take medication or have preexisting medical conditions.

Anyone considering a very low-calorie diet should first consult with a medical professional. Most doctors determine the need for a VLCD on a case-by-case basis.

How Effective Is a Very Low-Calorie Diet?

Although a VLCD produces significant short-term weight loss, without changes to behavior, eating habits and exercise, it’s often difficult to maintain the new weight.

Over the long term, a low-calorie diet of 800 to 1,500 calories appears to be just as effective as a VLCD, which is best for those who need to lose weight quickly to counteract the effects of obesity-related health complications.


Cleveland Clinic. (2009). Very low-calorie diets. Retrieved April 25, 2010, from http://my.clevelandclinic.org/disorders/obesity/hic_very_low-calorie_diets.aspx.

National Institute of Diabetes and Digestive and Kidney Diseases. (2008). Very low-calorie diets. Retrieved April 25, 2010, from http://www.win.niddk.nih.gov/publications/low_calorie.htm.

MedicineNet. (2006). Definition of very low-calorie diet (VLCD). Retrieved April 25, 2010, from http://www.medterms.com/script/main/art.asp?articlekey=76935.