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Diseases & Conditions

PSMF Diet Program

(Also Called 'PSMF Diet Program - Diet')

Obesity is a primary health concern and a risk factor for coronary heart disease, diabetes, gall bladder disease, arthritis, and peripheral vascular disease. Weight loss can make a significant contribution to improving general health and well-being. The Protein-Sparing Modified Fast (PSMF) is designed for rapid weight loss and incorporates medical, nutritional, and behavioral components. The goal of this diet is to reach an appropriate body weight as determined by your physician and dietitian.

Carbohydrate, protein, and fat are the nutrients in food that provide energy for proper functioning, maintenance, and repair of the body. In addition to these three nutrients, the human body requires water, vitamins, and minerals for good health.

While on the PSMF program, only lean meat, seafood, poultry, and a limited amount of low-carbohydrate vegetables should be eaten. Carbohydrates and additional forms of fat are not allowed on this program. The high protein intake is to prevent the body from using its own protein stores in muscles, tissues, and cells for energy. Thus the program is a "modified" fast.

Carbohydrates are usually the body's primary source of energy. Since a very limited amount of carbohydrates are consumed, fat becomes the primary fuel source for the body. This rapid breakdown of fat produces ketones that spill into the urine, called ketosis. Ketones in the urine are desirable. While in ketosis, most people lose their appetite, which is a benefit of this program. A large amount of the water in your body is stored with carbohydrates. Since carbohydrate intake is severely limited and storage is severely depleted, dehydration is a health concern. To compensate, adequate quantities of fluid, sodium, and prescription potassium are required each day. Eating foods that are not appropriate can stop ketosis, which not only means less weight reduction, but it can cause dangerous shifts in the body's fluid and electrolytes.

Behavior modification

You will be asked to change your eating habits. Throughout the program, new behaviors will be introduced to encourage healthy habits. Your serious effort is required to change old eating habits, which will help you reach and maintain your desired weight. Your physician or dietitian may recommend an appointment with a psychologist to assist with behavior modification.

Appointment schedule
Physician Schedule Dietitian Schedule
Initial appointment and assessment Visit 1: Initial evaluation and instruction
Follow-up appointments: Visit 2: 2 weeks later
Approximately every 2 months Visit 3: 2-3 weeks later
  Appointments every month for the rest of the program

Purpose of the appointment with the dietitian

  • Instruction and education
  • Answer questions
  • Monitor blood work
  • Review food record
  • Review supplement intake
  • Learn behavior modification techniques
  • Monitor weight loss
  • Solve problems and provide ideas for common concerns such as preparing food, eating out, and traveling while on the diet
  • Develop a program for long-term weight maintenance when goal weight is obtained


When your goal weight is achieved, protein and dietary supplement intake will gradually be reduced while carbohydrates are reintroduced. This "refeeding phase" is essential for long-term success. Principles of a well-balanced diet are implemented to design a long-term weight control program. You will see the dietitian every two weeks during the beginning of refeeding.


An exercise program will tone muscles and assist with weight reduction and total body fitness. Be sure to obtain physician approval before starting an exercise program. A daily exercise program is encouraged. Your dietitian can give some tips on how to get started. An exercise physiologist can set up a more individualized program, if desired.

Estimated costs

Costs will depend upon the length of the program and are subject to change. Check with your health insurance provider regarding coverage before scheduling an appointment. Costs will include: physician visits (ranging from $83 to $314); dietitian visits, based on time ($41 per 15 minutes); and lab fees for blood test (average, $300).

PSMF success

As with any diet, success results when an individual is willing to make lifestyle changes. Patients who have completed the PSMF have been successful with weight loss. They’ve successfully maintained weight loss with the refeeding process and implementation of behavior changes.

Contact information

There are guidelines regarding participation in this program. If you are interested in the Protein-Sparing Modified Fast, please contact any of the Cleveland Clinic Family Health Centers; or, for main campus appointments, contact the Endocrinology Department at Cleveland Clinic at 216.444.6568.

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Can't find the health information you’re looking for?

This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional written health information, please contact the Health Information Center at the Cleveland Clinic 216.444.3771 or toll-free 800.223.2273 extension 4-3771 or visit This document was last reviewed on: 1/15/2007...#11145