What is OPTIFAST® weight loss program?

The OPTIFAST® weight loss program is a medical weight loss program designed to help overweight and obese patients lose weight safely without surgical intervention. The program succeeds because it treats the whole you – not just your weight. The program utilizes a partial meal replacement plan that transitions to self-prepared “everyday” meals, in conjunction with comprehensive patient education and support.

How does the OPTIFAST® weight loss program work?

The OPTIFAST® weight loss program is a supervised 18-week program that starts with a liquid-only diet.  As you move through the program, solid foods will be gradually introduced. 

While participating in the OPTIFAST® weight loss program, you’ll be closely monitored and given the support, counseling, lifestyle education and meal replacements to help you enjoy long-term weight loss and significantly reduce weight-related health risks.  

Program components include:

Meal replacement diet 

Narrowing your food choices helps you work towards weight loss and management by controlling the amount and types of food you eat. Positive change can occur quickly. In addition to losing weight, you will improve your health, learn new, healthier eating habits and engage in activities so that when you return to self-prepared foods, you are better equipped to manage your weight long term.

Medical supervision

Utilizes the expertise of medical professionals to help you lose weight safely. More and more, clinical studies suggest medically-monitored, weight-management programs are safe, effective and help individuals address and modify behaviors to encourage long-term weight management.

Lifestyle education 

Helps you achieve and sustain better health through nutrition, exercise and lifestyle changes.


Individual and group counseling by experts who understand your challenges.

Ongoing personalized support 

Included both during and after weight loss to help you achieve and maintain success.
Programs are designed specifically for each patient and their needs.

Who is a candidate for OPTIFAST® weight loss program?

OPTIFAST® weight loss program is designed for patients who:

  • Have a BMI of 30 or more or struggle with a BMI of 27 or more and have another condition such as Type 2 diabetes, hypertension and high cholesterol or sleep apnea
  • Want support overcoming emotional barriers to weight loss
  • Appreciate the supervision of a physician, along with a comprehensive health care team

Benefits of OPTIFAST® weight loss program

Patients often lose weight quickly in the OPTIFAST® weight loss program. Follow-up studies at five years showed over 45 percent of patients kept enough weight off to improve their health long term. After two years, 40 percent of patients maintained more than half their weight loss; 78 percent of men and 60 percent of women maintained medically significant weight loss.

Disadvantages of OPTIFAST® weight loss program

Patients often gain weight back after the program has been completed. Early in the program, patients are monitored closely to ensure they are following the program. Once patients have completed the program, it is harder for them to maintain the healthy habits. 

Many obese patients have a hard time following this program because the lifestyle changes are made so quickly and are so drastic it is hard for the patient to be compliant. 

The OPTIFAST® Weight Loss program experts recognize that a key to successful weight management is periodic or continuous involvement in a weight management program.

Patient Journey

Once you begin the OPTIFAST® Weight Loss Program, you’ll progress through the three program phases

Active Weight Loss Phase

During the 16-week Active Weight Loss phase, you’ll use an OPTIFAST® Weight Loss program partial meal replacement diet and receive monthly medical monitoring. In addition, you’ll be encouraged to attend monthly group sessions under the care of a behaviorist, registered dietitian and/or exercise specialist.

Transition Phase

During the Transition Phase, you’ll transition to regular foods, continue to participate in group sessions and meet with a dietitian each visit.

Long-Term Weight Management Phase

The Long-Term Weight Management Phase is ongoing and can include partial OPTIFAST® Weight Loss program meal replacement and partial regular food, as well as ongoing support.

Keys to success with OPTIFAST® weight loss program

Weight management is an ongoing process that requires intermittent behavioral, nutrition and exercise intervention. It is important to know that relapse is not unusual. But being persistent in your journey is the key.

Mercy Health offers a variety of tools and staff support during the active weight loss and transition stages as well as monitoring for long-term weight management.

Find a weight loss specialist nearby

Mercy Health locations that can treat you