What is Optifast?
The Optifast diet originated in 1974 and is a medically supervised weight loss regime designed for those who are considered obese, which means being more than 50 pounds over their ideal body weight (1). The Optifast diet consists of an 18-week program that is aimed at those who struggle with their weight management.
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During the program, the Optifast participants will undergo a complete lifestyle evaluation and receive constant supervision from medical experts along the way. Each participant will receive a custom meal plan, which is mostly liquid, but will transition into more solid foods as the Optifast program comes to a close. In addition, every participant will also receive a full workout program specifically designed according to their needs.
Optifast claims guaranteed results, since the participants will only consume foods in the form of liquids and that the daily caloric intake of the individuals will be cut by more than 50% in most cases (2). To see how much truth is behind all of these claims, simply continue reading and find out if the Optifast diet is for you!
The Main Phases of Optifast
Here are the mandatory phases each participant must go through when deciding to attempt the Optifast program.
1. The Screening Phase
During the first phase of the Optifast program, participants will go through the required medical examination. Health physicians will perform various screenings and tests to see if the Optifast program could have any negative impact on the health of the participant. Optifast has a complex network of health experts, physicians, doctors, lab technicians, nurses, counselors, and psychologist.
2. The Intensive Level
The second phase of the Optifast program is called the Intensive Level which is mostly oriented to overly obese individuals who suffer from a body mass index of over 30. Although participants with a minimum of 27 (IBM) can also enter this phase as long as they truly struggle with weight management. Individuals who suffer from high blood pressure, high cholesterol levels, or indulge in nicotine and alcohol might experience some potential risks (3) (4).
3. The Active Weight Loss Level
In this phase, participants will finally experience some action. The Active Weight Loss Level usually lasts between four and six weeks and requires the participants to replace 1 to 2 meals per day with an Optifast recommended product. According to Optifast, you could lose up to 5lbs per week if you combine this phase with regular physical activity.
If the participant passes the medical screening, he will enter an active weight loss phase in which he will only consume Optifast shakes. Each individual will consume only around 800 calories per day (5).
4. The Transition Phase
Similar to the previous one, this phase also lasts four to six weeks depending on the individual. During the Transition Phase, patients won’t be drinking the Optifast shakes anymore. They will instead learn portion control, helping them gravitate towards smaller, healthier food options. All participants will be advised by Optifast nutritionists on a daily basis.
During this phase all individuals must follow these requirements:
- Eat 1 or 2 low-calorie meals during the day which would not exceed 400 calories
- Consume high fiber and low starch vegetables
- Include at least two servings of fruit per day, no more than 70 calories
- Consume only one serving of dairy each day that doesn’t exceed 100 calories.
5. The Maintenance Level
This is the last and toughest phase of the Optifast program. After successfully finishing the Optifast program, clients are strongly encouraged to keep track of their progress. With their new healthy habits, participants should maintain their weight loss results long-term.
However, if a client gets off track and simply stops eating healthy and exercising, the whole Optifast program is worthless (6).
1. Optifast Weight Loss Shakes
The Optifast low-calorie shakes are high in protein and fiber and were created to keep you fuller for longer periods of time. In order to prepare these shakes you only need water. They come in six delicious flavors, including chocolate, vanilla, strawberry, banana, coffee, and caramel.
2. Optifast Nutritional Bars
These high protein and fiber bars are ready to eat at any occasion. Optifast Nutritional Bars provide energy and nutritional value that lasts up to four hours. Optifast suggests consuming these Nutritional Bars as a meal replacement rather than a snack. Three flavors are available: chocolate, cappuccino, and berry crunch.
3. Optifast Soups
The Optifast Soups are available in packs of eight and one pack is meant to replace a meal. Optifast Soups are filled with protein and come in three different flavors: vegetable, chicken, and tomato.
4. Optifast Desserts
For all sweet eaters, the Optifast Dessert range will surely be a delight! Although, you have to prepare these desserts in advance and then cool them off in the fridge. This way you will receive the sweetest experience. Optifast Desserts are available in only two flavors: chocolate and lemon crème.
Does Optifast Actually Work?
Taking everything into consideration, Optifast will provide optimal results. Most users reported significant weight loss in a relatively short period of time. However, once the Optifast program has been completed, the dieters are left to maintain their success on their own, and this is the main issue for most people, actually having enough discipline and courage to continue eating healthy and exercising. For this reason, Optifast most likely won’t satisfy your long-term weight loss goals (7).
The Cost of Optifast
Any time you see an offer for a medically supervised diet you can bet it’s expensive. The Optifast diet is no exception. The cost for the Optifast program alone is $2,100 for 18 weeks, in addition, you will also be required to spend another $115 per week on food and supplements. So by no means is Optifast a cheap nor easy way to lose weight.
Possible Optifast Side Effects
Optifast is a relatively safe program. However, there have been some negative experiences of this program (8). Here are some of the possible adverse effects you might face during the Optifast diet:
- Constipation or Diarrhea
- The sensation of hunger
- Some individuals might develop gallstones as a result of a rapid weight loss
Editor's Tip: After reading the conclusion about Optifast, please check out PhentaSlim to see why it is our #1 recommendation.
After reviewing all the necessary information, we can undoubtedly confirm that Optifast can provide incredible weight loss results. However, if you decide to go with Optifast some changes will have to be made to your lifestyle. Exercising and a strict diet plan will be your new way of living. Optifast is also going to cost you quite a bit of money.
Bottom line, if you’re truly prepared for a healthy lifestyle for the long-term, then you should definitely go with Optifast. On the other hand, if you’re only ready to commit halfway, you will only receive short-term results that will fade over time.
- “Overweight and Obesity as Public Health Problems in America.” Office of the Surgeon General (US) (2001). Viewed at: https://www.ncbi.nlm.nih.gov/books/NBK44210/
- Monica C Klempel, Cynthia M Kroeger, Surabhi Bhutani, John F Trepanowski, and Krista A Varady. “Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women.” Nutr J. (2012). Viewed at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3511220/
- J Audrain-McGovern and NL Benowitz. “Cigarette Smoking, Nicotine, and Body Weight.” Clin Pharmacol Ther. (2011 Jul). Viewed at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3195407/
- Lu Wang, MD, PhD, I-Min Lee, MBBS, ScD, JoAnn E. Manson, MD, DrPH, Julie E. Buring, ScD, and Howard D. Sesso, ScD, MPH. “Alcohol Consumption, Weight Gain, and Risk of Becoming Overweight in Middle-aged and Older Women.” Arch Intern Med. (2010 Mar 8). Viewed at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2837522/
- Kimberly A. Gudzune, Ruchi S. Doshi, Ambereen K. Mehta, Zoobia W. Chaudhry, David K. Jacobs, Rachit M. Vakil, Clare J. Lee, Sara N. Bleich, and Jeanne M. Clark. “Efficacy of commercial weight loss programs: an updated systematic review.” Ann Intern Med. (2015 Apr 7). Viewed at:
- Luca Montesi, Marwan El Ghoch, Lucia Brodosi, Simona Calugi, Giulio Marchesini, and Riccardo Dalle Grave. “Long-term weight loss maintenance for obesity: a multidisciplinary approach.” Diabetes Metab Syndr Obes. (2016). Viewed at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4777230/
- Christopher N. Ochner, Dulce M. Barrios, Clement D. Lee, and F. Xavier Pi-Sunyer. “Biological Mechanisms that Promote Weight Regain Following Weight Loss in Obese Humans.” Physiol Behav. (2013 Aug 15). Viewed at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3797148/
- Kirschner MA, Schneider G, Ertel NH, Gorman J. “An eight-year experience with a very-low-calorie formula diet for control of major obesity.” Int J Obes. (1988). Viewed at: https://www.ncbi.nlm.nih.gov/pubmed/3360564
Emily has spent the last 8 years comparing, reviewing and analyzing ingredients in the supplements industry. She has worked extensively with dieticians, nutritionists and personal trainers to separate fact from fiction and help people achieve their fitness goals. In her free time she works and enjoys the outdoors with her husband and 2 children.