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OPTIFAST Review: Does It Work for Weight Loss?

By Melissa Mitri, MS, RD

Medically Reviewed by Ana Reisdorf, MS, RD

Published on February 5, 2022

Dietitian Rating:

3.0

About This Rating
The average rating of this product is calculated based on the evaluation of the following factors:
  • Evidence-Based:3.5
  • Easy to Follow:2.0
  • Customization:2.5
  • Sustainability:2.0
  • Accountability:5.0
  • Value for the Price:3.0
  • Safety:3.0

OPTIFAST is a medically supervised weight-loss program incorporating nutrition, exercise, and behavior modifications. It may help you lose weight, but the weight may creep back up over time.

Written by
Melissa Mitri, MS, RD
Registered Dietitian Nutritionist
Melissa Mitri, MS, RD, is a registered dietitian nutritionist, weight loss specialist, and expert health writer with over 15 years of experience in the health and wellness industry. Melissa has worked in a variety of healthcare settings helping clients improve their diet through an individualized approach.
Medically Reviewed by
Ana Reisdorf, MS, RD
Registered Dietitian Nutritionist
Ana Reisdorf is a registered dietitian nutritionist with 14 years of experience in the field of nutrition and dietetics. She graduated from UCLA in 2002 with a degree in psychology and women’s studies and completed her master’s degree from Central Michigan University in 2010
OPTIFAST Review: Does It Work for Weight Loss?
Photo credit: iStock.com/PixelsEffect

Pros

  • Promotes healthy lifestyle habits
  • Minimal meal prep with meal replacements
  • Offers frequent accountability and support

Cons

  • Very low in calories
  • Many customers report poor taste of products
  • Diet is limited to meal replacements in the first few months

What Is OPTIFAST?

OPTIFAST is a multidisciplinary weight-loss program that incorporates nutrition, exercise, and lifestyle education components to help you lose weight and improve your health.

It is designed for those with a BMI over 30, or over 28 with co-existing weight-related conditions. It is completed over the course of 26 weeks.

The OPTIFAST program is owned by Nestle Health and is one of the original physician-supervised weight-loss programs. It has been around for close to 40 years, and was founded by three physicians at Mount Sinai hospital in Cleveland, Ohio.

Since its inception, the OPTIFAST program has evolved to be more comprehensive and provide a wider arsenal of food product offerings than the original liquid-only program.

Today’s OPTIFAST program remains medically supervised by Board Certified physicians.

The program involves 6 core components, which can be conducted in person or online.

  1. Medical Monitoring: An initial medical evaluation and lab tests are conducted. A personalized plan is then created along with regular medical monitoring.
  2. Nutrition Education: Regular nutrition education is provided on mindful eating, emotional eating, meal planning, eating out, and shopping and cooking healthier.
  3. Exercise Guidance: Exercise tips and recommendations are included in the regular nutrition and lifestyle education series.
  4. Patient Support: Personalized support, weight-loss guidance, and education are offered. Educational materials and handouts are also provided.
  5. Full Meal Replacements: Complete nutrition products such as shakes, soups, and bars are provided to keep your calories in check and promote weight loss.
  6. Lifestyle Education: A regular educational series is provided on lifestyle topics such as stress management and handling complex food issues and emotions.

You begin the process by finding a local OPTIFAST clinic near you and attending a complimentary introductory presentation about the program.

If you decide to try the program after the introductory session, you will schedule your initial medical visit to discuss your health history and goals. A personalized plan is then created for you.

How It Works

The OPTIFAST program is broken up into three key phases, which are intended to be completed in about 26 weeks.

The program is the most restrictive in the first phase, where your diet mainly consists of OPTIFAST meal replacements, and then over time, you slowly reintroduce regular foods.

  • Phase 1: Active Weight Loss Phase (1–4 months). During this phase, your diet will entirely consist of OPTIFAST meal replacement products. You will be consuming only around 800 calories per day, broken up into 4 or 5 meal replacements.

  • Phase 2: Transition Phase (4–6 months). During this phase, you gradually start to reintroduce regular self-prepared foods back into the diet. You are also encouraged to attend regular classes at this time to help change the way you think and approach eating.

  • Phase 3: Maintenance Phase (6–24 months). During this last phase of the program, you are eating even more regular food and are encouraged to continue attending ongoing support sessions to help you maintain weight loss.

  • Phase 4: Stabilization (26 months and after). This is a final phase of the program not posted on OPTIFAST’s main website, which I was able to find on the Nestle Health Website. During this phase, you eliminate all OPTIFAST products and consume all of your meals from regular foods.

Throughout each phase, you participate in one-on-one and group sessions to keep you motivated and on track.

You can expect to meet regularly with health professionals such as a medical doctor, registered dietitian, and a lifestyle counselor to check in. During these appointments, you will discuss your diet, exercise, and lifestyle goals to keep you moving forward.

Group education sessions and discussions are also held, where you can receive peer support from other OPTIFAST participants.

Lastly, educational materials are provided to help you put what you learn into practice.

OPTIFAST’s Scorecard

OPTIFAST was objectively evaluated by a dietitian based on the following criteria:

Evidence-Based: 3.5/5
Easy to Follow: 2/5
Customization: 2.5/5
Sustainability: 2/5
Accountability: 5/5
Value for the Price: 3/5
Safety: 3/5
Overall Rating: 3.0/5

Frequently Asked Questions

What is OPTIFAST?

OPTIFAST is a medically supervised weight-loss program that incorporates nutrition, exercise, and behavioral components to achieve lasting weight loss.

Do I have to buy the OPTIFAST meal replacements?

Yes, you are required to use the meal replacements as your sole source of nutrition during the initial active phase, which lasts 1–4 months.

After that, you are still required to consume the meal replacements at some meals, for up to 6 months.

How do the OPTIFAST meal replacements taste?

Customers report that the shakes and bars taste good, but the soup mixes do not. Users suggest eating the soup right away after it’s made for the best taste and consistency.

How long is the OPTIFAST program?

The program typically lasts up to 26 weeks and is broken up into active, transition, and maintenance phases.

How much weight can I lose on OPTIFAST?

The average weight loss is 30 lbs in 26 weeks on the program, according to OPTIFAST’s signature OPTIWIN study. (1)

How do I keep the weight off after I complete the OPTIFAST program?

You will increase your chances of keeping the weight off by continuing to watch your calorie intake, staying active, and practicing the healthy lifestyle habits taught throughout the program.

What You Can and Can’t Eat

The OPTIFAST program is considered a very low-calorie diet (VLCD) program. A very low-calorie diet is typically less than 800 calories a day but is high in protein and essential nutrients for health. (2)

The OPTIFAST diet is designed to put your body into ketosis.

Ketosis is when your body burns fat for energy instead of carbs, which typically occurs on a very low-carb diet and produces an initial rapid weight loss.

The diet portion of the program is broken up into three key phases and includes recommendations during a final 4th stage once you complete the program.

Here are the calorie details on each phase of the program and what you can and can’t eat on each:

Phase 1 (600–800 Calories Per Day)

This phase is designed to be your initial jumpstart for fast weight loss.

Depending on your goals and how much weight you need to lose, you will remain in this phase anywhere between 1–4 months.

During this phase, you’re only allowed to eat OPTIFAST meal replacement products (3–5 times per day), such as shakes, soups, and bars. The frequency of eating depends on your preferences and your overall calorie needs.

These products are high in protein and contain 24 essential vitamins and minerals.

There are no other outside foods allowed in this phase.

Phase 2 (800–1,000 Calories Per Day)

During this phase, most of your meals still consist of OPTIFAST products, but you start to reintroduce some regular foods back.

  • Meals 1 and 2: OPTIFAST meal replacement
  • Meal 3: Low-calorie meal, around 400 calories

You are also allowed the following:

  • 2 cups of low-starch vegetables (most vegetables except for green peas, legumes, lentils, corn, pumpkin, squash, and potato)
  • 1 serving of fruit
  • 1 serving of dairy

Phase 3 (1,000–1,200 Calories Per Day)

During this phase, you start to eat regular foods even more often and are only having OPTIFAST products once a day.

  • Meal 1: OPTIFAST meal replacement
  • Meals 2 and 3: 400-calorie meal

You are also allowed the following:

  • 2 cups of low-starch vegetables
  • 2 servings of fruit
  • 1 serving of dairy

Phase 4 (1,200–1,500 Calories Per Day)

During this phase, all OPTIFAST products are eliminated and you are advised to consume all of your meals from regular foods.

This phase is designed to help you maintain weight loss long-term.

  • Meal 1: 400 calories
  • Meal 2: 400 calories
  • Meal 3: 400 calories

You are also still allowed:

  • 2 cups of low-starch vegetables
  • 2 servings of fruit
  • 1 serving of dairy.

Water and Beverages

You are encouraged to drink 2 liters of water every day throughout the entire program.

Sugary beverages like juice and soda, as well as alcohol, are not allowed.

Summary

OPTIFAST is a high-protein, low-carb meal replacement program that is the most strict in the beginning and then gradually allows more foods. You are required to restrict starchy vegetables, fruits, and fruit juices.

OPTIFAST Meal Replacements

The OPTIFAST program offers low-calorie meal replacement shakes, bars, and soup mixes that are a core component of the first and second phases of the program.

All products are considered low-calorie, high-protein, and low-carb. They are classified as a complete meal, part of a medically supervised program.

In the first phase of the program, you are only eating these meal replacements. Since they are all 200 calories or less, it makes sense that you would lose weight during this first phase.

They are also high in protein and contain a good amount of fiber. Both fiber and protein help to keep you full, especially following a low-calorie diet.

Shakes

There are both shake mixes and ready-to-drink shakes available. The shake mix packets can be mixed with 8–10 ounces of cold water, while the ready-to-drink shakes are convenient for on-the-go.

OPTIFAST Shake Mix 

Available in chocolate and vanilla flavors. These are OPTIFAST’s regular shake mixes.

  • Calories: 160
  • Protein: 16 grams
  • Carbs: 18 grams
  • Added Sugar: 4 grams
  • Fiber: 3 grams

OPTIFAST HP (High Protein) Shake Mix 

Available in chocolate, strawberry, and vanilla. These are a higher protein version of their shake mix and may be better for someone more active with higher protein needs.

  • Calories: 200
  • Protein: 26 grams
  • Carbs: 11 grams
  • Added Sugar: 6 grams
  • Fiber: 0 grams

OPTIFAST Ready to Drink Shakes (Regular and HP)

The nutritional facts for these premade shakes are the same as for the regular and high-protein shake mixes above.

Bars

These are another meal replacement option. They are available in chocolate, apple cinnamon, and peanut butter chocolate flavors.

  • Calories: 160
  • Protein: 16 grams
  • Carbs: 17 grams
  • Added Sugar: 4 grams
  • Fiber: 4 grams

Soups Mixes

Dried packets of tomato, vegetable, and chicken soup are available and can be mixed with 8–10 ounces of hot water. The nutrition facts are the same for all three soups.

  • Calories: 160
  • Protein: 16 grams
  • Carbs: 18 grams
  • Added Sugar: 4 grams
  • Fiber: 4 grams

Ingredients

OPTIFAST products contain over 20 added ingredients, including oils, proteins, natural flavors, sweeteners, and additives for flavor and texture. Most of the ingredients are fairly safe, but they are not allergen-friendly.

The added sugar is kept low, which is a good thing as it may contribute to weight gain. However, artificial sweeteners such as sucralose (i.e., Splenda) are present in all the products. (3)

Even though sucralose is calorie-free, it is extremely sweet-tasting, and some reports suspect too much of it can increase cravings for sweets.

Too many artificial sweeteners like sucralose may also negatively affect your gut health, which may also play a role in regulating your weight. (4)

All OPTIFAST products contain dairy and soy ingredients, so they are not suitable for those with these allergies or intolerances.

Overall, the products they offer are decent, but they do not have a very large variety. Eating only these for four months can quickly get monotonous.

Summary

The OPTIFAST program provides meal replacement shakes, bars, and soup mixes to help you stay within your calorie goals. The variety of options is not huge, so it may get boring quickly.

Can It Help You Lose Weight?

OPTIFAST participants typically see an average weight loss of around 30 pounds during the 26 weeks of the program. But after the first year, many people start to see their weight slowly creep back up.

There are several links to research articles on the effectiveness of OPTIFAST on their website. However, every one of them is funded by Nestle Health, which owns the OPTIFAST program, which adds an element of bias.

Their signature study is called the OPTIWIN study. Based on the results of this study, the program claims you can expect to lose an average of 30 lb in 26 weeks of the program. (5)

This was twice the amount of weight loss compared to the other group following a traditional calorie-controlled food-based program.

At a little over a pound of weight loss per week, this is a healthy rate of weight loss. Based on the restrictiveness of the initial acute phase, the large majority of the weight loss is likely in the first few months of the program.

After one year, however, the amount of weight loss starts to diminish. On average, people maintained 25 lbs of weight loss after one year, 19 lbs after two years, and 15 lbs after three years.

The OPTIWIN study is the only randomized controlled trial done directly on OPTIFAST and involved 273 people. Randomized controlled trials are typically the gold standard of research study designs.

Another large observational study was done in 2018 involving participants who followed a medically supervised weight-loss program including OPTIFAST products. (6)

After five years, participants experienced a 5.8% weight loss on average, which is considered clinically significant.

There was no placebo group to compare to, however, so it’s unclear if there were also other factors leading to their weight loss. This study was also industry-funded, which means the results may be biased.

Low-carb, high-protein diets similar to OPTIFAST have been shown to be effective for weight loss, especially in the first 3–6 months. (7)

This may be because protein is highly satiating, which can help you more easily stick to a low-calorie diet. (8)

A very low-carb diet also brings your body into ketosis, reducing your appetite. Ketosis occurs when your body doesn’t have enough carbs to burn for energy, so it burns fat instead. (9)

This burning of fat creates compounds called ketones, which are then burned for fuel.

The question is whether you will maintain your weight loss on OPTIFAST after the first year, or if it will continue creeping back up.

The accountability and support provided while on the program can help keep you on track, but if you don’t continue practicing those same habits or following a calorie restriction, you may gain the weight back.

Summary

OPTIFAST can help you lose a significant amount of weight if you follow it properly. To lose weight long-term, you have to continue practicing the healthy habits you learned.

Sustainability

OPTIFAST can produce fast weight loss to give you a jump start; however, the low-calorie amount can be challenging for many to maintain for the length required.

Research has shown that diets below 1,200 calories a day, such as on OPTIFAST, can be difficult to sustain. They also increase the risk of yo-yo weight cycling and weight regain over time. (10, 11)

Most of my clients come to me for help after following very low-calorie diets (similar to OPTIFAST) and gaining the weight back.

I have seen this time and time again, and often the more times someone follows a restrictive diet, the harder it is to then lose weight again.

The initial active diet phase is probably the most challenging part to maintain, as it requires you to eat only their meal replacements for 1–4 months.

This can make it difficult to eat socially or go out to a restaurant, as you won’t be able to eat anything there, making you feel like you’re standing out.

While this level of restriction is only temporary, four months can definitely feel like a long time while you’re doing it.

If you can get through the first 6 months, it does get more manageable because you can start eating most foods again.

Staying fully engaged with the program, such as regularly attending one-on-one clinics and education sessions and actively asking questions, can help you stick to it.

Lastly, the program is also fairly costly, making it difficult to stay on long-term if you’re on a budget.

Summary

OPTIFAST is fairly restrictive, which may be difficult to sustain long-term. However, staying fully engaged with the program can help increase your likelihood of success.

Related: The 9 Best Diets for Sustainable Weight Loss

Accountability

There is a lot of support and accountability provided in OPTIFAST. This is probably one of the best parts of the program.

You are encouraged to attend regular one-on-one sessions at an OPTIFAST clinic or virtually with a medical doctor, registered dietitian, and lifestyle coach once a week during the initial active phase.

After that, you continue to meet regularly with staff throughout the program, but not as often.

There are also weekly educational sessions on nutrition, exercise, and behavior modification to teach you lifelong strategies to maintain weight loss.

Peer support groups are part of the program, where you can ask questions and share your own stories. When surrounded by like-minded people, it can make the process feel easier and hold you more accountable.

Summary

OPTIFAST offers virtual and in-person one-on-one and group accountability to keep you on track.

Cost

OPTIFAST does not disclose pricing on their website but states that it may vary by location, the clinic you attend, and the specific program that is created for you.

Based on consumer reviews and reports, the OPTIFAST program costs around $150 per week on average, including meal replacements. Most people follow the program up to 26 weeks, which would bring the total cost to around $3,900 for 6 months.

While this sounds like a big chunk of change, $150 a week is a fairly decent price for what you get. This total price bundles the cost of the meal replacements, health professional appointments, and educational sessions.

This price is an estimate, and you would find out the exact price after you attend your free one-hour initial consultation.

Most insurance plans do not cover the program, but some may offer partial reimbursement if you submit a receipt of payment.

If you have a medical spending account set aside through your employer, you may be able to use these pre-taxed dollars to cover some of the program’s expenses.

There is a 60-day money-back guarantee on all OPTIFAST products if you’re not satisfied with your purchase, less the shipping cost.

Regarding the OPTIFAST program itself, you are billed monthly and must cancel at least two weeks before your next billing cycle to avoid being charged.

Summary

OPTIFAST is a financial investment, but it bundles many features that would be more costly on its own.

Safety

Since this program is entirely medically supervised, there is a screening process to determine those who best qualify for the program.

Still, there are a few potential safety concerns regarding the OPTIFAST program.

OPTIFAST is designed for young adults and older people and is not recommended for those under 13 years old.

First, the diet portion is restrictive, especially in the first active phase.

Categorizing foods as being “good” or “bad” can trigger an unhealthy relationship with food and trigger disordered eating behaviors, even in those who don’t have a history of an eating disorder.

Those who are pregnant, lactating, or athletes should not follow this program. This is because the diet is too restrictive to provide adequate energy and calories, especially in regards to the carb content.

The OPTIFAST products are also not suitable for those with dairy or soy allergies or intolerances.

If you are taking blood sugar medication, your dose may need to be adjusted on this program. Your medical provider will work with you and recommend modifications if needed.

If you are considering OPTIFAST, we recommend speaking to your primary care doctor first to weigh the pros and cons.

Summary

OPTIFAST is a relatively safe program for most people as it is medically supervised. It is not suitable for those with an eating disorder, athletes, or who are pregnant or lactating.

How OPTIFAST Compares to Alternatives

OPTIFAST was one of the original medically supervised weight-loss programs.

The two programs most similar to OPTIFAST are Medi-Weightloss and Health Management Resources (HMR Program). All these programs are broken into three phases.

Medi-Weightloss is more similar to OPTIFAST in that it is medically supervised. Both of these programs employ highly trained professionals to provide support and guidance.

HMR is not medically supervised and instead employs health coaches to provide accountability. While health coaches can be supportive, they are not always trained professionals with credentials.

OPTIFAST and HMR both require you to consume their meal replacements for a set period of time. Their weekly cost is similar, but OPTIFAST is more trustworthy as they employ medical professionals.

Medi-Weightloss is more flexible as far as food choices and food cost, as you’re not required to purchase meal replacements.

The Bottom Line

OPTIFAST is a comprehensive weight loss program that addresses medical, diet, and lifestyle factors. It can help you lose a significant amount of weight if you are able to stick to the program long-term.

If you’re someone that thrives on structure and accountability, OPTIFAST may be a good weight loss program for you.

There is a lot of structure set up for you in regards to your meals and meal replacements, and you receive a lot of support and guidance from health professionals to keep you motivated.

However, if you want to eat real food, don’t want to feel restricted, and want more flexibility in a weight loss program, OPTIFAST may not be a good fit for you.

All in all, OPTIFAST can be an effective weight loss program if you are willing to adhere to it long-term.

If you decide to join OPTIFAST to lose weight, I would recommend staying fully engaged in the program and participating in regular one-on-one and group meetings.

This will provide accountability and can help keep you in the right mindset and on track towards your goals. (12)

I would also suggest utilizing all the available educational resources on diet, exercise, and lifestyle habits.

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At WellnessVerge, we only use primary references for our articles, including peer reviewed medical journals or well-respected academic institutions.

  1. Effectiveness of a Total Meal Replacement Program (OPTIFAST Program) on Weight Loss: Results from the OPTIWIN Study:
    https://pubmed.ncbi.nlm.nih.gov/30421863/
  2. Obesity: Identification, Assessment and Management of Overweight and Obesity in Children, Young People and Adults: Partial Update of CG43: Very-low-calorie diets:
    https://www.ncbi.nlm.nih.gov/books/NBK311324/
  3. Changes in Added Sugar Intake and Body Weight in a Cohort of Older Australians: A Secondary Analysis of the Blue Mountains Eye Study:
    https://www.frontiersin.org/articles/10.3389/fnut.2021.629815/full
  4. Artificial Sweeteners Negatively Regulate Pathogenic Characteristics of Two Model Gut Bacteria, E. coli and E. faecalis:
    https://www.mdpi.com/1422-0067/22/10/5228
  5. Effectiveness of a Total Meal Replacement Program (OPTIFAST Program) on Weight Loss: Results from the OPTIWIN Study:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587830/
  6. Real-World Effectiveness of a Medically Supervised Weight Management Program in a Large Integrated Health Care Delivery System: Five-Year Outcomes:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5798936/
  7. Relatively high-protein or 'low-carb' energy-restricted diets for body weight loss and body weight maintenance?:
    https://pubmed.ncbi.nlm.nih.gov/22935440/
  8. The role of protein in weight loss and maintenance:
    https://pubmed.ncbi.nlm.nih.gov/25926512/
  9. Impact of ketosis on appetite regulation-a review:
    https://pubmed.ncbi.nlm.nih.gov/32193016/
  10. Maintenance of lost weight and long-term management of obesity:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5764193/
  11. Consequences of Weight Cycling: An Increase in Disease Risk?:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4241770/
  12. The Assessment of Supportive Accountability in Adults Seeking Obesity Treatment: Psychometric Validation Study:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7420735/