Optifast (A.K.A. Optifast VLCD) Diet Review

Optifast (A.K.A. Optifast VLCD) Diet Review



Update: Dec 27, 2022

5.5 Out of 10
Optifast (A.K.A. Optifast VLCD) Diet Review
Optifast (A.K.A. Optifast VLCD) Diet Review
  • Encourages healthy ways of living
  • Meal prep is kept to a minimum with meal replacements
  • Offers support and accountability on a regular basis

Founded in 1974 by the Novartis Medical Nutrition Corporation, Optifast is a liquid-based diet marketed to people who need to lose a significant amount of weight, and it is best known to people who are gearing up for gastric bypass surgery. With that being said, this program is not for everyone, as it recommends doctor supervision and weekly counseling sessions.

The bulk of their business comes from meal replacement shakes, yet they offer a variety of other products such as vitamins, soups, bars, and fiber replacement pills. The customer service representative was friendly, but could only give me so much information because this program requires medical supervision to even become qualified to join the program. I could not find this company name under the Better Business Bureau registered businesses.

How Does It Work?

3 Phases of Optifast

3 Phases of Optifast was designed for people whose health have been impacted by excessive weight.

People may be able to lose weight quickly with the help of the Optifast weight management system. There are different age groups and programs made just for people going through some weight loss treatments. During the main phase of any of the Optifast diets, which can last more than six weeks, dieters must eat mostly Optifast foods.

The three phases of Optifast are:

  • Active weight loss
  • Transition
  • Maintenance

The person goes to the clinic, where the doctor does tests and makes a personalized plan. During the Active Weight Loss Phase, you’ll eat Optifast meals instead of all your regular meals.

Active 2: During this phase, you’ll eat and drink:

  • 3 VLCD products from OPTIFAST
  • 2 cups of low-starch vegetables
  • 1 teaspoon of vegetable oil
  • 800 calories per day

In 1983, scientists found that diets with 800 calories or less were safe. Still, the Annals of Internal Medicine say that weight maintenance is a problem that needs to be dealt with after goals are met or when the dieter goes back to eating more calories.

In 2017, research shows that the same things are true. This time, the results were published in the European Review of Medical and Pharmacological Sciences. The authors said, “Our results show the efficacy of VLCKD with synthetic amino acidic protein replacement, for the reduction of cardiovascular risk, without the development of sarcopenia and activation of inflammatory and oxidative processes.” In this case, the diet was ketogenic, so there weren’t many carbs. This shows that 800-calorie diets can be done safely, but how well do they work for long-term weight loss?

In 2014, the International Journal of Clinical Practice published an article about the results of a three-year survey to “find out what a very low-calorie diet (VLCD) does.” The study found that people who lost weight were able to keep it off as long as they kept up with “group-based behavior therapy on weight loss and long-term weight management.”

According to the Journal of Gerontology, there is even research that shows a VLCD can help older people who are obese lose weight.

About 12 weeks pass during this phase. But you’ll be checked on every week. The group meeting once a week is another benefit.


The transition phase is the second phase, which is also called the Active 1 Phase. It lasts about six weeks, and then you slowly start to eat normal foods again. You’ll continue to attend group sessions.

During this stage, you will eat:

  • 1 Product from Optifast VLCD
  • Two meals with few calories (approximately 400 calories each)
  • at least 2 cups of vegetables with few or no starches
  • Two fruit servings
  • One serving of milk,
  • 1,000 to 1,200 calories per day

Long-Term Weight Management

All of the Optifast VLCD products are taken away from the Maintenance Level, and the focus is on keeping the weight off.

The food intake is made up of:

  • Three meals with few calories (approximately 400 calories each)
  • Two fruit servings
  • One serving of dairy and vegetables with few starches.

The person on the diet works out and sticks to the good eating habits they learned during the program. Dieters eat regular food and Optifast meal replacements, and one of the benefits is that Optifast is always there to help.

Scroll down to find out about one of the best things we’ve seen in the last year.

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Optifast Shake Ingredients

Optifast Ingredients

Over 20 extra ingredients are added to OPTIFAST products, such as oils, proteins, natural flavors, sweeteners, and flavor and texture enhancers.

Optifast sells many different things. The Optifast Method, on the other hand, relies more on meal replacement shakes than on other pre-packaged foods. Some of the things in Optifast are:

  • Concentrate of milk protein
  • Soy Protein Isolate Maltodextrin Vitamin Minerals
  • Concentrate of milk protein

There are different milk-based protein powders that can be used in Optifast shakes, but research suggests that milk protein concentrate may not be the best choice. According to a study published in the Journal of Food Science and Technology in 2017, milk protein concentrate is hard to dissolve. Protein powders can make your mouth feel grainy if they aren’t dissolved well.

Isolated Soy Protein

“Soyfoods have been known for a long time to be good sources of high-quality protein and healthy fat,” says the journal Nutrients. Soy has also been shown to help with things like mood and skin health, as well as more serious health problems. Some people have worried about the safety of isoflavone use because it might have hormone-like effects. However, authors say that reports of side effects are mostly from studies on animals, while studies on humans support the safety and benefits of soyfoods.


“Maltodextrins (MDs) are a type of carbohydrate (CHO) that can be made from a variety of plants. “They are made in factories by breaking down the starch with enzymes or acids, then cleaning it and spray drying it,” says Critical Reviews in Food Science and Nutrition. There are two kinds of maltodextrin: one that is easy to digest and one that is not so easy to digest. We don’t know which one is in Optifast shakes because we don’t know what they are.

If maltodextrin is added as a fiber source or prebiotic, which would be good, it could change the way this product works.

Vitamins and Minerals

If you take a multivitamin in the morning, you might be worried about taking one that has even more vitamins and minerals. But these are put in meal replacement shakes to make them taste like the vitamins and minerals in whole foods. There’s no way to completely replace what’s missing, so a standard amount is usually added.

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Scientific Studies

The OPTIWIN study is a 52-week, randomized, controlled clinical trial with an open label that looked at how safe and effective the Optifast weight-management program was.

In the OPTIWIN study, 135 people in the Optifast group followed a plan that replaced all of their meals for 16 weeks. 40% of the meals were carbs, 40% were protein, and 20% were fat. After 16 weeks, traditional foods were added slowly.

The food-based group had 137 people who ate a low-calorie diet that followed the rules of the Diabetes Prevention Program.

Each week, both groups worked out hard for 150–180 minutes. They also went to sessions of behavior counseling.

The group that did Optifast lost twice as much weight as the group that ate food. The Optifast group lost an average of 12.4% of their weight, while the food-based group lost an average of 6.0%. The people who did Optifast lost more fat mass (30%-64% vs. 12%-42% of fat mass) and waist circumference (p=0.011 vs. p=0.0011).

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Will Dieters Lose Weight With Optifast?

This program is once again not for everyone, as the patient will need to be under medical supervision due to a very restrictive diet. In the long term, I would not put my faith in Optifast as a fix for weight problems, but it can get you to lose some weight initially.*

This is a short-term solution to a lifelong journey of finding a healthy body. It is pricey, and one can spend nearly $2,500+, depending on the clinic with Optifast.* Any time a large amount of weight is lost in a short period of time, there are going to be certain risks.

Due to the constraints of a low-calorie diet, there have been side effects reported.* Many first time users have been said to feel light-headed, and hungry as this is obvious when starting a program such as this.

Optifast is not like other ways of losing weight. It’s great for some people, but hard for others. The Optifast diet limits the number of calories you can eat. Even though this may help you lose weight, some people find it hard to eat so few calories.

Assuming a person is ready to start the program and can find a clinic nearby, the diet is still very intense and will require a lot of time off work or school for medical appointments. This could also stop people from being successful and make them give up in the middle. Some of the things that are used to make Optifast products are also not clear.

They might not stop the person from losing weight, which is the main goal of the program. Maybe the best way to find out if Optifast works is to look at what other people have said about it.

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What Users Are Saying?

Optifast customer testimonials

Some of Optfast’s customer testimonials

Shakes that taste great. I think they have the best texture and dissolve the best out of all the meal replacement shakes on the market (thick shake sort of texture). The only bad thing is that they cost a lot! $60 for 18 shakes. – Hellen H.

I don’t understand how this shake can take the place of three meals. I’ve now tried all of them, and they’re all awful. Even with low-fat milk, I tried one and it was still awful. I now add fruit to my shake so I can drink it. But I’m hungry again in about an hour. – Cory P.

Hi, I’m currently drinking the vlcd chocolate Opti-Fast shakes. They don’t taste too bad, but some pharmacies charge a lot for them. The shakes do make me feel full, which is good. Overall, this product is pretty good in terms of price, taste, and variety, but chocolate is my favorite. – Josh C.

I bought a packet of Vanilla so that I could eat it instead of breakfast sometimes. I have diabetes, so I thought this could be a good choice. Wrong! It tasted bad and made my blood sugar go up. Also, the sickly sweet taste made me feel sick for a couple of hours. I’ll just have a piece of low-carb multigrain toast and a cup of coffee, please. – Julia R.

I like all of them except strawberries, but I’d still buy strawberries if I had to. I don’t like the soups, but I love both the chocolate and lemon desserts. I think it has just enough sugar to stop me from wanting more. When I asked my doctor about Optifast, she said it’s perfect and has all the vitamins I need. Karen D.

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Is Optifast Easy To Follow?

No. Many people who start Optifast have a long road ahead of them. Many times, the patient’s need to drop weight in order to get ready for a gastric bypass surgery (which also has its separate recovery and health processes).

When taking Optifast, you are drinking their shakes for breakfast, lunch, and dinner. You are required to follow a complete liquid diet. This is not an easy process, as many people experience severe withdrawal symptoms, and it can also affect them mentally.*

Because this is such a drastic program, a doctor has to supervise you weekly. The timeframe can vary from person to person, depending on how long they need to stay on Optifast, and it can be life and death for some of the patients.

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Is Optifast Safe?

Optifast diet safety

Safety precautions of Optifast diet

Since this program is completely medically supervised, there is a screening process to figure out who would be the best fit for it.

Still, there are a few things about the OPTIFAST program that could be dangerous.

OPTIFAST is made for young adults and older people. People under the age of 13 should not use it.

First, the diet part is hard, especially in the first active phase.

Even for people who have never had an eating disorder before, labeling foods as “good” or “bad” can lead to a bad relationship with food and disordered eating habits.

People who are pregnant, nursing, or athletes should not follow this program. This is because the diet is too limited to provide enough calories and energy, especially when it comes to carbs.

The OPTIFAST products are also not good for people who are allergic to or can’t eat dairy or soy.

If you take medicine for blood sugar, your dose may need to be changed while you are on this program. Your health care provider will work with you and, if necessary, suggest changes.

If you are thinking about taking OPTIFAST, you should first talk to your primary care doctor about the pros and cons.

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Optifast Side Effects

The Optifast diet plans may be more helpful than other diet plans in many ways. Dieters on Optifast are more likely to stay on track and avoid any risks that come with losing weight if they talk to their doctor, psychologist, and dietitian often. But there are some things that could go wrong when someone starts a diet like this:

  • In women, the formation of gallstones can result from rapid weight loss.
  • Nausea
  • Diarrhea
  • Constipation
  • Fatigue
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How Much Does Optifast Cost?

Optifast usually costs around $150 per week. The generic answer would be that it varies based on which clinic you attend and which program they assign to you. However, most clients end up being on the program for at least 18-26 weeks which equates to about $2,700-$3,900 total.

Also, the price changes based on what the person wants. But some people think that Optifast products are too expensive. If you want to know more about the price, you can talk to the company directly.

You can enter your zip code on their website to find a clinic near you. You might be able to find out more about possible costs there.

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Bottom Line: Is Optifast a Rip-Off or Worth to Try?

Obviously, this program is not for everyone. It can be an intense process of simply drinking liquid for months at a time.*

You can’t just order the product online and have it shipped to your home without a consultation first. This is a completely different diet program than most, and needs to be reviewed with a different mindset.

Their Facebook community is rather small and unsupportive. The last post was nearly one year ago with hardly any community activity. To sum it all up, this is not a program to merely experiment with, as many people are using Optifast to save their lives from obesity.

5.5 Total Score
Optifast Scorecard

  • Encourages healthy ways of living
  • Meal prep is kept to a minimum with meal replacements
  • Offers support and accountability on a regular basis
  • Very low in calories
  • Many customers report poor taste of products
  • Diet is limited to meal replacements in the first few months
User Rating: No Ratings Yet!
  1. Help…? I am 100 lbs overweight and desperate to lose. However, I do not want to do surgery unless I feel like I have nothing left in me to fight anymore. It is a daily struggle, but I believe it can be done. I would like to try Optifast but it seems there is a vast difference between the 800 & the 900, and that a doctor’s supervision is required. Apart from Brenda whose son was on the diet without the surgery, has anyone else tried this product without the surgery? Looking for any assistance anyone can offer. Many thanks.

  2. Been a tad over 2 months for me, at my half way point on my shakes. I am using half old formula and half new formula to cut sugar way back. I have lost as of today 40 pounds in 2 months THAT IS HUGE I need to lose another 35 and Im done!! I have thinning hair too, and looked up the vitamins needed to curb that. Hoping it works. I use Sugar free Jello if get hungry, even sneak in some Trader Joes Organic low sodium chix broth helps when I get really hungry. I do water walking in my pool 3-5 x a week. This diet is NOT for the weak for sure. BUT SO easy, no shopping or cooking or cleaning, I use my Ninji bullet and rinse it and put it back in fridge. I use coffee with my chocolate shake and sugar free root beer syrup in my vanilla shake, Strawberry, I add banana extract. So many things you can do with extracts or sugar free things, Best of luck you all.

  3. Reply
    Cheryl Mercer Campbell July 17, 2019 at 11:50 am

    I started the Optifast program two weeks ago today. Not finding a lot of current information or support groups on the internet. Lost 10.4 the first week and will be getting weighed again later today.

  4. Reply
    Gilbert Desgranges July 17, 2019 at 12:46 pm

    I have lost 103.5 pounds on the Optifast 900 program under the supervision of my family doctor, the program doctor and, many wonderful people working within the program(support, dietician, nutririonist, psychologist, etc). went from a 54 waist to 35 waist. I looked really funny wearing baggy pants and constantly making holes in my belt!!! It took about 3 1/2 months(Aug – Dec and yes through the Holidays!) however please note i was on the Optifast 900 and NOT on the Optifast 800. That meant 4 shakes of 225 calories each per day. Daily 2 hour walks and the program worked wonders! I had no real difficulties but I must say I was determined like no other!! I never once deviated from the program even refusing free samples of chocolate, candy, foods at various Trade shows, Costsco, etc. I did not even mind the hair loss, the constant feeling of being cold and having to get a completely new wardrobe. That was in 2011. I kept it off until I stopped writing my daily journal. I thought I could do without it as I knew all the calories in everything I was eating. Imperceptibly, the portions started increasing and 5 years later I have gained 60 Lbs. I am writing this so you know that the program does work however there is a requirement to “keep it up” through portion control and daily walks (not necessarilly exercise unless you want to) and keeping up with the good habits developped throughout the weight loss phase. I have started again to be careful and although I am limited in so far as walks go (I am caring for an aging aunt 24/7) I do my best to go up and down the stairs many times a day and I will be on the stationary bike an hour at least per day bike as soon as I get it; it is on it’s way.

  5. I was so tired of eating and needed a break. The liquid part of this diet was the easiest thing I ever did. After the first few weeks, I felt great, had tons of energy and really enjoyed the diet. I added calorie free flavored syrups to my shakes such as peanut butter banana, caremel, coffee and many more. Did nothing but liquid for 4 months and loved it. I lost 110 lbs in 9 months. Unfortunately, if you don’t do the diet correctly, there is a big chance of developeing gallstones where I ended up having to have my gallbladder removed.

  6. Over the past 3 months I have put on a huge amount of weight do to an accident (elbow reconstruction) leaving me unable to exercise for a couple of months and still with a huge amount of restrictions on what Im allowed to do. Im male, 1.74m tall and before I started the Optifast diet I weighed 93kg.

    I’ve been on Optifast just over 2 weeks ago with a daily plan of 3 meals which consist of shake for breakfast, shake or bar for lunch with low carb vegetables 1 cup (so no potatoes, peas etc) and dinner consisting of shake plus 2 to 3 cups of vegetables (low carb) and about 1.5 to 2lt water daily. And importantly, no carbs.

    After the first couple of days of withdrawal (potato and bread the hardest to give up), some headaches and irritable stomach things settled down and Im now enjoying the vegetable diet with the shakes. Don’t feel overly hungry and have good energy levels. Im getting to the gym 3 days a week for an hour on the treadmill (mix jogging/walking) and have so far lost 5.3kg which im rally happy with.

    My plan is to lose a further 10kg to bring my total weight down to a respectable 78kg. Im expecting to hit that weight sometime in December.

    After that, I will move to a keto based approach to eating going forward with some intermittent fasting that I hope will keep me in the 78 to 80kg range. Naturally, I will be bringing back into my life alcohol (wine primarily) and occasional carbs (yep bread and potato) but in strict moderation…

    Do I think Optifast is worth it… For me, yes… Im not bothered about the support groups as its obvious to me that I need to drop the weight to get healthy and for future quality of life!

    Good luck on your own personal weight loss journey!

  7. Not an easy diet but I am in early days myself.
    In 2 weeks I am down 10 lbs. no exercise. It is simple to prep the shakes and as others have said once you find a way to make them palatable then you are on your way.
    You need extremely strong will power as there is no sense deviating from the plan (I am on optifast900 in Canada under MD supervision).

    Facebook groups are more active than others, if you’re looking for support.

  8. I am enjoying phase 2 as my Dr suggested this it’s only week one but I’m down 4.3kg so I’m happy with that.Plus optifast suppresses my hunger & I needed this to start me journey now my head is in a lot better place now. I have a lot of weight to lose but small steps no hurrying for this looking forward for in a years time I just want to be healthy and happy & smaller dress sizes so off I go ????????????

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