Optislim vs Optifast: Discover Which Works Better

by Claire Huffman
Last Updated: 12/01/2021
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You started your diet on Monday, but tomorrow is Thursday and you already feel you’ve got no more ideas for further quick meal preparations. Not to mention that you’ve got millions of tasks and chores left unticked on your monthly to-do-list… So what do you do?

You either grab a coffee and a sweet, but stocked with calories, pastry during break hours or you may consider a pick-up-and-go meal replacement that will satisfy your hunger while assisting your weight-loss plan.

If you’re one of the many busy people who are looking forward to kick-starting weight loss by reducing calories, the Optislim and Optifast weight loss programs based on meal replacement shakes might be a good choice for you.

These dietary products are sold online, through retail shops or in health stores.

In order to fit the multitude of dietary needs and preferences, the meal supplement shakes of Optislim and Optifast contain a satisfactory amount of calories in a single take, fueled up with either protein, fibre as well as vitamins and minerals.

The most recognized product of the Optislim and the Optifast programs are the meal replacement shakes which are easy to use and simple to prepare and pack. They come in a variety of flavours such as banana, mocha, salty caramel, cookies, etc. which makes them a tasty alternative to regular meals.

In other words, Optislim and Optifast weight-loss products are a healthy, portable convenient choice for a diet on the go. Even more, they may prevent any temptation over fast food during high levels of hunger and also keep you satiable for several hours.

Though based on meal replacement shakes, Optislim and Optifast are weight loss programs that differ in many aspects. Buyers might notice an evident competition between these two brands when considering to implement them in their weight loss plan.

Each program has advantages and disadvantages, so it is advisable to inform yourself first before making a final choice and purchasing the products.

Here is a comparative overview of the Optislim and Optifast programs:

What is Optislim?

Optislim is a top-rated Australian wellness program that is designed for rapid loss of excess weight.

It is designed to support the process of weight loss and weight management by providing a Very Low-Calorie Diet (VLCD) and Low-Calorie Diet (LCD) meal replacements in a range of shakes, soups, and bars full of essential vitamins and minerals.

The Optislim VLCD Meal Replacement Shakes may provide the daily recommended intake of 25 vitamins and minerals when consumed three times a day. Each box contains 21 sachets with a flavour of either vanilla, banana, coffee, chocolate or strawberry.

Optislim is a cost-effective way that will provide you with a steady weight loss. All food replacements come in different flavours or in assorted packages.

Optislim’s most recognized products are VLCD Meal Replacement Shakes, Healthy Option meals, weight loss capsules, and detox products.

Each product is a nutritionally balanced but low in calories and fat.

What Is Optifast?

Optifast is a regimented program for rapid weight loss that includes shakes for weight loss that may replace 1 to 3 regular meals, according to an individual lifestyle plan.

The Optifast is a VLCD Program, meaning a very-low-calorie diet for severely overweight and obese people but also for people who want to speed up their weight loss through a ketogenic, i.e. low-carbohydrate diet.

The main highlights of the Optifast program are the Optifast VLCD Protein shakes in different flavours as well as the desserts, soups, and bars that provide satiety and maintain lean muscles while the body is in a state of ketosis-meaning it burns fat for energy instead of carbohydrates.

Despite the low-calorie diet, Optifast contains the essential amount of vitamins and minerals as well as protein, fatty acids, and carbohydrates that provide rapid loss of weight but balanced body functions.

The Optifast program is divided into four levels: Active Weight Loss Level, Intensive Level, and Maintainance level. Each stage has Optifast shakes, snacks, desserts, soups and bars that ought to provide the necessary daily intake of vitamins and minerals and trace elements.

The Active Weight Loss Level 1 is compromised of twelve to sixteen weeks of total meal replacement with the Optifast products. Fast-forward to the Transition Level of four to six weeks of slow returning to prepared meals and lastly, the Maintainance phase which balances the use of meal preparations and prepared meals.

The Optifast VLCD Intensive level included allows you to enter and proceed with mild ketosis by replacing up to 3 meals per day with the dietary products offered in the weight loss program.

The products also follow the Codex Alimentarius International Standards for VLCD/VLED.

Moreover, Optisfast is a medically supervised program with the support of health professionals who help their clients through monitoring, counselling, and classes, aiming toward a healthy lifestyle with positive eating habits and balanced weight.

Optislim vs Optifast

If you are in doubt about whether you should choose Optifast or Optislim for your diet based on a meal replacement plan, you should initially consider the cost-effectiveness of both of these programs as well their results in terms of weight loss and the possible long-term maintenance of the effects.

Both Optifast and Optislim are similar because they offer meal replacement products with essential nutritional value. However, Optislim limits its offer to meal replacements that promote weight loss whereas Optifast offers a medically supervised program.

Having in mind that calorie-restricted diets may harm a person’s health if taken without medical consultation and assessment, Optifast may be a preferable weight loss program due to the higher level of safety provided by the monitoring and assistance of health professionals included.

On the other hand, however, the Optislim Meal Replacement Shake is more cost-effective as the product contains 21 sachets vs 18 sachets of the Optifast Meal Replacement Shake per box.

In addition, when it comes to lifestyle and personal schedule, it can be said that Optifast may be quite a time consuming dietary solution for many since it involves monitoring, classes, reports, and counselling. If you opt for Optifast, be ready to incorporate another task in your busy routine.

If this sounds too demanding, then maybe you should consider Optislim as a more convenient dietary method. However, Optislim does not offer any support during weight loss nor step by step introduction toward weight maintenance and long-term healthy eating habits.

Although users of both Optislim and Optifast have confirmed losing weight through weight loss shakes and other dietary meal replacements included in the programs, Optifast holds an advantageous position in terms of maintenance of lost weight.

Optislim will induce weight loss through low-calorie meal replacements that provide quick results. The results may be fast achieved but hard to maintain in the long run since calorie-restricted diets are often draining and harmful to health.

The regimented program of Optifast, on the other hand, includes a maintenance phase as the last and longest phase of the program, where you would attend support sessions to consolidate your newly learned positive eating habits and thus, sustain your weight and figure.

Moreover, you can buy Optifast online at Chemist Warehouse or at clinics, hospitals and at certain doctor’s offices. You can order and purchase Optislim only in Australia through eBay or its official website.

Are They Good for Weight Loss?

Weight loss programs

Both Optislim and Optifast may make you lose weight rapidly. However, dieticians and health professionals are adamant to advise that diets with meal replacements are only a step toward your goal of losing and maintaining your ideal weight, but not a permanent solution.

The best long-term wellness results are obtained through a calorie-controlled diet and regular exercise.

If you want to lose weight through VLCD or diet loss shakes you must, above all, consult your doctor or health care provider before you decide upon taking up any fitness program or product.

Very low-calorie diets or weight loss programs based on diet shakes have a general lack of nutrition and practitioners often face exhausting hunger, fatigue and other side effects such as headaches, constipation, dry mouth, dizziness, and hair thinning.

In addition, scientific research by dieticians has shown that meal replacements, in general, cannot guarantee to provide all the necessary trace elements and nutrients that can be obtained through high-calorie meals.


Why Is Optifast More Expensive Than Optislim?

When considering Optifast vs Optisilm you may wonder why the dietary program of Optifast is a more expensive one.

The main distinguishing aspect of these programs is that although both of them offer a wide range of dietary products, Optifast is also a medically supervised program that offers three stages of dieting and weight management between 26 and 52 weeks, followed and monitored by health professionals.

Optislim is a weight loss program that is mainly focused on rapid loss shakes but it does not include medical assistance during the process of weight loss nor professional dietary counselling that may help you maintain balanced, healthy body weight and positive eating habits.

Are Optifast and Optislim Gluten Free?

All the OptiFast VLCD products contain a certain level of lactose and soy-based ingredients. Potential consumers with Coeliac Disease or gluten intolerance should have in mind that the OptiFast VLCD Chocolate, Cappuccino Flavour & Berry Crunch Flavour Bars are made of ingredients that contain processed oats. So, although these bars are not made with ingredients that contain gluten, they may still be unsuitable for the gluten- intolerant.

OptiFast shakes, desserts, and soups are similarly made of ingredients containing egg. Optifast Bars are also products that may contain pine nuts and peanuts.

Although Optislim is not a brand that offers a variety of gluten-free products, its OptiSlim VLCD Platinum Plus Meal Replacement Shake is a gluten-free friendly weight-loss shake, and one of the few suitable gluten-free options from this brand. Moreover, this is one of the rapid loss shakes that contain only natural colours and flavours and a mix of prebiotics and probiotics.

The Bottom Line

Losing excess body weight through diet shakes and dietary meal replacements may be a practical solution when you want to get rid of extra pounds and fat in a quick way.

Both Optifast and Optislim are convenient dietary programs that offer portable, nutritional meals that can provide a long-term diet regime on the go.

These programs offer effective weight loss plans in the shortest plausible time-frame of 2- 6 weeks. However, Optifast may be considered as a rather preferable choice for consumers due to its medically supervised plan and counselling during the process of losing weight.

Though Optislim is also an effective program, it is focused solely on meal replacements in the range of shakes, bars, and soups. For some people, Optislim may be a better option since it does not include diligent counselling, monitoring or classes.

Regardless of your personal choice when you opt for one of these dietary programs, you should always keep in mind that before starting off any of the VLCD diets, you should consult your doctor or health care professional in order to secure your safety and wellbeing.

Finally, VLCD and LCD programs and methods may help you to make the first step toward fighting obesity or excess body weight. When supported by assisting medical guidance, VLCD and LCD programs focused on meal supplements can be an effective and healthy way of losing weight.

However, the old golden rule of healthy, nutritional and balanced meals accompanied by regular exercise remains to be the best long-term solution to ideal body weight and figure.

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About the author

Claire is a fitness enthusiast with a flair for writing. She is dedicated to promoting a healthy, balanced lifestyle underpinned by long-term solutions. After being physically competitive, Claire put on significant weight during her university years. She made a decision to get fit again and is now helping thousands of individuals achieve their fitness goals. View All Posts

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31 thoughts on “Optislim vs Optifast: Discover Which Works Better”

  1. just to let you know – you can purchase Optislim at Chemist Warehouse and always have been able to, I did so today and have done so previously, and they DO also offer a gluten free soup.

    • Hi Amy, I’m not aware there are any issues but you should speak to your GP first as each individual situation is different.

    • Hi Claire thanks for your article, wanted to share that I have used Optifast with success. Once you get past the first 48 Hours cravings for food and salty/sugary snacks is minimal.
      I’m not much of an over-eater and often skip meals, but I am a complete sugar addict. Whatever the balance is in Optifast it just stops the urge to binge on sugar in its tracks. The shake flavours are pretty good especially the chai and feel like a treat rather than a meal replacement. I also like the cranberry cereal bar as a textural change. You also consume 2-4 cups of non starchy veg across the day. I’ve bought a couple of single serves of optislim to see if the $$$ savings are worth the change, but haven’t been swayed. (I haven’t tried anything from the optislim VLCD platinum though). I’ve also tried the meal replacement shake from Aldi, which were tasty, inexpensive but comparatively they are loaded with sugar.
      If you shop around you can usually pick up Optifast for under $3.50 a serve and under $3 if you’re really lucky. My income relatively low but I don’t find optifast unaffordable.

      Whatever works 🙂

    • Hi Michelle, you could try. Just note that you may not be able to tell which one is working/not working for you.

  2. I’m 72, and obese. I would like to try either OptiSlim or OptiFast to get a kick start to losing weight. Would you recommend for me?

    • Hi Maggie, I can’t recommend one because each individual situation is different. You should speak to your GP or someone who helps you look after your health to determine what the best option is for you personally.

  3. Hi. I’ve been drinking optifast shakes once a day as a meal replacement but eat healthy throughout the day. I’m not following their diet to the exact no am I under any supervision. So just for a meal replacement am I better off just doing Optislim

    • Hi Tess, if what you are doing currently is working for you, then there is probably no point in switching. If not, then you could consider trying Optislim.

  4. I am obese and I need to lose weight quickly. I am leaning towards optifast but I am on the disability benefit as well as I can’t work . Can I still do opti fast without the medical support . Also which is the program where you eat meal replacement shakes 3 times a day is that optislim or opti fast can you get this in nz .

  5. Thanks for this great article. I have done shakes before both with and without medical supervision and no matter which one you choose for your initial weight loss (I am aiming to lose 40kgs) it is definitely the next step that is the most important no matter which product you chose in my opinion.

    I am on day two of optislim and so far so good, water intake is very important and even though I HATE water with a passion I am forcing myself to do it.

    Good luck to everyone, it is hard but it is worth it.

  6. I’m currently doing the optislim program
    I have done this through my GP
    I’ve lost nearly 16kgs in 7 weeks.
    I’m also on Duromine so I have no cravings at all and i don’t feel hungry at all

  7. I was sceptical about weight loss “shakes”, as I have seen several people use them without success. However, I am sure that they were not exercising or cutting back on “treats” either.
    I am a 66 yr old Type 2 diabetic, and was advised to try Optifast Shakes by my dietician. I am not grossly overweight, but finding it difficult to shed the final 2-3 kgs to reach my optimum weight.
    I was surprised to find how good they tasted and how full I felt after consuming one.
    Admittedly I have only been taking one per day, and am only on day 8, but I feel that this will work for me. Thanks for the comparison article, I have a friend that is using Optislim and will be interested to see how that works for her.

  8. I’m currently using Optifast and have been since 1/1/2021 – to date I have lost 8kgs.
    My day consists of 3 Optifast products, a shake in the morning and I alternate between a shake or a bar at lunch time. Dinner I have 2 cups of non starch veggies and 1 Optifast dessert which I freeze for 20 minutes and have this as an ice cream.
    The only problem I’m facing, I only have supplies until the 11/2/2021 – all Optifast suppliers in New Zealand are out of stock Therefore I may have to consider the alternative by using Optislim. Hopefully it will have the same results.

  9. Ingrid I do the exact same regime with my optifast 😱! Like exactly to the letter! (But plus one thing: In the morning I add 2 spoons of coffee dissolved in the water I add to my chocolate shake & make it a mocha ☕️ teehee 💖)
    & then like you I mainly go with the bars at lunch which are great for a hit in texture – esp if I have choc or cappuccino. They are both amazing. I almost feel like “who needs sweet treats when lunch pretty much feels like I’ve eaten a few Mars Bars but instead of feeling guilty I am FULL & SATIATED from it – so you get lunch,nutrients,the afternoon pick-me-up junk food+all the satisfaction It’s the best!
    And I love veges so I’m happy to eat them any which way so dinner is a breeze for me 😊 then my lemon creme icecream at dessert time is just the best end to the day 🤤 😋

    – it’s hardly a diet at all!
    Haha, sometimes I feel guilty that sticking to this program is so easy 🤭- cause everyone else is finding it all so hard & im actually enjoying the food I feel like I’m cheating lol! (I’m not – I only take in 1000-1300/day.. I haven’t moved down any levels because I don’t want to haha ☺️ I like the food but I’ve already lost all the weight & my bmi is now 17.2 (*just*) underweight – but I’ll make up for that at easter next weekend for sure

    – but can I stay eating like this to just maintain my weight? I finally found foods I like, & the contain all the daily recommended vitamins & minerals for the day so I don’t know if it’s a problem or not?
    I’d love to know what you guys think or what you’d do in my situation 🤔 😔 (expert opinions are also welcome, I can take it)

  10. By the way – we also had ALOT of availability issues with certain Optifast products here in Australia for the past few months, but in the past week or so I’ve noticed one or two products have been coming into the shops & so they should soon all be back on for sale 👍🏻
    (I was originally told to expect my particular faves by April (chocolate bars have not been available since late last year here lol) – I was told by the people from the optifast website, & so from what I mentioned I’ve seen it looks like that is when it’ll all be back to normal 😊 so if nz still has empty shelves just give it 1-2weeks & you should be back in business! 😉 👌🏻
    Ingrid I hope you worked something out when you ran out in the middle of last month… I hope you didn’t stray from your diet & that you kept on track to real your goals 🤩😇

  11. I’m doing weight loss surgery and it was written on my sheet to use optifast but it is expensive so can I use optislim instead? I need to start these shakes 3 wks before surgery to help shrink the liver. So which one Is best?

  12. I lost many kilos on Optifast and a no-carb diet. I am healthy now, considering where I was as a morbidly obese woman. I can not tolerate Optislim. To me it tastes like cardboard and makes me gag. I spoke to a Bariatric Nutritionist and a BariatricbDietician about my dietary options. They are qualufied to give advice. I just mentioned what worked for me. I


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