slim-fastSlim Fast is a weight loss program that substitutes cooked meals with shakes and bars. The program is over 25 years old, and is currently a brand owned by Unilever.

Slim Fast has been a popular choice for weight loss with it’s huge range of weight loss shakes.

However in recent years, Unilever has struggled with declining sales – at first blaming the popularity of Atkins.

The original Slim-Fast shakes were criticized for being too high in sugar. This was rectified by replacing sugar with the artificial sweetener Splenda. The new range of Slim-Fast products are called Optima.

Slim Fast Products

The Slim Fast offerings comprise the following:

  • Optima – Shakes (Ready-to-Drink), Bars, Smoothies, and Powders
  • Original – Shakes (Ready-to-Drink), Bars, Smoothies, and Powders
  • High Protein – Shakes and Meal Bars

A typical shake (Optima Cappuccino Delight) contains the following:

  • 5g Fat
  • 24g Carbohydrate
  • 10g Protein
  • 180 Calories
  • 24 Vitamins and Minerals

Diet Plan

The diet involves replacing two main meals with Slim-Fast products. Each day will also include one “Sensible Meal”, and fruit/vegetable snacks.

A sensible meal is based around a lean protein (such as skinless chicken breast, or fish), carbohydrate (potato, rice, or whole wheat bread), and a large serving of vegetables.

Sample Meal Plan

Optima Cappuccino Shake &
1 slice frozen French toast with 1 Tbsp light syrup
1 cup grapes
Slim·Fast Optima French Vanilla Shake &
1/2 roast beef sandwich
(2 oz. Roast beef, 1 slice whole wheat bread, 1 tbsp horseradish, lettuce, tomato)
Afternoon Snack
1 apple
Chicken Veggies Grill:

  • 4 oz. Grilled chicken breast (no skin),
  • 1 small baked potato with 2 Tbsp fat-free sour cream,
  • 1 cup steamed broccoli with
    1 Tbsp Parmesan cheese

1 cup melon

One slice low fat pound cake OR Peanut Butter crunch Snack bar.

Find other healthy low Calorie recipes here.

Are Slim Fast Users Successful?

The Slim Fast diet is a sensible and workable plan, and many people find the convenience of using meal replacements outweighs other diet plans.

However, long-term, results using Slim Fast and other meal replacement diets isn’t common.

There is one study that Slim Fast cites claiming that “People who followed The Slim·Fast Plan routinely to lose and manage their weight were, on average, 33 pounds thinner after a decade as compared to a matched group from the same community who did not participate in the study. (reference: Blackburn GL. et al. Obesity Research 2003;11:A103)”


 By Mizpah Matus B.Hlth.Sc(Hons)
  • Noakes, M., Foster, P. R., Keogh, J. B., & Clifton, P. M. (2004). Meal replacements are as effective as structured weight-loss diets for treating obesity in adults with features of metabolic syndrome. The Journal of nutrition, 134(8), 1894-1899. link
  • Eckel, R. H. (2008). Nonsurgical management of obesity in adults. New England Journal of Medicine, 358(18), 1941-1950. link
  • Anderson, J. W. (2004). Combination approaches to weight management. Pharmacotherapy, 4, 16. link

62 Comments or Reviews

Comments now closed
  1. Maria

    Can I switch roast beef with ham or turkey deli?
    R there other options for dinner besides chicken?

  2. Gail

    Has anyone tried the zigzaging suggested on the diet calculator and does it work?

  3. Andrea

    Where do you find a list of regular foods you can eat together with the shakes and bars

  4. pani

    there used to be these slimfast bars, the traditional ones, they were the best. these are called optima now. the snak ones were great. they discontinued. i always lost weight with them and now i cant get them from anywhere. they were square sized ones with red label, says slimfast lunch and breakfast meal option ontop. lower in calorie. and i think those were the first slimfast snacks made. aaahhhhh wish i could find them. i dont like these new snacks. they have too much carb and calorie , which i dont find helpful. its just too much. !!!!!!!!

  5. Brenda

    Hi everyone. I started slim fast April 29, and so far have lost 17 pounds. And I do go out to eat at least once a week, you can’t deprive yourself. And I also only weigh myself once a month, I think it’s better that way, after that time of the month, I just feel it makes a big difference.

  6. PB

    I started the Slim Fast diet about a week ago. I work out every day at the gym for about an hour and a half to two hours, and every few days do about 45 minutes of Zumba. I’ve been doing relatively well. The one thing I’m worried about is after I reach my goal weight. I’m worried that once I stop drinking slim fast, I will gain my weight back. Once I’m at my goal weight, I will obviously make sure all of the food I eat is very healthy and sensible choices. No more junk/fast food. Will this work? I’m just so tired of feeling like a pariah because I’m overweight.
    So, if I generally eat a low calorie diet and continue exercising on a regular basis, will I be able to maintain my ideal weight?
    Thanks a lot

    • ted

      Hi PB, You’ve discovered the problem with meal replacement products. They never teach you to eat right. Why not save your money and just eat healthy calorie controlled meals now? Here’s a site that can help with eating plans and calorie calculators. Good luck! 🙂

  7. DRiley

    Just finished my first week on SlimFast 321 plan. Messed up a few days with an extra piece of chocholate or granola bar here or there but still lost 2 lbs. Haven’t increased my exercise but still managed to lose. On to week 2 this time I’ll be better. Goal 140 current 161

  8. Sarah

    Hi there, I started Slim Fast 4 days ago-I broke last night and had sweets etc but I’m back on it again today. I want to lose 16 lbs, I would like to hear from anyone else who has slipped up and got back on it.

  9. lynn

    I started this diet three ago and lost 10lbs. For coffee lovers the mocha, vanilla, and choc. taste great in your coffee and you dont have to add the extra calorie with creams or milk and sweetners.

  10. gusta

    i have been looking for slim fast coupons and without luck, i can’t find any.. Will someone help me find them please

    thank you

  11. sadie

    for those who live in the uk, there is a really good deal on slim fast products in tesco at the moment. i’m stocked up and its day one for me so wish me luck!!

  12. stacy12

    im starting the slim fast diet today! i weigh 170 lbs… im hoping to lose 60 pounds in 2-4 months… it is suprisingly filling! hope it works for all you guys!

  13. Michelle

    I am 3 days into my 4th week on slim-fast…although i am lossing its pretty slow compared to what others say they have lost. I have a shake for breakfast, a snack bar mid morning, a shake for lunch and another snack bar in the afternoon. I have a healthy dinner. Sometimes i have the recommended 3rd snack if I need it later. So far i have lost 7lbs I am not a very big person but put some pounds on when I gave up smoking over 4mths ago that I want to come off.

  14. beth

    can the slimfast 321 plan work if you go out to eat?

    • ted

      Yes, With Slimfast you are to eat one healthy meal a day so Your eating out could be that meal, but you have to choose something healthy from the restaurant .

  15. milissa

    i started slim-fast 2 weeks ago and i am almost to the 10 lbs mark i love this diet it is really easy to follow but i changed mine a little bit to fit my schedule i have a shake for breakfast a shake for dinner a snack bar or another 100 calorie snack and i eat what ever i want for dinner since i already have a slow metabolism i did not get hungry before this diet i just ate because i knew i had to in order to live and i still do not get hungry but i also do not get super full or bloated anymore

  16. Amanda

    I just started the diet today! Had a shake this morning, snack bar, and a shake for lunch and I feel full. It’s amazing! Loving it so far

  17. LaDonna

    How can I get cappiccino flavored powder mix in Slim Fast. All you have is choc, strawberry and vanilla..I won’t buy the cans since the recall….

  18. Jamie

    I used slim fast to lose weight when I had my first daughter and it worked great…well another kid and about 5 years and I am the biggest I have been about 190lbs…I was diagnosed with PCOS and from the way the Dr. described it one day I will become a Diabetic unless I lose weight, I am also trying to concieve so before it will work I need to lose some weight. I hope this works with the help of some medicine she has me on.

  19. Sharon

    Hi, am willing to try for this slim-fast diet. Is there any store here in UAE who are selling this product?

  20. Ilse

    Hi I would like to know how I can buy slim fast in South Africa, do you have any distributors here, I really like the product, we stayed in Ireland for a year, and I started the Slim Fast there, I lost so much weight, just love your product.

    Kind Regards

  21. Ella

    Can I take slim fast if I have a cholestorol problem?

  22. Cheri

    i lost 20 pounds in 2 weeks doing slimfast. all i do is drink 2 shakes a day have one healthy meal and 3 snacks in between. i love it.

  23. cheska

    is slim fast really works?

    • ted

      @cheska, anything that causes you to eat less Calories works, but the question is does slimfast teach you to eat smaller more nutritious meals or is it just a quick fix that will not generate long term results?

  24. margaret

    i just started doing slimfast i weigh 185,and i want to loose 50 pds. i eat 3 snacks 2 shakes 1 meal usually a salad. i use to weigh 253 i got to 165 doin atkins. i gained
    some back i love sweets so hopefully it works i love the penut butter crunch snacks. so i walk 30 mins daily.does anyone know if you can have coffee black or just water

  25. Ofelia

    My mom did this diet for 8 months and lost 70 pounds. She kept the weight off until she had another baby. I reccomend to anyone who plans on being active. If you just think you can lose the weight and not gain it back and your one of the lazy ones, this diet is not for you. Yes this will make you lose a good amount of weight but exercise is the key to keeping the weight off afterwards.

  26. tori nala

    i didnt know it had suger in it ill try it. Thank U

  27. Kim Nguyen

    I just went out today and got the SlimFast powder shakes, can shakes, and the snack bars, I’m planning to lose some weight after gaining ot back from previous diet pills (Fast Slim) I weigh about 137.. hopeing to go down to 120.. i’m a bit on the wider side since I’m only 5″2…

  28. barb



  29. margaret

    Hi im considering doing slim fast! Iv done ww and unislim and lost weight but this time none of em work for me! Need something new and this be it! would 2 shakes a day-slim fast and my own made dinner, and bowl special k last snack with a slim fast treat lose me weight! How much that way i expect lose a wk! Im 12st 7lb now 5ft 3in wanna reach 9st 7lb! eventually 9st.

  30. Linsey

    Hey guys…I am currently doing the Slim Fast plan. I have pictures posted from when I started (Jan 1, 2009) and just posted recent pictures. I will keep posting pictures every two weeks until I get to my ideal weight. If you want to track my weight loss with me and see if Slim Fast really does work…come check out my site! 🙂

  31. LORI

    Good Luck Catherine! I’m thinking about the slimfast program…I haven’t tried the powder shake mix. Which is the best flavor? The bars are great though. And does anyone know of a coupon website for coupons for slimfast products?

  32. gina

    i jus started slim fast yetersday, & i do think this is going to be somethng i can follow, do you guys snakc after a shake like a fruit or do yas just drink the shakes n do the dinner?



  34. Am

    I used slimfast but apparently didn’t get enough fiber or whatever because it made going to the bathroom very difficult and painful. Never stayed on the plan because I couldn’t stand the bathroom issues.

  35. Amanda L.

    I weigh approx. 135 lbs, and am only 5’2″. The only area it shows is my stomach, the rest of my body is thin. Therefore i would like to drop to around 125. I do not have the time to prepare food and cook (breakfast and lunch) to successfully follow the other diets on this site. Therefore i checked into SlimFast for the convenience of the meals. For those of you that have tried this diet, and were successful, how much time did you spend on exercise? Other than walking, do you recommend any other exercises that were successful to you??

  36. Joseph

    I am excited about slim fast diet, not sure how much it is going to be effective for me. From I understand this to work. Lets see…

  37. Anonymous

    I’m gonna go try slimfast 4 a while.& c how it goes! I had a shake b4 when I was little didn’t taste 2 good but I need 2 loose atleast 10 or 15 lbs!! I weigh 140

  38. Shannon

    I used Slim Fast in 2003, substituting shakes for breakfast & lunch Mon – Fri. I lost 50lbs in 6 mos. Also lowered my cholesterol. But once I stopped using the plan, I gained the weight back….EVERY POUND.

  39. random

    is slim fast actually good to loss weigh???, because every time i see the percent of fat and carbohydrate is very high..

  40. Sheila

    I had gastric bypass a year ago and have to have a high protein diet. I can’t handle the protein shakes, but love the slim fast peanut caramal high protein bars. Now my wal-mart store says that bar has been discontinued. Is that on wal-mart’s end or on yours. I can’t stand chocolate and that’s the only other choice you give chocolate haters. What’s the deal? Who’s going to help us picky folks out? Why is it that you have to eat chocolate or you don’t get any other choice? Come on, give us some other flavors!

  41. Jackie S

    Someone who weighs 120 doesnt need to lose any weight.

  42. Krystle

    I love this diet I’ve lost about 5 lbs. in two weeks. I had got off it, but now I’m back on again and I love it!!!!!

  43. Courtney

    I am small framed but tall. I weight 135 lbs and 5’8″. I definately look the best at 126-128. So I am trying to lose 9lbs. I am counting calories and eating fruit for breakfast, a sensible lunch and doing a shake for dinner…I am a HUGE comfort food eater…so trying to eliminate that bad late night eating..will let you know in 2 weeks how its going!!

  44. Joan

    I weigh 120 pounds but am short and need to lose 5-8 pounds. What plan do i follow?

  45. Melissa

    I’ve been on the Slim Fast program since November 2007. I have lost 30 lbs. I have hit plateaus, which lasted approx. 1 to 2 weeks. Never gained during those periods. It seems that if I just continued being consistent with the plan, it would just kick back in and I would lose another 5-8 lbs. before I hit my next plateau. When you hit one, DON’T give up. One little trick I noticed was when I hit one of those plateaus, I consistently eat 2 servings of Low Fat Cottage cheese with my lunch shake ea. day., rather than a sandwich. This still provides less than 200 cals., and also provides approx. 28 grams of protein to go along with the 10 grams of protein in your shake. Sometimes I throw a couple of slices of strawberries, or some blueberries, etc. (a little applesauce with cinnamon is good, as well. I do this for a week straight and it seems as though that is all I have to do to get through my plateau. Just take away some of your carbs. for a little while. GOOD LUCK EVERYONE AND DON’T GIVE UP. SLIMFAST IS A HEALTHY WAY TO WEIGHT LOSS!!

  46. Rhonda

    I agree with anonymous, this is just another excuse people have used for not losing weight! When you’re sick and tired of being sick…. and tired….. all the time you won’t let a website being down hold you back from reaching your weight goal. I’ve been in their shoes before using any and every excuse I could find to come up with an excuse as to why I couldn’t lose weight. Before having my daughter I had lost 45lbs. walking and watching what I ate, after having a miscarriage and feeling sorry for myself I began to slack up on my walking and started eating all the wrong things. I got up to around 150lbs and then found out I was expecting. After two years of making excuses I’m finally ready to lose the weight and trust me nothing will hold me back from reaching my goal!

  47. Anonymous

    I have an issue with the people blaming the website being down as the reason why they will no longer use slim-fast. Are you serious? Even though you are losing weight, the website is your reason? That’s just another excuse to not go through with your weight loss goals. A journal made from paper that you can buy at any store will do just as good a job, if not better, of keeping track of your weight, calories, food intake…all of it. It may be a little more work on your part but so what? It’s still you taking control of your eating habits. But if you MUST have a website to track what you eat, there are all kinds of generic sites where you can track any type of food, log your weight and your exercise and all that. Since looking those up might be an issue as well, here’s one…

  48. me

    wow i’m proud of u good job!!!

  49. itworked

    ive been on this deit for about 18 months ive lost 170 pounds

  50. Nancy R

    What impact does Slim Fast have on Cholestrol?

  51. Crystal C.

    It’s completely ridiculous that the site is down, especially for how long it has been down. I really want to sign up and I can’t. I think i sat here for 45 minutes trying to figuire out why it wouldn’t let me register until i came here and realized their site is down. They need to state on their home page that their site is down.. not after you look through everything!

  52. Janice

    I, too, really wanted to use the slim fast website, which has been down for “maintenance” for over 30 days now. I found an alternative! I’m using their Canadian site! Good Luck!!

  53. Joan M.

    Why is the website down for so long – it is ridiculous – not even an explanation of what is going on. I doubt I will ever use Slimfast again.

  54. Sandy

    I’ve been trying to begin my weightloss plan with slimfast many days now, but due to the website being down I havent been very successful. This is VERY unprofessional to have their website down this long. Im so frustrated that Im moving on to something else to guide me in my weightloss. There is no excuse to have a website down this long!

  55. disgruntled Slimfaster

    The slimfast website promised to be there to help me lose weight. I used their journal, and logged my weigh-ins on their site. Then they closed their site for mainentance almost 6 weeks ago and haven’t brought it back up yet. No explanation. Just that it’s undergoing maintenance. 6 weeks of maintenance? Get real. I’m so angry with them that even though the program was working for me I won’t use them again… The website was a wonderful rug that was pulled out from under my feet. I think they are jerks and hoping anyone with any success gains all their weight back during this time.
    Anyway, their products have too much fat and sugar and not enough nutrition. It’s cruel to promise to be there and say hey use our website as the foundation of your weight lose program and then take it away without even so much as an apology or the delay.

  56. Tisha

    I have beeb doing slimfast for awhile and fell in love BUT I moving away from it considering the fact that slim-fast contains saturated fat, too much sugar, hydrogenated oils, and it is artificialy flavored. These are all the main things to stay away from.

  57. Betty

    I have tried the Slimfast plan and lost 30 lbs and have kept it off for almost 2 years. I still follow the plan to a degree to maintain the weight loss.

  58. Marilyn

    I would like for everyone to know, who are thinking about losing weight and have tried everything under the sun with no results, to look at the slim-fast plan. Slim-fast was the only diet plan that I have tried that have given me such dramatic results. I am a large framed woman with large bones. I am 5ft 8inches tall and I weighed 253 pounds. I have been on the slim-fast plan for six weeks and have lost 17 pounds. I have never dropped weight so fast in my entire life. I take a shake for breakfast, another for lunch, and eat a nice supper. I feel so much better. Try it everyone, and you will like it.

  59. Adrian

    After doubling my weight over the last 10 years, I struggled to get and keep my weight off. So far, I’ve been on the Slim Fast diet for one week, and I have lost almost 6 pounds! Thank you Slim Fast!!!!