Slim-Fast vs. Medifast

Post image for Slim-Fast vs. Medifast

During a recent visit to Target, I was checking out the meal replacement bars and noticed that Slim-Fast has completely revamped its product line and redesigned all their packages to tout a Slim-Fast 3-2-1 plan. It’s got a ring to it, but it also sounds suspiciously like the Medifast 5-1 plan. My girlfriend was picking up some of these to eat on a road trip because I wasn’t going to share my Medifast bars with her. But as a Medifast fan, I was intrigued and a little irritated by the Slim-Fast 3-2-1 concept. I decided I would investigate it a little further as soon as I could spare the time.

The last few months have been the very hectic wrap-up of a completely crazy year. Since mid-October, I’ve driven to Los Angeles to drop off the girl, flew back to Oklahoma to pack my things and drove to Austin to start a new job. I stayed with friends in November and finally moved into my own place earlier this week. After 6 months of unemployment, things finally seem to be coming together and it’s pretty exciting. However, I’ve definitely not been 100% on Medifast. To be honest, I really haven’t been on it at all. I have been replacing a few meals each day with Medifast bars or shakes, but I’ve also had a lot of celebratory dinners, a big Thanksgiving and way too many Lone Stars. I’m still feeling great and haven’t gained too much weight, but I’m definitely not losing weight either. I completely blew my goal. But I haven’t given up.

For the first few weeks at my new job, I ate the Medifast Crunch Bars during the day. I love the bars and it was super-convenient. I just kept them in my desk drawer and ate them on a regular schedule – along with a lot of water. It also kept me from wasting money on lunches at restaurants. But I ran out of the bars and haven’t been able to reorder yet for financial reasons. So with a tight budget and a determination to stay on some regular eating plan, I started thinking about Slim-Fast again. This time the Slim-Fast 3-2-1 plan seemed a little more appealing. I decided to try them out.

I headed to Wal-Mart because I figured they might be a little cheaper than Target. To kick things off I bought three types of bars:

  • Chocolate Nougat Gone Nuts Snack Bars(6 bars) $3.88
  • Nutty Chocolate Chew Snack Bars (6 bars) $3.88
  • Chewy Chocolate Crunch Meal Bars (5 bars) – A little over five bucks.

As you can see, it looks fairly inexpensive at first glance. If you decide to try out the Slim-Fast bars, you’ll notice that from looking at the box, it’s hard to spot how many bars you actually get. It’s definitely not clearly labeled. So check the nutritional information to see the number of servings per box.

The concept behind the Slimfast 3-2-1 plan is that you eat 3 snack bars, 2 meal bars or shakes and 1 healthy meal that you prepare yourself. It sounds strangely similar to Medifast. You can check out the Slim-Fast website for details. You’ll find a glossy site with lots of nice photos but not a ton of technical information as far as fat, proteins, sugars and carbs go. The main thrust of the Slim-Fast 3-2-1 is really on helping you reduce calories. Based on the nutritional information I could find, there is no mention of getting your body into ketosis – which is the calorie burning state that makes Medifast seem so miraculous.

The first time I tried the Slim-Fast bars, I thought they pretty delicious. They’re much more reminiscent of traditional candy bars than the Medifast bars. On my second batch, I bought some Sweet and Salty Chocolate Almond meal bars which I really liked. Unfortunately, the nutritional content of the bars is not on par with Medifast. For one, Slim-Fast uses high-fructose corn syrup which I had successfully eliminated from my diet until this experiment.

Making matters worse: I was almost immediately hungry after eating one of the Slim-Fast bars. When you get in a groove with Medifast, your hunger cravings really go away after a day or two. While eating the Slim-Fast bars, my hunger cravings actually went up. I could almost feel my blood sugar spike and drop after eating one.

I am not a food scientist or nutritionist, but the key differences between Slim-Fast and Medifast seem to break down as follows:

COST: I’ve tried breaking down how much the Slim-Fast 3-2-1 plan would cost once all the factors were figured in. Unless you ate something extravagant for your 1 meal, Slim-Fast would definitely be cheaper than Medifast. For more information on this, check out my article about the cost of Medifast. You can also buy Slim-Fast just about anywhere, so it’s a little more convenient.

NUTRITION: Medifast seems to be the clear winner here. Not only is it approved by over 20,000 physicians, the majority of Medifast products are lower in sugar and carbs. Medifast products are heavily soy based and they do not use high fructose corn syrup.

VARIETY: Medifast completely dominates in this area. On Slim-Fast 3-2-1, you are limited to bars and shakes. On Medifast, you’ve got shakes, bars, puffs, soups, oatmeal, pudding, pretzel sticks and a bunch of things I’m no doubt forgetting.

Based on my limited 3-week experiment, I’ve started to think of Slim-Fast 3-2-1 as a junk-food version of Medifast. If you’ve got 10 pounds or less to lose, this might work for you. But I have trouble imagining anyone with a significant amount of weight to lose having success on this plan. I really wish that Slim-Fast 3-2-1 was awesome, because the main thing I don’t like about Medifast is having to mail-order it. It would be great to be able to buy Medifast at Wal-Mart or Target. But in all other areas, Medifast totally crushes Slim-Fast.

If you’re serious about losing a significant amount of weight, look no further than Medifast.

During my Slim-Fast 3-2-1 experiment, I only tried the meal and snack bars, not the shakes. But in hindsight, I’m glad I stayed away from them because there has been a recall.  From the Slim-Fast website:  “Englewood Cliffs, NJ, December 3, 2009 – Unilever United States, Inc., in cooperation with the U.S. Food and Drug Administration (FDA), is conducting a nationwide voluntary recall of all Slim-Fast® ready-to-drink (RTD) products in cans, due to the possibility of contamination with Bacillus cereus, a micro-organism, which may cause diarrhea and possibly nausea and/or vomiting. The probability of serious adverse health consequences is remote. The products were sold in stores nationwide.” Not cool!

{ 27 comments… read them below or add one }

Sandy Kachel December 4, 2009 at 4:35 pm

That was one of the best blogs i’ve read in a long time. I too have drifted away from the MF plan although I eat a few meals a day. I’ve lost 41 lbs with 40 more to go. While MF is quite expensive and a pain to order, it’s easy to see what other options are out there. Thank you for letting me know that slim fast is NOT a good idea. Keep up the good work and I’m pulling for you.



Christopher December 6, 2009 at 12:13 am

Thanks for the kind comment! And you’re halfway there. I think when you have a significant amount to lose, there are going to be times when you drift off the program. The key is to stay eating as healthy as possible and remember the things you have learned from being on the program. I am going to be going at it hardcore in January and will be documenting my progress here.


Jim Allen December 5, 2009 at 9:01 am


Great article ! Well done.

Jim Allen


megsadevil January 9, 2010 at 1:38 am


I was doing slimfast shakes (with half a banana and some peanut butter) before workouts and for breakfast for a few months and having bars during the day. You're right: it's cheaper and more convenient, but it's higher in calories and sugars, and lower in protein thank Medifast.

Looking forward to going though this journey with you through the virtual world! My parents have been on it for a year and have lost a combine 150 lbs! My younger sister joined right before Christmas and me just before Thanksgiving. We are the only family of four at our center, and I plan on submitting us for the 2011 People Magazine's Half Their Size issue (Maybe 2012, but I'm doing it!)

Good luck to you and keep up the good work!

Oh – and I hear ya about your girl-friend stealing your bars. The good things is that my boy-friend is on board and we do Lean and Green together (he gets carbs because he power lights) but the man is always eating my Peanut Butter Crunch bars! HELLO!!! These are my Reese's Peanut Butter Cup replacements! Oh and the crackers…he really likes the crackers!

Have a Meggerific Day!


getskinnybehappy January 11, 2010 at 4:23 pm

Hey Meg – Thanks for stopping by and thanks for your comment. Very cool about your family all doing Medifast. I will look forward to seeing you guys in People! You better hide those Peanut Butter Crunch Bars. It really sucks when you run out. I think they're one of the best things on Medifast.

To clarify, do you guys go to one of the Medifast centers? I'm curious about how they work. Can I just go to one and buy the food instead of doing mail order?


Joanne January 23, 2010 at 6:56 pm

you can buy from the center one time but you pay a higher price…I joined before i tried the online…Online is cheaper expecially since they offer $50 off and the VIP progrom was ok too to save some money…I also went off of it but am starting back this week.


eddiejenkins January 25, 2010 at 1:34 am

Great article! It appears Medifast is a clear winner! Thanks for sharing!


Dena October 8, 2010 at 9:45 am

Thank you for the article!!!! I was just contemlating slim fast because of the convienence and price but I was affraid they didn’t compare in weight loss like Medifast. I love how quickly I lose weight with Medifast. It is really amazing. Since the point of eating this food is to lose weight I think I am going to stick with Medifast. I am curious though, did you lose any weight with Slimfast?


Christopher October 26, 2010 at 12:12 pm

I actually gained a little weight on Slimfast. I was hungry all the time. The Slimfast bars do taste pretty good, but they’re really sweet and really made me want to eat more in general. It is really convenient to be able to go to Target and buy them though.


Patti February 28, 2011 at 8:05 pm

I started medifast at the end of November 2010. I am pleased with my progress. Its the last day of Feb2011 and I have lost fifty pounds and 2 pant sizes and about to lose one more. My husband and I are doing it through my doctor which make it way cheaper not its still expensive. I have 66lbs still to go. I have been so inspired that I am going to be a rep for it. And I am also going to school soon to become a nutritionist and fitness expert. I promise myself I will never be hear again. This dirt not only is succeSsful but it its informative in ways. When I go shopping with my sister I look at all the labels now lol don’t do it on purpose I just want to knw what my family and I are putting into are bodies. All I know is I will be making most my food from scratch. MEDIFAST ALL THE WAY!


Kandi May 9, 2011 at 3:12 pm

Great article! Thanks! I’m pretty psyched about medifast now.


Barbara May 5, 2012 at 12:25 pm

Loved this article! I was actually going to the store to compare the different bars. Since I had eaten all of my MF bars and needed a replacement! I’ve only been on the program for 3 weeks and I’m about 2lbs away from losing 20 lbs total. I’ve been weighing everything and eating at the right times and have definitely increased my water intake. Love MF and love your site.


Jane May 26, 2012 at 10:22 pm

Try the south beach bars, I think they are 130-140 calories a piece (not the meal on the go bars) I take the entire box, unwrap the bars and cut off about a 1/4 of the bar and that seems to equal the medifast bar and they are somewhat comparable in nutrition…3 of the cut off pieces make another 100 cal serving (if that makes sense) I wrap in plastic wrap and vacuum them all in a foodsaver bag, and take out 1 and reseal, I actually bought 4 boxes and did them all at once, The south beach bar seems to be the only one even close to comparing as a substitute….(south beach refomulated their bars taking out the sugar alcohols that they used to have )..The peanut butter bars are my favorite…..


Paulina May 30, 2012 at 4:08 am

I’m with you, Medifast is great but a pain to have to order thru the mail. Wouldn’t it be drive to a store and buy just the amount you can afford on a given day.


Beth June 6, 2012 at 9:47 am

I found also that Medifast has better nutritional values. It is expensive, but adding up what I would pay for food at the grocery, it evens out…even a little less expensive. The only thing that bothers me is that they have seemed to change their formula for the food and it tastes different. Anyway, good luck to all!


me June 25, 2012 at 5:16 pm

medifast has chromium in all of their foods which is a appetite suppresant.. that’s why it works…
that’s why you arent hungry all the time…..


GetSkinnyBeHappy June 26, 2012 at 1:25 pm

Interesting. Not sure it’s in all their foods but it’s also important to note that a number of foods naturally contain Chromium as well such as bananas, grapes, garlic, etc. Also a small amount of Chromium is necessary for general good health.


DrewH January 23, 2013 at 9:11 am

Loved reading this post. Lost 50 pds on MediFast. Since being off of it I am inching back up. I had only bought the Medifast shakes (8 oz. 100 cal/each) when doing the 5 and 1 program of Medifast. Considered going on Medifast again but did not want the expense ($225/mth). Recently decided to buy 3 cases of Slim-Fast shakes ($80/mth) that will last me one month. Each bottle is 10 oz. and 180 cal. I pour in a shaker and dilute to create 4/ 6 oz servings (approx 400 cal/day). In addition I have also been eating a couple of 100 cal snacks and one lean and green meal per/day. The concept is as close to Medifast as I can get. My experience with Medifast was great. I was amazed that I could really lose and felt great. It was not “easy”, but was very exciting and encouraging to drop the pounds. So, we will see if this modification experiment will work with Slimfast.


Lynne February 6, 2013 at 3:58 pm

How did you pay only $225/mo.? Mine is more.


DrewH February 26, 2013 at 8:01 am

My first two months through a medifast support person was $225. But after that the discount or what ever I was getting it was more like $275. I think.


DrewH February 26, 2013 at 8:22 am

Well, it has been a month since I posted my Slim Fast idea. I have not lost a single pound. I am not doing the exercise that I found success with on medifast. But I don’t feel any less hunger cravings by using the slim fast shakes. I am considering doing medifast again this spring to trim back 20 pounds.


judy February 3, 2013 at 3:18 pm

I have been on Medi-Fast for one month, have lost 11 lbs. I haven’t gone into Ketosis and have been following the plan to the fine details. I have a counselor at the center and she said some people don’t go into ketoses for a long time. Has this happened to anyone else and do you have some suggestions as to what to do? I don’t feel hungry and am satisfied with my weight loss. Just wondering.


DrewH February 26, 2013 at 8:18 am

I searched to understand ketosis better. One person used three indicators: appetite suppression and reduction in carb cravings. Energy level rises and you feel mentally clear with no brain fog. A slight bladder irritation by the keyones with more frequent urination (also a certain scent change in the urine, not bad but different). Otherwise there are strips available somewhere that will tell you for sure.


Faith February 20, 2013 at 8:52 pm

I just started MF 5days ago. So far I good. How do you know when you are in ketosis?


DrewH February 26, 2013 at 8:19 am

I searched to understand ketosis better. One person used three indicators: appetite suppression and reduction in carb cravings. Energy level rises and you feel mentally clear with no brain fog. A slight bladder irritation by the keyones with more frequent urination (also a certain scent change in the urine, not bad but different). Otherwise there are strips available somewhere that will tell you for sure.


Deb March 16, 2013 at 5:16 pm

Does mf cause bad breath?


Angela June 1, 2013 at 12:37 pm

Ketosis actually can cause a bit of bad breath. I noticed it a bit after I started, but I’m losing enough weight that I don’t care very much. Lol. In addition, I drink a ton of water, and there is always mint tea or carrying a breath spray!

Some info on ketosis that I found pretty easy to read and understandable.


Leave a Comment

Previous post:

Next post: