Slim Fast has been around for ages and will work if you can get by the monotony of the shakes--we do think it's worthwhile as a two-week jump start to your diet before you move on to a more sustainable eating plan. We simply think most people will become bored of this diet after more than a few weeks, and we have concerns about long-term nutrition being fulfilled if you stay on it for months. Nonetheless, there are scientific studies which show that liquid replacement diets of this type can be more effective than calorie-controlled diets at losing weight, so if you can persevere, you should see results. Slim Fast is less hardcore than the Very Low Calorie restricted diets like Medifast.
Of course, like any liquid replacement diet, Slim Fast does nothing to teach a dieter how to eat long term, how to keep the weight off once they come off. If you simply return to poor eating habits, you will gain the weight back with a vengeance due to the "famine effect." So if you do try Slim Fast and have some success but haven't been able to maintain your weight off in the past, it's important that you transition to a more realistic long-term diet.
One complaint is that Slim Fast products give some dieters gas and upset stomachs. If you have a disorder like Irritable Bowel Syndrome, taking Slim Fast may well trigger that as well.
Menu: This is not a cheap diet to follow--the shakes and supplements are pricey for the small amount of calories they provide--another reason to keep your stint with it limited.
Many users find Slim Fast shakes neither satisfying nor tasty. While sweet and packing 217 calories (for the chocolate ready made shake) in a 325ml bottle, they seem watery and don't really fill you up. Some users call it "Death by Milkshake" as they can only last so long on milkshakes for most meals, often a week or so. If you use the bottled shakes (about twice as costly compared to powder, one tip from many dieters is to keep the tins in the fridge to improve flavor, and serving them with ice helps as well. For the powder shakes, you'll probably lose a few calories just trying to mix and get out the lumps, and a dishwasher may have trouble getting your cups clean, but this is definitely the cheaper option.
Their bars appear very sweet to many users, so you get a high and then crash until the next mealtime.
They are very chewy and can be a bit of a mouth workout--the chocolate bar also packs 215 calories for a 60g bar.
You're supposed to cook up a healthy dinner of around 600 calories, but Slim Fast even have some of their own frozen ready meals if you want to leave it all to them, and spend a bit more cash.
Prices: The prices vary dramatically, but some of the best deals are from Amazon (like a 31.18 ounce tin of chocolate shake mix for ~$25), and if you order online you can even get your supply delivered to your door for free (great to avoid other temptations in store).