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Slimfast Review: is it a weight loss and diet plan that works?




Slimfast is a well known meal replacement which comprises of a range of shakes and snacks to make weight loss simple.

Their line of low calorie products are designed for use as meal replacements and hunger busting snacks, packed full of protein, vitamins and minerals.

This Slimfast review will find out whether Slimfast is a good choice for those looking for a simple way to lose weight.


What is Slimfast?

Slimfast is a low calorie diet plan that focuses on regular small meals and meal replacements to achieve weight loss.

How to take Slimfast?

The Slimfast plan requires you to eat 6 times a day. Three meals and three snacks. Two meals are to be replaced by a Slimfast meal replacement, the third meal should be a sensible low calorie meal. In between meals you are allowed to have a 100 calorie snack. If men are using Slimfast they must increase the meal replacement and snack intake by 200 calories. You are advised to take 30 minutes exercise daily.

Who should use Slimfast?

Slimfast should be used by individuals who find it difficult to follow a diet plan and want a simple, easy to follow regime that doesn’t leave them hungry.

How much does Slimfast cost?

The cost of doing Slimfast depends upon whether you wish to use all the products in the range or substitute your own 100 calorie snacks. A 7 day starter kit costs around $30, so in theory, you can expect to pay around $120 a month for the full Slimfast plan.

Is Slimfast legal?

Yes, Slimfast is legal.

Is Slimfast safe?

Yes, Slimfast is safe to use.

Where to buy Slimfast?

Slimfast can be purchased from Amazon, pharmacies and supermarkets.

Does Slimfast really work?

Low calorie diets are proven to work as long as they are followed correctly by healthy individuals. There is no reason why you shouldn’t lose weight with Slimfast if you stick to the plan. However, some people do struggle to maintain the whole meal replacement scenario.

Are there any Slimfast alternatives?

Medifast. You can find our #1 recommendation here.


Slimfast is an easy to follow weight loss plan which focuses on helping users stick to a low calorie diet using tasty shakes, bars, cookies and more.

The Slimfast plan has been around for many years and is very well known. There are a huge variety of products now available, but the premise behind their formula and ease of use is still the same.

The Slimfast plan is beneficial to weight loss in the following ways:

Metabolism Support & Calorie Control

Calorie control when dieting is of course important, but the level of effect from this depends upon the efficiency of your metabolic rate.

The metabolism dictates the amount of calories  we use to survive and therefore, how easy it is to get into a negative calorie balance; forcing your body to burn fat for energy like thermogenics. (1)

The Slimfast plan guides its followers to eat six times a day, having three low calorie meals and three snacks – keeping your calorie intake low while leaving little time for you to feel hungry.

Eating regular small meals keeps the metabolism ‘stoked up’ meaning you burn more calories than you would if you were to go long periods without eating. (2)

Satiety and Hunger Support

All Slimfast products are high protein meal replacements or low calorie snacks which are designed to help you feel full for a number of hours, as well as satisfy diet cravings guilt free.

Replacing meals with a shake may seem like it wouldn’t be satisfying enough to keep you free from hunger, but protein is one of the best nutrients for prolonging satiety.

Studies have shown that a high protein diet not only promotes weight loss, but can also keep you feeling fuller for longer. (3, 4)

By reducing hunger, this helps you to stick to the plan and lose more weight overall.

Furthermore, eating a diet high in protein prevents the loss of lean muscle during times of calorie restriction. This is very important as lean muscle mass contributes to overall metabolic rate. (5, 6)

Nutrition Support

The theory behind meal replacement is self explanatory, you swap one or two regular food based meals for a shake or beverage. This helps you control exactly how many calories you are consuming at each “meal”.

When you start cutting out the food groups it also means you are restricting nutrition. Also, as you will be consuming fewer calories on the Slimfast Plan, it is even more important to make sure you are getting what your body needs.

Studies have shown that low calorie diets can result in some level of nutrient deficiencies. (7)

Slimfast is packed with all the recommended nutrients to reduce this risk and make sure you are getting the most from your replacement meals.


Slimfast contains a blend of ingredients that support both weight loss and overall health:

Dairy Protein

Slimfast products contain dairy protein which derives from fat free milk, or milk protein concentrate mixed with water.

Protein consumption is extremely important for the production and maintenance of lean muscle mass. Muscle is also a crucial factor in preventing overall metabolic rate from decreasing. (8, 9)

Eating adequate protein is also linked to a reduction in body fat and has positive effects upon high blood pressure. (10, 11)

Furthermore, protein is the key ingredient in Slimfast products which produces the feeling of satiety, helping you feel full until your next Slimfast snack or meal. (12)


The majority of Slimfast products contain around 20-25g of carbohydrates. It is possible to purchase low carb versions of the shakes too should you wish.

Carbohydrates are important for maintaining energy levels throughout the day, but there are good and bad carbohydrates.

Good carbohydrates are those like whole grains or fruits and vegetables. These are sometimes referred to as complex carbohydrates. Bad or ‘simple’ carbohydrates are processed and refined for easier digestion.

The latter are those included in Slimfast products.

It’s not the best option to consume simple carbohydrates on a regular basis for prolonged periods of time; they are damaging to health and can contribute to conditions like diabetes and heart disease. (13)


Of the many vitamins included in the formula, there is a large number of B vitamins, in particular : B1(thiamine), B2 (riboflavin), B3(niacin), B6 (pyridoxine), B7 (biotin) and B12 (cobalamin).

The vitamin B complex is vital for creating and absorbing energy from your diet.

Other vitamins included in Slimfast are vitamins A, C, E, D3 and K1.

Vitamin K1 plays a role in the clotting of blood; vitamin D3 is important for the adequate absorption of calcium, whilst vitamins A,C and E have antioxidant properties which help repair and defend cell tissue.


Alongside the variety of vitamins used in the Slimfast formula, there is also a selection of 10 minerals which are all vital for life.

These are magnesium, calcium, manganese, zinc, iron, chromium, iodine, molybdenum, phosphate and selenium. They each have their own crucial role to play in maintaining health.

Magnesium is used by the body for hundreds of different functions and reactions, it also maintains normal muscle and nerve function. (14)

Calcium is important for bone health. (15)

Zinc helps the body in several ways, most notably it supports the immune system and thyroid function. (16, 17)

Iron is critical for hemoglobin, which transports oxygen within the blood. (18)

Chromium has been shown to help manage blood sugar by intensifying the effect of insulin. (19)

Molybdenum has an essential role in enzyme metabolism. (20)

Iodine is critical for maintaining correct thyroid function and metabolism. (21)

Selenium has antioxidant properties and also supports the thyroid. (22,23)

Phosphate is used for bone formation. (24)

This combination of minerals is a fantastic addition to the Slimfast formula, helping you to get adequate nutrition whilst on the meal replacement plan.


It may seem counterintuitive, but Slimfast products do contain rather high quantities of sugar.

A combination of different sugars and sweeteners such as maltodextrin, fructose, sucralose, acesulfame potassium and corn syrup can be found in their shakes and snacks.

Sugar is very addictive and in fact it’s considered a harder habit to kick than that of cocaine. (25)

Side Effects

Even though Slimfast is a milkshake and snack program, unfortunately it doesn’t mean there is zero risk of side effects.

This said, the side effects we discovered while researching this Slimfast review were relatively minor.

There were a few reports of diarrhea, gas and bloating when using Slimfast which is uncomfortable but certainly not dangerous.

Recommended Dosage

Slimfast is a low calorie diet that is designed to be easy to follow. You can use just the shakes or a combination of their products should you wish.

You need to eat six times a day to keep the metabolism burning.

So you will replace two meals with a Slimfast shake, bar or other Slimfast meal replacement and then eat a sensible balanced meal for your third meal of the day.

In between each meal, you are allowed to have a 100 calorie snack. This can be a Slimfast snack or a piece of fruit, so long as it is 100 calories or less.

This standard SlimFast plan is created for women. However, men can also use Slimfast to lose weight. All they need to do is increase the meal replacement and snack intake by 200 calories.

Slimfast advise that you take 30 minutes exercise every day with Slimfast for best results.


Slimfast is a convenient, easy to follow low calorie diet plan centered upon the use of meal replacements.

We like how users are encouraged to eat regularly throughout the day, with a wide range of flavours and different snacks available to choose from.

The products are high in protein, vitamins and minerals to support lean tissue and overall health. But they also use artificial flavors and refined carbohydrates which are not healthy for use long term.

Furthermore, Slimfast can work out to be quite expensive, costing around $120 per month if you were to use the full product range as directed.

It’s also the kind of “diet” which does require a high level of willpower. Replacing food with a shake can sometimes prove to be harder to sustain than people realise.

Overall, providing users can manage to uphold the lack of real food in their diet, Slimfast is a good option for people who have a busy lifestyle and need an easy to follow plan. However, it’s by no means a long term solution.

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