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Keto SlimFast – Fuel Shakes & Snacks Review

We’ve probably all heard of SlimFast here in the UK. If not, to summarise it’s a popular diet plan where you eat their own branded shakes and snacks, along with 1 low-calorie meal per day. In the past, SlimFast was just focusing on low-calorie foods but they do have a range of shakes & snacks that are specifically for keto!

Product range

The SlimFast Keto product range consists of three shakes and 1 snack. They are designed to be eaten as part of a healthy keto lifestyle and should not be eaten just by themselves.

Traditionally, SlimFast plans require you to replace two meals with shakes, as well as snacks. However, for their keto range, their plan is a bit different and they recommend you supplement (not replace) your meals with these products.

If you’re restricting your calories to lose weight, then the shakes might be a good idea as they are all under 202 calories.


There are 3 flavours to choose from, for the sake of completeness, I purchased all three to try from Amazon.

Rich Chocolate

SlimFast Advanced Keto Fuel Shake Rich Chocolate

Everybody loves chocolate, right? This was the one I was most excited to try, as I just can’t get enough chocolate in my life. The shakes say to mix with water but I decided to use unsweetened almond milk so that it would be a bit thicker.

Note – only 10 servings per 350g container

Each serving (35g) is mixed with around 200ml of liquid. I popped it all in a tall glass and used a milk frother to mix it all together.

Nutritional information per serving

Energy: 199kcal, Fat: 15g, Carbs: 3.8g, Fibre: 3.0g, Protein: 9.5g, Salt: 0.43g

At 3.8g of carbs per serving, it’s not a particularly insane amount of carbs but is more than I thought it would be. However, even if you had two shakes a day you would still have over 10g leftover for dinner (based on 20g carbs per day).

Taste & Texture

With the milk, the texture was surprisingly thick, not as thick as a milkshake but still pretty good! As for the taste, it’s very chocolaty and doesn’t have any chemical aftertaste. Which for many on the keto diet, they know how common that problem can occur!

Overall, I liked it but it didn’t fill me up as much as I thought it would. With 15g of fat and 9.5g of protein per serving, I don’t know if I would call it a meal replacement. Though to be fair, SlimFast is calling these Fuel Shakes not meal replacements.

Rating: 8/10 – could be more filling and less carbs.

Creamy Vanilla

SlimFast Advanced Keto Fuel Shake Creamy Vanilla

You can always play it safe with vanilla. Don’t get me wrong I like vanilla, it’s just that its a bit plain but can act as a great base where you can add more flavour. Maybe some blueberries or peanut butter could enhance this one?

As before, I mixed this with almond milk instead of water to give it the best possible chance of wowing me.

Nutritional information per serving

Energy: 199kcal, Fat: 16g, Carbs: 3.7g, Fibre: 0.6g, Protein: 10g, Salt: 0.35g

Compared to chocolate it has a tiny bit more fat and fewer carbs but shockingly fibre is only 0.6g compared to 3g. Don’t know if that is a mistake or the ingredients differ that much.

Taste & Texture

The texture is the same as chocolate, I might try these with the recommended water but I’d imagine it may be way too thin.

On the other hand, the taste is quite surprising. I was expecting a weak subtle flavour but was pleasantly surprised with a taste more akin to ice cream. Again, no chemical taste and I devoured the whole thing really rather quickly, so it must have been good.

Rating: 7/10 – slightly below chocolate due to lack of fibre (and well, not being chocolate)

Smooth Mocha

SlimFast Advanced Keto Fuel Shake Smooth Mocha

Coffee and chocolate? Sounds like a good pairing but I often find coffee flavoured products to taste a bit too artificial. Let’s see about this one.

Nutritional information per serving

Energy: 202kcal, Fat: 16g, Carbs: 4.4g, Fibre: 2.6g, Protein: 9.5g, Salt: 0.35g

The highest calorie and carb count out of all three. At 4.4g of carbs per serving, that seems rather high but maybe the flavour makes up for it.

Taste & Texture

Hmm, after my first sip I quite liked it. I wasn’t overpowered by the coffee and you could really taste the chocolate. However, as I drank more, it left me with a bit of an aftertaste in my mouth. It wasn’t unpleasant but not something I would buy again. I know some will love it but it’s just not for me and for that reason I’m out.

Rating: 5/10 – not a fan of the flavour pairing and aftertaste


At the time of writing, there is only 1 snack available in the SlimFast keto range. I purchased a 12 pack off Amazon at a reasonable price.

Nutty Caramel Keto Fuel Bar

SlimFast Advanced Keto Fuel Bar Nutty Caramel

Remember the days when you could raid the vending machine at work and get your favourite chocolate bar? Luckily, this seems to be a pretty good alternative at only 5.0g of carbs per 46g bar.

It doesn’t contain any maltitol or other problem sweeteners and instead uses stevia and erythritol. In other words, you shouldn’t expect to be kicked out of ketosis or experience any GI issues.

As with all keto-friendly snacks they aren’t the cheapest and you’ll be looking to spend over £2 a bar, which brings them into a similar price range of protein bars.

Nutritional information per serving

Energy: 200kcal, Fat: 15g, Carbs: 5g, Fibre: 15g, Protein: 8g, Salt: 0.38g

Admittedly, 2g of the carbs is polyols, so you could subtract that from the net carbs as it will not be digested. Bringing the total down to only 3g of carbs per bar!

Taste & Texture

For a caramel bar, I didn’t find it overly sweet which was a welcome surprise. It has nice nutty taste & crunch but it is rather chewy. No chemical aftertaste and is rather filling because of all the kinds of butter used (read more about that in the next section). Great as a treat and would buy again.

Rating: 8/10 – would buy again, though maybe wait for a deal!

Is SlimFast Keto really Keto?

Short answer: Yes

Longer answer:

There are many product ranges that are marketed towards the keto lifestyle and while most are indeed keto-friendly some are not.

Many products contain bulking agents and sweeteners like maltitol, that can spike your blood sugar and kick you out of ketosis (read more).

SlimFast keto shakes use sucralose and other keto-friendly ingredients as their sweeteners. For the fat portion, MCT, avocado and coconut oil powder is used which are great keto fat sources.

As for the flavourings, this is what increases the carb count. For chocolate and mocha, fat-reduced cocoa powder is used which can contain around 8g of carbs per 100g (on average). The vanilla flavour uses vanilla bean powder but only a small amount (0.1%).

In addition, the shakes have added vitamins B6 & B12, which are reported to contribute to maintaining a healthy metabolism.

Putting that all together, you can see that some thought has actually gone into the ingredients to make them keto-friendly. A+ for effort!

Lastly, we have the caramel keto fuel bar that contains 5g of carbs. As a snack that isn’t too bad and so long as you aren’t eating multiple per day, they can be great as a snack on the go.

Ingredients wise, it does contain palm oil but is from a certifiably sustainable source. The sweetener is erythritol & stevia which are some of the best for keto. Inulin is also used which works great in combination with erythritol as it has a warming effect to counter the cooling effect of the erythritol.

As with the shakes, MCT oil powder is used for the fat source along with cocoa, sunflower seed and peanut butter. This helps in making you feel fuller for longer.

As an added bonus, all the products are suitable for vegetarians but not vegans as they contain milk derivatives.

What do you mix SlimFast Keto shakes with?

The directions on all the shakes say to mix a single serving with 200ml of water but you can use milk if you would prefer a thicker shake. You could also add ice cubes to make it last longer.

On SlimFast’s own site, they state:

SlimFast Keto Fuel Shakes are designed to be made up with water and not milk to ensure you get all nutrients in the right amounts for a Keto diet. However you can choose to make them with a milk of choice if you would like a creamier shake.

Of course, your choice of milk will affect the carb count. The best keto-friendly milk is unsweetened almond milk, though other low carb options are available. Check out our article on that here.

Dairy milk is high in carbs so best to avoid that altogether!

What is SlimFast Keto good for?

So what is the product range targeted towards? It’s not really a total meal replacement plan like their other products. I would say they’re more for supplementing your keto lifestyle for when you’re too busy to prepare a meal or are on the go.

Examples could include:

Work – have a shake for lunch at work and save preparing a healthy meal beforehand. You could keep the snack bars in your desk for a quick afternoon treat (or maybe as an elevenses).

Gym – shake could be great as a post-gym drink but it might be better to look at a protein shake if you’re doing any strength or resistance exercises.

Ease of use – if you’re not a keen cook, keto can be difficult. These shakes could help alleviate that by replacing maybe one or two of your meals. However, if you’re not looking to lose weight then I would avoid them due to their low-calorie count.

Where to buy

You can find the SlimFast Keto range both online and in UK stores.


The complete range can be purchased from Amazon, the shakes are also available on Subscribe & Save which can save you between 5 and 15% per order. Also, look out for vouchers for a percentage of your first subscribe & save order for these products.

Creamy Vanilla

SlimFast Advanced Keto Fuel Shake Creamy Vanilla, 320 g

Available at: Amazon

Rich Chocolate

SlimFast Advanced Keto Fuel Shake Rich Chocolate 350g

Available at: Amazon

Smooth Mocha

SlimFast Advanced Keto Fuel Shake Smooth Mocha, 350

Available at: Amazon

Nutty Caramel Fuel Bar

Available at: Amazon


Keep an eye in out in Superdrug & Boots for offers, as I’ve seen the shakes discounted before! You can find all of these in the health and beauty aisles.

Creamy Vanilla ShakeAsda, Boots, Superdrug

Rich Chocolate ShakeAsda, Boots, Superdrug

Smooth Mocha ShakeAsda, Boots, Superdrug

Nutty Caramel Fuel BarAsda, Boots, Superdrug

Product alternatives

Branded keto products can be expensive and other alternatives are available that can be much much cheaper!

For the shakes, you could perhaps use a protein powder instead. The carb count would be drastically lower (depending on flavour). I would recommend a whey protein isolate powder as it contains the fewest carbs and then add your own flavours.

Check out our article on the best low carb protein powders for more information and ideas.

Good keto snacks can be hard to come by, especially ready-made ones that don’t have to be kept in a fridge. If you have an Aldi near you, then I would wholeheartedly recommend you try their Dark Chocolate & Nut Bars with Sea Salt. At only 6g of carbs per bar, they are perfect as treat and they won’t break the bank!

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