How Many Syns In Slimfast Shake? & Other Low Syn Shakes!

Updated on 
9 March, 2026

Are Slimfast MilkShakes High In Syns?

Slimfast is a well-known brand in the diet industry, they are great for producing low calories snacks and shakes, but since these foods are not syn free, you need to ensure your track them.

The Slimfast shakes tend to have between 10-11 syns a shake, making them very high in syns, the value depends on the shake flavour that you choose. 

In our small guide below, we will discuss what makes Slimfast shakes so high in syns, the syn values of their whole shake range as well a few low syn alternatives, we have also included a friendly slimming world smoothie to have as an alternative!

Why Are Slimfast Shakes So High In Syns?

Slimfast shakes are high in syns due to the fact they contain skimmed milk powder which contributes to the calories, they are aimed to be a meal replacement rather than as a drink.

On the slimming world plan, we would avoid having these shakes due to them being so high in syns and having little nutritional benefits in comparison to having an actual meal.

Syn Values Of The Slimfast Shake Range

Slimfast shakes come in a few different flavours so do vary slightly in syns, we've listed the values of their whole range below.

  • Slimfast Chunky Chocolate Shakes - 10 syns.
  • Slimfast Cafe Latte Milkshake - 10 syns.
  • Slimfast Vanilla Milkshake - 10 syns.
  • Slimfast Strawberry Flavour Shake 365G - 11.5 syns.
  • Slimfast Chocolate Flavour Shake 375G - 11.5 syns.
  • Slimfast Vitality Vegan Strawberry & Blueberry 400G - 11 syns a serving.
  • Slimfast Advanced Keto Fuel Shake Creamy Vanilla 320G - 10 syns a serving.
  • Slimfast Banana Milkshake Multipack 6X325ml - 10 syns.
  • Slimfast Vitality Vegan Intense Mint Chocolate 432G - 11 syns.

Low Syn Shake Alternatives

If you like meal replacement shakes as a way to lose weight then you might be interested in checking out some of the low syn alternatives we've listed below.

  • Tesco Slim Chocolate Meal Replacement Shakes 10X29g - 10 syns.
  • Tesco Slim Vanilla Meal Replacement Shakes 10X29g - 10 syns.
  • Tesco Slim Banana Mealrepl. Shake 10X29g - 10 syns.
  • For Goodness Shakes Recovery Milk Chocolate 475Ml - 14.5 syns.
  • For Goodness Shakes Protein Strawberry 475Ml - 10 syns.
  • Ufit Chocolate Orange Protein Milkshake 330Ml - 8 syns.
  • Up&Go Energize Breakfast Shake Chocolate 400Ml - 11 syns.
  • Mighty Shake Banana & Oat 330Ml - 3 syn per 100ml.
  • Mighty Shake Chocolate 330Ml - 2.5 syns for 100ml.
  • Cambridge Diet Meal Replacement Shakes - 10 syns.

Our SW Friendly Smoothie Shake Recipe

If you love a shake or a smoothie but don't want to waste so many syns on them, we've put together a slimming world smoothie recipe below which will only cost you two syns.

Ingredients

  • 200ml of milk (can be used as healthy extra a).
  • Two mint leaves.
  • A small banana.
  • Raspberries.
  • Sweetener.

Method

  1. Start by placing everything in a blender and pulse till a smooth consistency then serves with ice!

Last Words

Overall, Slimfast shakes have between 10-11 syns depending on the flavour that you choose making them very high in syns, you would need to save nearly your whole daily syn allowance to consume one. As a lower syn alternative, we would suggest checking out other shakes above or making your own SW friendly 2 syn version!

Frequently Asked Questions

How are syn values calculated?

Syn values are calculated using a formula based on calories, saturated fat and sugar content per serving. They’re not the same as calories — a product can be low in calories but higher in syns if it’s high in sugar or fat. Always check the official Slimming World app for the most accurate and up-to-date syn values.

Do syn values change?

Yes. When manufacturers reformulate their products, the syn value can go up or down. This is why we recommend double-checking with the Slimming World app or your consultant, especially if a product’s packaging has changed recently.

How many syns should I have per day?

Most Slimming World members work with 5 to 15 syns per day. Your consultant will advise on the right amount for you. The key is to use your syns on the things you enjoy most — whether that’s a chocolate bar, a glass of wine, or a packet of crisps.

Jennifer
Jennifer is a certified nutritionist and weight loss coach with a Master's in Nutrition from Cambridge. With over 10 years experience, she shares healthy recipes and science-backed slimming tips on SheCooksSheEats to help people reach their wellness goals. Jennifer stays up-to-date by regularly attending conferences and continuing her nutrition education. She aims to provide research-backed advice to inspire balanced, happy living.
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