Slimming World Syns: What Are They and What Do They Mean for Healthy Weight Management? (2023)

Either you've heard of Slimming World or someone you know has, at some point, mentioned the words 'Slimming World Syns' to you. A popular eating protocol to lose weight, before the Noom diet came along, Slimming World has been at the forefront of many people's minds for over a decade.

Now, following a year of fluctuating lockdowns and restrictions on our activity, you might be feeling the need to brush up on how to lose weight well – fair enough. Evidence suggests that it’s true that there has been an uptick in weight gain.

In a survey by King’s College London and Ipsos MORI which asked 2,254 people if they had gained weight during lockdown, 48% responded that, yes, they have (although, it is worth noting that there’s no way such a small survey could reflect the experiences of an entire nation of 68 million). And it makes complete sense; we’re generally less active and many have been feeling overwhelmed and stressed – both factors that can impact body weight.

But, as with all eating plans, it’s worth doing your research before signing up. No ifs, ands or buts. With that in mind, we looked into Slimming World – the eating plan and, specifically, those Slimming World Syns – and spoke to a registered dietician to help you get clued up before committing.

Before we continue, be aware, restrictive diets are also known to trigger eating disorders. ‘When people rely on external rules or diets to dictate their eating this removes the sense of autonomy and trust they have with their bodies. It is disempowering,’ says Rodriguez. ‘It gives the message that they cannot listen to their bodies rather they ‘must’ follow rules. The problem is, we are all so unique and our needs cannot all be met by the same cookie-cutter plan.’

If you, or anyone you know, is struggling with an eating disorder, contact Beat, the UK-based charity that hope to end the pain and suffering caused by eating disorders.
T: 0808 801 0677E:, under-18s:

What is Slimming World?

Slimming World is a diet that’s based on managing your intake of food through a kind of points system. The Slimming World eating plan, 'Food Optimising', doesn’t enforce calorie-counting, also known as calories in, calories out (CICO). Instead, foods and beverages fall into a number of categories, the core three being Free Food, Healthy Extras and Syns.

The idea behind this is to help people shift ‘shift from their old patterns of eating high energy-dense, less-satisfying food choices to eating a higher proportion of low energy-dense, satisfying and healthy foods, with the old favourites eaten in greater moderation,’ says Dr Jacquie Lavin, Nutrition and Research expert at Slimming World.

What are Slimming World Free Foods?

‘Free Food are foods that are most satiating and lowest in energy density (calories/gram),’ says Lavin. ‘There is a long list of Slimming World Free Food that are the essential ingredients in creating satisfying, tasty meals you can eat to fill up on.’ These include:

  • Lean meat and poultry
  • Fish
  • Eggs
  • Dried pasta
  • Rice
  • Potatoes
  • Fruit
  • Veg
  • Some fat-free dairy products (such as yoghurt)
  • Some meat replacements (like plain Quorn and tofu
  • Some store cupboard staples (like spices, herbs, and vinegar)

    ‘As long as they’re cooked without fat or oil, you can eat Free Foods with no weighing, no measuring, no limits and without having to count a single calorie or Syn,’ Lavin adds.

    What are Slimming World Healthy Extras?

    The second food category, Healthy Extras, includes “measured” portions of things. However, the name is somewhat misleading as Healthy Extras actually have Slimming World Syn values attached to them.

    • Milk and milk alternatives
    • Cheese and dairy-free cheese alternatives
    • High fibre cereal
    • Wholemeal bread
    • Nuts
    • Seeds

      What are Slimming World Syns?

      Put simply, Slimming World Syns are “treats,” or items you might eat or drink in moderation. Syns are what Slimming World calls its higher calorie and less nutrient-dense foods.

      ‘Syns are assigned to those foods that are least satiating and are high calorie, high fat and/or high sugar – foods like alcohol, crisps, chocolates or everyday essentials (a bit of butter, sauce or gravy with a meal),’ says Lavin. It's worth noting that “High” can be an objective term when we’re talking nutrients as we all have different requirements, but the NHS explains high-fat products as containing more than 17.5g of fat per 100g.

      (Video) SLIMMING WORLD DIET explained | How it works, Free food, Syns, Speed foods & Healthy Extras

      Any food that isn’t Free Food has a Slimming World Syn value attached to it, and dieters are allocated a number of Syns that they may redeem throughout the day.

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      How many Slimming World Syns can you eat per day?

      ‘To lose weight, most members are encouraged to have up to 15 Slimming World Syns a day,’ says Lavin. ‘Some Slimming World members, for example, those who have large amounts of weight to lose, may have a higher Syn allocation when they first join Slimming World.'

      Slimming World keeps tight-lipped about the formula it uses to calculate Syn values, but theorists suggest that the rule of thumb could be that 20 calories equate to 1 Syn.

      Another theory is fat content + carb content ÷ 5 = Syn value (the first theory would give a 45G bar of Cadbury Dairy Milk a Syn value of 12, and the second a Syn value of 8).

      Why are they called Slimming World Syns?

      'Slimming World Syns are so named because they are a way for members to guiltlessly enjoy the foods that many weight loss plans ban outright,' says Lavin. Though, we'd argue that the word "Syns" has negative connotations that can, indeed, trigger feelings of guilt.

      'Syns refers to the synergy between Free Foods, Healthy Extras and Syns, and it's these components that work together to make Food Optimising effective.'

      What are the best Slimming World low-Syn foods?

      Slimming World reserves its Syn values for members only, though a quick skim through Slimming World recipes would suggest that two slices of wholemeal bread count as 6 Syns and 30g Red Leicester cheese is also 6 Syns.

      (Video) Slimming World weigh day results// How I keep on plan

      It’s also thought, but not confirmed by Slimming World, that:

      • Honey = 2.5 Syns per tablespoon
      • Butter = 2 Syns per tablespoon
      • A Cadbury Freddo = 5 Syns per bar
      • Babybel = 3 Syns each
      • Red wine = around 4.5 Syns depending on serving size
      • White wine = around 6 Syns depending on serving size

        Should I try Slimming World?

        Whilst some Slimming World members have seen weight loss results, its method of categorising and labelling foods is likely not the most sustainable solution if you are looking to lose weight well.

        ‘When we adopt the idea or maintain the belief that foods are either good or bad, this distorts our relationship with food and eventually erodes the sense of trust we have with our bodies to tell us what to eat,’ says Ariana Rodriguez, Registered Dietician at Embody Health.

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        ‘Labelling foods as bad is often associated with an active effort to reduce our intake of these foods or with feeling a sense of guilt or distress once we eat them. Restrained eating studies show that when a restricted food is eaten, the more likely overeating takes place and the mere perception of breaking a food rule (such as eating a bad food) triggers overeating.'

        How to lose weight for good

        Your best bet (if you do want to lose weight, that is is to seek one-to-one advice from a compassionate registered dietician who can help you to figure out a sustainable, healthy and – importantly – enjoyable plan that suits you.

        If you do choose to try a diet plan like Slimming World’s, Rodriguez advises first considering whether the diet will get to the root cause of why you make your food choices or if it will simply act as a band-aid so you can see a smaller number on the scale.

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        ‘Rather than relying on external validation from a scale or dress size, what if you could cultivate internal validation?’ she asks. ‘I always like to do the one-year test with my clients and ask “can you see yourself maintaining this rigid structure for more than one year? Five years?” If the answer is no, the likelihood is that it is not sustainable.'

        So, that's the expert advice – develop a plan that works for you, your lifestyle and your unique set of needs. It might not look identical to the person's next to you but that's alright. Safe, sustainable weight loss is always the goal.


        What are SYNS in weight loss? ›

        Put simply, Slimming World Syns are “treats,” or items you might eat or drink in moderation. Syns are what Slimming World calls its higher calorie and less nutrient-dense foods.

        What does SYNS mean in Slimming World? ›

        'Sins' became 'Syns', which stands for 'Synergy' – and is how foods and drinks which are not part of the Free Foods or Healthy Extras sections, fit in with the Food Optimising plan.

        How many SYNS can I have for my weight? ›

        Another fantastic thing about Food Optimising is that no food is banned. The key is moderation, which is why alcohol and foods that are high in fat or sugar have a Syn value. Slimming World members are encouraged to plan 5-15 Syns a day to keep their weight loss on track, without feeling like they're missing out.

        What is the meaning of SYNS? ›

        ' Although Syns sound like something a little bit naughty, the word is actually short for 'synergy', because the diet plan relies on the synergy of Free Foods, Healthy Extras and Syns in order to lose weight healthily. The best way to think about Syns is as the little extras that you can enjoy alongside a healthy diet.

        How many SYNS are in a banana? ›

        And remember that a whole banana is 0 syns, and has a calorie content of 90 calories? Well a Muller Light also used to be 0 syns, and also has a calorie content of 90 calories.

        Can I use all my SYNS and still lose weight? ›

        You can eat lots of free food to fill you no need for extra syns. The amount of syns only makes a difference when you count the calories of your food. If you are eating low calorie things then 30 syns wont matter. If you are stuffing your face with potato and pasta then 30 syns will make all the difference.

        What can I eat syn free on Slimming World? ›

        Slimming World Free Foods include:
        • lean meat (and meat replacements)
        • fish.
        • eggs.
        • rice.
        • pasta.
        • potatoes.
        • beans and lentils.
        • vegetables.

        How do you calculate Slimming World SYNS? ›

        Using Your Slimming World Syns Calculator

        Once you're a paying member of Slimming World, either online or in person, you'll get access to the official online calculator. Just type in your favourite foods, and you'll get up to date and accurate details on how many Syns that food has.

        What fruit is SYN free on Slimming World? ›

        Pretty much all fresh and frozen fruit is free. Cooked, canned and dried fruit are categorised under Healthy Extras and puree fruit, any fruit juices or smoothies are classed as Syns.
        Examples of Free Fruit:
        • Apples (S)
        • Bananas.
        • Blackberries (S)
        • Blueberries.
        • Clementines (S)
        • Grapes.
        • Grapefruit (S)
        • Kiwi Fruit.
        Jan 20, 2017

        How many SYNS are in an avocado? ›

        30g (1oz) of avocado is just 2 syns and I've discovered that most small avocado, when cut in half, are around the 45g (1.5oz) mark. Which is 3.5 syns and not that hefty amount of syns you thought it to be? You should be weighing just the flesh, as you are not eating the stone or the skin.

        How do I maximize my weight loss on Slimming World? ›

        Here are some simple strategies to ensure you get a great weight loss in your first week:
        1. Understand how to make changes to your eating habits. ...
        2. Follow a flexible eating plan. ...
        3. Start cooking from scratch. ...
        4. Swap takeaways for fakeaways. ...
        5. Eat less fatty and sugary foods. ...
        6. Realise you're not alone. ...
        7. Stay to group every week.

        How do you count SYNS? ›

        20 Calories = 1 Syn.

        How many free foods can you eat on Slimming World? ›

        Slimming World members love that they can eat Free Foods in unlimited amounts – with no counting, weighing or measuring needed – until they feel full.

        How many calories is 15 SYNS? ›

        So now 1 syn = 90 calories. We all know that an avocado is 14 syns, and an avocado contains 320 calories, so 14 syns = 320 calories. But wait, remember our mashed banana that's 5 syns and 90 calories? Well, if we ate 3 mashed bananas that means 15 syns = 270 calories.

        Can you really eat as much pasta on Slimming World? ›

        At Slimming World, we don't believe in cutting out food groups. In fact, potatoes and dried plain pasta, rice, noodles and couscous are all Free Foods, which means that you can eat as much of them as you like!

        How many eggs can you eat on Slimming World? ›

        Eggs are one of Slimming World's 'Free Foods' so you can eat as many as you like on its Food Optimising healthy eating plan. Slimming World says Free Foods like eggs are 'filling and low in calories for their weight'.

        How many SYNS is 2 eggs? ›

        Eggs. Boiled, scrambled, fried, poached, or baked, eggs are a syn-free option making them perfect for breakfast, lunch, and dinner.

        How many SYNS are in an apple? ›

        Please note: You do not need to Syn pureed, blended or mashed vegetables. Apple, cooking 100g – 1.5 (375g can be a Healthy Extra B) Apple, eating 100g – 2.5 (250g can be a Healthy Extra B) Fresh Apricots 100g – 1.5 (450g can be a Healthy Extra B)

        Why is my weight loss so slow on Slimming World? ›

        Your weight loss will partly depend on your starting point and how much you have to lose, it is slower as you get nearer to target because a thinner body requires fewer calories to maintain weight. Average for me is about 1 - 1.5 per week with occasional higher amounts for weeks were I may have been more active.

        What is the average weekly weight loss on Slimming World? ›

        As the Slimming World diet is based on healthy eating, you can expect to lose, on average, 2lb a week. Exercising regularly will boost this weight loss.

        What happens when I reach my target weight at Slimming World? ›

        We offer free maintenance sessions to members once they have reached their personal achievement target and stay within ± 3lbs of this agreed weight.

        What foods are SYNS? ›

        The foods that are least filling and are higher in calories, like biscuits, sweets and alcohol, count as Syns at Slimming World. Enjoying a little of what you fancy — like a piece of chocolate or a glass of wine — means you won't be tempted to go off track.

        How many SYNS is 100 calories? ›

        100 Calories is the equivilant of approx. 5 Syns.. It might not sound much but if you can burn 100 calories per day or around 3 times a week you will find that it aids your weight loss in a massive way.

        How many SYNS is 320 calories? ›

        So now 1 syn = 90 calories. We all know that an avocado is 14 syns, and an avocado contains 320 calories, so 14 syns = 320 calories. But wait, remember our mashed banana that's 5 syns and 90 calories? Well, if we ate 3 mashed bananas that means 15 syns = 270 calories.


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