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: help@beateatingdisorders.org.uk, under-18s: fyp@beateatingdisorders.org.uk

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.

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.

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.

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.

‘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.

‘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.