Slimming World: What are Syns (2023)

Slimming World is one of the most popular diets in the UK, known best for its Syns – a range of 'treats' with a carefully calculated Syn value, which you can only eat so many of. Here's how Syns work on the Slimming World diet ...

This page contains affiliate links, which means we may earn a small amount of money if a reader clicks through and makes a purchase. All our articles and reviews are written independently by the Netmums editorial team.

If you're eager losing weight you've no doubt heard of the hugely popular Slimming World diet, and you may be trying to get your head around it. There are definitely a few things you'll need to master if you want to get the most out of this particular weight loss and lifestyle plan – for example, what on earth are Syns?

Two very important components of the Slimming World diet are Syns and Free Foods.

In a nutshell:

• Syns are what Slimming World calls 'treats'.
• Free Foods you can eat as much (or as little) of as you wish.

So let's get you clued up on everything there is to know about Slimming World's Syns ...

What are Slimming World Syns?

Slimming World Syns are 'treat' foods that contain lots of calories, but not much nutrition. It's fine to enjoy Syns in moderation, but they shouldn't form a large part of your diet.

Carolyn Pallister, Public Health Manager and Dietitian at Slimming World, further describes Syns as:

'The foods that are least filling and higher in calories, like biscuits, sweets and alcohol. 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.'

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. They shouldn't be a main part of your diet, but what would life be if we couldn't enjoy a little treat from time to time? That's the beauty of the Slimming World diet plan; although it encourages you to eat healthily, and it still allows a little of what you fancy.

How many Syns can I have each day?

The exact number of Syns you can have each day will depend on your specific Slimming World diet plan, but it's usually between 5 and 15 Syns. However, you can have as many free foods as you want!

Members following the Extra Easy SP plan (a diet plan designed to further boost weight loss) are advised to enjoy around 10 Syns each day. In general, the fewer Syns you have, the more weight you're likely to lose!

As an example, a 125ml glass of Prosecco is 5 Syns, while chocolate can be anything from 5 Syns – like a Freddo bar – to around 13 Syns for a Mars bar – depending on which type you're eating.

Other examples of Syns foods are biscuits, cakes, crisps, dressings, ice cream and pizza. Plus, don't forget that little added extras, such as honey and butter, also have a Syn value.

If you join the Slimming World plan, you'll easily be able to find out the Syn value of any given food. You can also find plenty of info and tips from people following the plan, plus general diet advice and support in our friendly forum.

(Read to the end of this article to find out what other people are saying about Slimming World and Syns.)

How are Syns calculated?

Syns are designed to help make people make healthier choices. That's why some foods have a lower Syn value than others.

Syns are calculated by Slimming World using a combination of:

• calorie content
• how filling they are
• if they contain Free Foods

So foods with lots of calories that aren't very filling (like chocolate and alcohol) will usually have a high Syn value. There is an entire booklet listing Syn values for the majority of foods – including branded foods.

If you can't find the Syn value this way, you can work out a rough value using the calories. One Syn equals around 20 calories so, if you have a crumpet that's around 100 calories, it will hold a Syn value of five.

What are the most popular low-Syn foods?

Some foods have a lower Syn value than others, meaning you can 'treat' yourself on the Slimming World plan without going over your daily Syn allowance.

Popular low-Syn foods include:

• Mug Shots, between 1 to 5.5 Syns depending on the flavour.
• Ice poles, between 0.5 and 1 Syn depending on the brand.
• Hi-Fi Bars, 3 Syns each.
• Curly Wurlys, 6 Syns.
• Options Hot Chocolate sachets, 2 Syns.
• Hula Hoop Pufts, 3.5 Syns per bag.
• Freddo, 5 Syns per bar.
• A crumpet, between 2.5 to 5 Syns depending on brand.
• Soreen Malt Loaf Lunchbox Loaves, 4.5 Syns.
• Babybel, 3 Syns each.
• Hartley's 10 Calorie Jelly Pots, 0.5 Syns each.
• SkinnyPop popcorn, 4 to 5 Syns per bag, depending on the flavour.
• Alpen Light cereal bars, between 3 and 6.5 Syns, depending on the flavour.
• Quavers, from 4.5 syns per 17g bag to 9 Syns per 34g bag.

Other commonly enjoyed Syns include:

• Honey, 2.5 Syns per tablespoon.
• Avocado, 14 Syns per average avocado
• Pesto, about 3.5 Syns per tablespoon (depending on the brand). Reduced fat pesto can be as low as 1.5 Syns per tablespoon.
• Butter, 2 Syns per teaspoon, or 5.5 Syns per tablespoon (less for low-fat spreads)
• Rice cakes, from 1.5 Syns for a large plain rice cake, to 4 Syns or more for a chocolate-covered rice cake, depending on the brand.

Syns in drinks

Many drinks also have a Syn value – you'll be surprised how high some of them are!

• Starbucks Mocha Frappuccino, between 13.5 and 20.5 Syns, depending on size and which milk you choose.
• Costa Full Fat Latte, between 7 and 13 Syns depending on size.
• Full fat Coca Cola, 7 Syns per 330ml can.
• Diet Coca Cola, zero Syns.
• Lemonade, between 2 to 5 Syns per 100ml (but sugar-free lemonade has zero Syns).
• Coconut milk, from about 4 Syns per 100ml for reduced-fat versions, to 8 Syns per 100ml for full-fat versions.
• Gin and slimline tonic, roughly 4 Syns per measure of gin (slimline tonic is Syn-free).
• Red wine, around 4.5 Syns, depending on the size of your glass.
• White wine, around 6 Syns, depending on the size of your glass.
• Rose wine, around 6 Syns, depending on the size of your glass.
• Koppaberg cider, 4.5 Syns per 250ml.

Why not buy yourself a diet planner to help you get organised? This planner is designed to work with the Slimming World diet and is available here at Amazon. It has pages to log weight-loss, track your goals and even motivational tips.

Changes to Syns

Back in 2018, there was some controversy over Muller Light Fat Free yoghurts, which had always been considered a Free Food (more on this below). Following some changes to the plan they're now no longer Free Foods and instead count as one Syn each.

At the time of the change, people on the plan weren't happy, because these yoghurts were used as a 'guilt-free' dessert to satisfy a sweet tooth, without adding to daily Syns.

This popular yoghurt wasn't the only food to be removed from the Free Food list after Slimming World realised users were eating them in large quantities.

Other former Free Foods that now hold a Syn value include:

• Tinned pasta shapes in tomato sauce (all brands and varieties) are now half a Syn per 100g.
• Instant mashed potato (all brands and varieties) is now three and a half Syns per 100g.
• Danone Activia 0% Fat (any flavour) is now one Syn per 125g pot.

So if you're coming back to Slimming World after a break, you may find that the Syn values of certain foods aren't quite what you remembered – always double-check the official Slimming World advice for the latest information.

In a statement about the changes to the plan at that time, a Slimming World spokesperson said:

'Our Nutrition team routinely review our Food Optimising eating plan to ensure it’s up to date, in line with the latest guidance, and to take into account feedback from our 5,000 Consultants and 900,000 Slimming World members.

'As part of this process, we’ve been looking at how to give our vegan members more choice, and we’re delighted that a number of vegan foods, including canned jackfruit and plain and unsmoked seitan, can now be enjoyed freely by slimmers following our plan.'

The spokesperson added:

'In addition, a number of products – fat-free flavoured yogurts, tinned pasta shapes in tomato sauce and instant mashed potato – that were previously Free on our plan, meaning they could be eaten without weighing, counting or measuring, will now have a small Syn value.

'This is because some of these foods are often eaten in large amounts, as a 'snack' rather than being enjoyed as part of a meal, or because they’re less satisfying than alternatives, such as mashed potato made with fresh potatoes.

'As the new Syn values are still so low, Slimming World members can easily still include them within their daily choices, if that's what they choose to do, and fat-free natural yogurts, dried pasta and potatoes will continue to be Free.'

You can also buy recipe books to help you plan what you eat.The Slimming World Free Foods cookery book has over 120 recipes and is available here at Amazon.

Slimming World reviews and 'Syns' tips

We scoured the Netmums Forum to find out what our readers are saying about Slimming World and Syns ...

'The slimming world plan does work, i have been going to group for over a year and seen people shrink before my very eyes. It is not unusual for people to lose a couple of stone in their first 6-10 weeks.'
– Anonymous

'To maximise losses on sw; Make sure you're actually eating enough, don't fall into trap of your body going into starvation mode, Include speed foods as much as possible (...) keep variety in snacks etc. When I did it, got to point where it felt like I'd scream if I saw another muller light lol. Sign up to pinch of nom page, on Facebook. They have a weekly post of new sw friendly foods/recipes etc'
– emma p(413)

'Look up something called the 'whoosh' effect, it explains why we may lose weight then maintain! We just have to carry on doing as we're doing and it'll start working! It can be really disheartening can't it?? When I got on the scales and it said a 2lbs gain I nearly cried!! I'd said the week before in group I wanted to lose 3, and couldn't face staying to group and explain why I'd weirdly put on 2lbs with no explanation?! Anyway, it has transpired today that it was AF! Which since giving birth gives me no warning - no cramp or mood swings so will have to start keeping track of my cycle!'
– Laura P(1379)

'Stick with it and just make sure you write a diary and give it to your consultant to make sure you are not doing anything you shouldn't and stay to group. If you are doing it all correctly then you should see a difference soon. I made the mistake of thinking avocados were free when they weren't and spent a few weeks at the same weight before I realised! Also I think some low-fat yoghurts have syns so do double check in the book or use the online tool, I found that great!'
– Anonymous

'How can people say this works?? I've tried and followed plan and have gained 3lb! I eat ryvita and boiled egg for breaky. Lunch is jacket pot beans salad. Dinner is curry or sausage mash ! I snack on fruit fruit fruit and I do eat choc a day and crisps, seems to be in Syns though. Can anyone tell me their plan their exact eating plan for a week and if I can follow it please.
Also, doctors claim too much red meat is bad for you and causes heart disease yet SW says eat as much as you want??'
– Anonymous

'You need to aim for around 10 syns a day and eat loads of superfree - oranges. strawberries, spinach etc. Why not go to group for a couple of weeks - i can't lose weight unless i go!!!'
– Lowri W(8)

'I've not tried it myself, but someone told me if your stir a sachet of options hot choc into a tub of fat free yog (presumably a large tub!!), you get a choc mouse for 1.5syns!!!'
– Anonymous

'(Sin-free treats) Have you tried the Alpen light bars chocolate and fudge? I tried one for the first time today and it was really nice, and you can have 2 as a 'b' healthy extra. Also sugar free jelly and frozen mullerlight (I can pretend I'm eating ice-cream lol)'
– Bethan L(7)

'I lost 4 stone last year and put 1.5 stone back on, and have now lost another. Breakfast - 2 slices of toast from 400g loaf (whole meal) with marmite or fat free yogurt and fruit. Also have fruit on side of plate if I have toast. Or hi fi bar and fruit. Lunch most days Batchelors pasta n sauce or low fat super noodles with a big salad. Tea normally meat done on BBQ and salad and jacket potato. Every day I have a mini magnum as my syns (9 syns).'
– Anonymous

'I've lost half a stone so far on the extra easy plan, and I haven't been following it all that strictly to be honest! I'm not good for eating breakfast but when I do I have scrambled eggs and bacon or an omelette with bacon in it. For lunch I have a Mug Shot or Supernoodles or rice with veg and for tea: Chicken stuffed with Philadelphia Light Garlic & Herb and wrapped in bacon with all visible fat removed, new potatoes and veg. Pasta with ham, sweetcorn and a philly sauce. Turkey and Bacon Hotpot. Lean pork fillet in a Philly mushroom sauce with veg and roast potatoes made with Fry-lite. Syn free chips are lovely too.'
– Anonymous

Want more tips on Slimming World, including practical ideas on how to keep within your Syns limit? You can always get advice and suggestions by visiting our forum, below.

Related stories

Does Slimming World really work?

CHAT: Slimming World, what have you eaten today?

Healthy eating hacks for busy mums