Slimming World Under the Spotlight
Slimming World Diet Review

Slimming World has been around for nearly 50 years and has some impressive success statistics. Dietitian, Juliette Kellow BSc RD reviews the Slimming World diet and gives us her verdict.

Slimming World Diet Under the Spotlight

By Dietitian Juliette Kellow BSc RD


Slimming World is certainly a big name in the diet industry and with an almost 50-year history it has apparently stood the test of time. Margaret Miles-Bramwell created Slimming World and the original diet in 1969 and remains the chairman of the organisation today.

Decades on and Slimming World has around 4,500 consultants and over 16,000 groups in the UK. They’re impressive statistics and so it would seem the Slimming World diet certainly works.

But just what does the Slimming World diet entail and can it help you keep the weight off afterwards? We delve deeper…

How Does The Slimming World Diet Work?

Slimming World is basically a slimming club that combines a unique diet plan with group support. To gain access to the diet, you need to become a member.

You can also become a Slimming World online member and receive the diet information this way.

Tell Me About the Slimming World Diet?

Slimming World’s unique plan is called Slimming World Food Optimising.

The theory behind the plan is simple – to lose weight you need to take in fewer calories than you use up.

Slimming World Food Optimising achieves this reduction in calories by encouraging dieters to freely eat foods that are lower in calories but high in nutrients such as pasta, lean meat, rice, fish, fruit and veg, whilst limiting calorie-packed foods that are nutrient-poor such as biscuits and booze.

This is essentially the same as the WLR Plan – it focuses on reducing calories and eating more healthy foods. However WLR does not set limits on any foods and instead encourages you to educate yourself on your food choices, rather than being told what to eat.

Because the focus is on eating mainly lower-calorie foods, Slimming World claims that its Food Optimising diet lets you eat as much 'free food' as you like.

You only have to count Syns in restricted foods rather than counting the calories for everything you eat.

This means there's less weighing and measuring. However, this lack of focus on how much you eat means that you are unlikely to learn about portion sizes and calories and could easily revert to your old ways of eating.

All the information about Slimming World Food Optimising is provided in a book that’s part of the joining pack you receive when you become a member.

So How Does Slimming World Food Optimising Actually Work?

The diet has three steps:

Step 1 – Choose Free Foods

Slimming World provides detailed lists of foods that can be eaten in unlimited quantities. Fresh fruit and most veg are classified as Speed Foods because they are so low in calories.

Free Foods include lean meat, chicken, fish, potatoes, rice, pasta, grains, pulses, starchy veg, eggs, fat-free dairy products, Quorn and tofu.

Within Free Foods, there are three choices available: the Extra Easy choice; the Green choice (sometimes known as a Green Day); or the Original choice (a Red Day).

You can mix and match these choices from one day to another or simply stick to the same one all of the time.

Step 2 – Choose Healthy Extras

In addition to Speed and Free Foods, you are allowed Healthy Extras every day.

These vary according to whether you are following the Extra Easy, Green or Original plan.

Step 3 – Choose Syns

Syns is shorthand for synergy – Slimming World believes it’s the synergy between the three components of the plan, ie. Free Foods, Healthy Extras and Syns, that makes Food Optimising effective at enabling weight loss.

Nevertheless, many of the Syns are effectively what other diet plans would call ‘treats'.

But Syns also includes foods found in the Healthy Extras, allowing you to eat bigger portions of these foods if you want them.

Regardless of the plan you choose to follow, you are allowed five to 15 Syns a day.

These include foods like biscuits , cakes, crisps, dressings, alcohol, ice cream, preserves, puddings, pizza, chocolate and sweets.

The Syns value for some foods may vary depending on the plan you are following but as a guideline one Syn is equivalent to around 20 calories.

In contrast, wlr doesn’t encourage you to associate any food with negativity. Rather, simply eat the foods you like in proportion to your calorie needs

You can try the wlr tools free here.

What Can I Eat With the Slimming World Extra Easy Choice?

You start by filling a third of your plate with Speed foods - fruit and veg, then add unlimited amounts of foods from the following:

  • beans
  • peas
  • lentils
  • bulgur wheat
  • couscous
  • potatoes
  • pasta
  • noodles
  • rice
  • eggs
  • Quark
  • fat-free cottage cheese
  • natural fromage frais and natural yoghurt
  • Quorn
  • tofu
  • lean meat
  • poultry
  • offal
  • fish.

On top of this you choose one Healthy Extra from the A choices, which are mainly calcium-rich dairy products.

For example, a choice is 350ml skimmed milk, 28g Cheddar or 42g mozzarella.

Plus, you choose one Healthy Extra from the B choices, which tend to be higher in fibre and include wholegrain cereals, crispbreads and bread, dried, cooked and canned fruit, and filling soups.

For example, a choice is one wholemeal pitta, two slices of wholemeal bread from a small loaf, 28g wholegrain cereal or 71g dried apricots. Then you have your Syns on top of this.

What Can I Eat With the Slimming World Green Choice?

The Green choice focuses on more carb-rich foods and less meat, so is a better choice for people who follow a vegetarian diet.

Once again you start by choosing Speed Foods and then add unlimited amounts of Green Free Foods, as mentioned above, minus the meat and fish products.

You choose one or two Healthy Extra A choices (low-fat dairy products) and two Healthy Extra B choices, the list of which is extended to include lean meat, poultry, fish, nuts, seeds and more cheeses.

For example, a choice is 57g cooked beef, 71g cooked chicken, 142g cod, 28g Edam or 28g houmous. Syns are added on top of this.

Unlike wlr, you are restricted in what you eat, in the sense that you follow certain plans provided for you. This could limit your flexibility on the plan, especially if the diets don’t suit you.

Slimming World doesn’t educate you in calories which, when it comes to make healthy choices, is what really counts.

If you decide to leave Slimming World, you may struggle to keep your weight off in the long-term without having learned about calories and portion sizes.

What Can I Eat With the Slimming World Original Choice?

The Original choice focuses on more lean protein-rich foods and fewer carb-rich foods.

You start by filling up on Speed Foods then add unlimited amounts of Red Free Foods, which include:

  • lean meat
  • poultry
  • fish
  • eggs
  • fat-free natural yoghurt
  • fromage frais
  • cottage cheese
  • Quorn
  • tofu.

You choose one or two Healthy Extra A choices (low-fat dairy products) and two Healthy Extra B choices, the list of which is extended to include beans, lentils, wholewheat pasta and potatoes.

For example, a choice is 142g baked beans, 100g cooked wholewheat pasta or a 227g baking potato (raw weight). Syns as always, are added to this.

Isn’t This a Version of Food Combining?

No. Food combining doesn’t allow carbohydrate- and protein-rich foods to be eaten in the same meal.

Whichever plan you follow on the Food Optimising programme, you are still allowed to eat carbs and proteins in the same meal – it’s just that you might eat smaller amounts of one or the other in order to help you lose weight.

What are the Pros?

Food Optimising basically encourages healthy eating by recommending lots of fruit and veg, healthy carbs, lean protein-rich foods, low-fat dairy products and smaller amounts of fatty and sugary foods.

The theory is that whilst losing weight, members develop good eating habits they can follow for life – that will help to keep the weight off.

There’s also no need to cook different meals for yourself – all the family can eat meals based on Slimming World’s Food Optimising plan.

The concept of Syns also helps to educate slimmers on those foods that are higher in fat and sugar and so should be limited – but at the same time allows them in small amounts so they don’t feel deprived.

It’s also good to see that exercise is considered to be an integral part of the programme.

And the Cons?

All of the Free Foods such as lean meat, chicken, fish, pasta, potatoes, rice, couscous, eggs and beans still contain calories.

For example, with the Easy Extra choice, in theory you could eat a spaghetti Bolognese designed for four people providing it only included Free Food ingredients such as wholewheat pasta, lean mince, carrots, onions, mushrooms, canned tomatoes, tomato puree and stock. This could easily add up to 2,000+ calories (a large portion of wholemeal pasta contains 400 calories alone)!

As a result, it’s possible to eat sufficiently large amounts of Free Foods to take in enough calories to cause weight maintenance or even weight gain rather than weight loss.

Though Food Optimising claims there’s not much measuring needed, you’ll still need a pair of accurate food scales as all the Healthy Extras and Syns are given in weighed amounts.

Unfortunately, most of the weights aren’t in consumer-friendly amounts either, for example, 57g of cooked pork, 71g canned salmon or 113g chickpeas. You’ll need very accurate scales that measure to 1g to get this level of accuracy.

Juliette’s Verdict

As a newcomer to the plan, the diet seems very complicated and incredibly daunting. You need to spend time working out exactly what you can eat freely and get to grips with the Extra Easy, Green and Original choices, together with the Healthy Extras and Syns.

Fortunately, there’s a 7-day plan based on the Extra Easy choice to help you out.

Food Optimising

I like the fact Food Optimising encourages a healthy, balanced diet and doesn’t ban any foods.

However, whilst I support the concept of limiting fatty and sugary foods, I do think using the term Syns has a negative meaning within a plan that is otherwise very positive.

Syns might stand for Synergy but the term still infers that certain foods are ‘sinful’ and therefore reinforces the idea that they are ‘naughty’ or ‘bad’ for us. As a result, we are more likely to feel guilty when we’ve eaten them – something that contradicts Slimming World’s mission to promote guilt-free eating.

Free Foods

When it comes to the claim that you can eat as much as you like, for successful weight loss, it’s important not to take that to the extreme.

Indeed, if some people did eat as much as they liked of the Free Foods, they could potentially end up gaining weight rather than losing it.

This means you still need to exert some degree of control when it comes to serving sizes, no matter what the Slimming World literature says.

Like many health experts, I think it’s crucial that people start to have a better understanding of what constitutes a suitable portion size to help them control their weight.

This includes portion sizes for foods like meat, pasta, rice and potatoes. For example, a suitable portion of meat should be about the size of a deck of cards, a portion of rice or pasta should be about the size of a tennis ball, and a potato should be about the size of a computer mouse.

Slimming World does nothing to educate slimmers about the sort of portion sizes they should really be aiming for, potentially making it more difficult for slimmers to keep the weight off once they start to relax their diet a little more and include more ‘Syns’.

Household Measures

As for the foods that need to be weighed, I would prefer to see more household measures being used, or at least guidance on weighed portions to the nearest 10 grams. This is far more practical.

No Magic Wand

All in all, there’s no magic behind the Slimming World diet. Ultimately, it’s a plan that helps you to reduce your calorie intake so that you shift those pounds.

Whether or not you want group support to help you on your way is a personal thing – whilst some people benefit massively, others may shy away from the idea of talking about their weight problem with others.

In conclusion, as wlr members will already know, to shift those pounds you need to change your eating habits and focus on eating healthy, nutritious and lower-calorie foods whilst having fewer fatty and sugar foods.

Slimming World’s Food Optimising plan has the potential to help you achieve this, providing you can get to grips with what you can and can’t eat and remember that Free Foods still contain calories and so shouldn’t be eaten in supersized amounts.

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