Does Slimming World Work? Here’s What You Need To Know

woman holding waist line of loose jeans

If you’re in the UK and looking at starting a new diet, chances are you’ve heard of Slimming World. You’re probably wondering whether it works and also how does Slimming World work?

I’ve spent years with Slimming World. Many of my 1-to-1 clients use or have tried the plan as well. This means I am in a good position to answer.

My Slimming World Experience

Slimming World gets a bit of a reputation for being another unrealistic or fad diet.

I’m critical of some of the plan but, I would not be anywhere near as healthy as I am now without Slimming World.

I grew up obese. From the age of around 15-16, I tried crash diets and crazy exercise routines. I tried weight-loss teas and pills as well. And nothing worked. When I was 19, I fell upon Slimming World by chance.

I met someone after a 4-month gap where they lost something like 30 pounds.

And off I went to my local Slimming World group.

I’ll save the ups and downs for another post, but in my time with Slimming World I lost around 90 pounds. I went on to lose around another 50 pounds on my own afterward. This was when I started exercising and started learning more about nutrition.

Does Slimming World Work?

But my point is Slimming World gave me a structure and a plan which I could stick to, which suited me, and gave me a foundation to start from. And for me, as a result, it worked.

How Does Slimming World Work?

The plan options Slimming World offer have changed substantially since I was with them but at their core, they remain roughly the same:

  • Unlimited (yes, you read that right) amounts of certain foods – namely fruits, vegetables, some lean proteins, low-fat dairy,

  • Fixed portion options for some foods. This includes some other carbs, healthy fats, and some other dairy and protein options,

  • Anything else. If something doesn’t fit into one of the above categories, you can still have it but it gets assigned a ‘syn‘ value. You’re allowed up to a certain number of syns in a day or over a week.

No food is banned or off-limits but those syns can stack up quickly.

If you focus on the foods you can have in unlimited amounts (aka ‘free’ foods), you don’t ever really need to weigh or measure your portions.

It sounds wild but the reason it works is that these foods are predominantly low or very low in calories and very high in nutritional value.

So I guess you could say Slimming World‘s “trick” is to get you to focus on highly nutritional, lower-calorie foods.

This means you move away from foods that have more calories in them.

As a result, you will usually end up eating better, often eating fewer calories than you were before, and this can lead to weight loss.

The Pros Of Slimming World

Less Measuring

If you don’t want to measure or count portions of everything, this would suit you perfectly. Free or unlimited foods are your best friend here.

Better Nutrition

Slimming World focuses on improving your nutritional quality. And it helps you to maximise your vitamin and mineral intake – which is going to give you a massive health boost.

Simple To Follow When You Get The Gist

The above rules may seem pretty complicated. But actually, when you get the gist of it, it’s pretty straightforward. Unlimited amounts of some foods, track and measure the others.

HUGE Online Community

And let’s not forget one of the biggest factors. There is a HUGE online community if you don’t enjoy the weekly in-person meetings. 

To give you some idea of scale, #slimmingworld on Instagram has more than 27 million posts. By comparison, #weightwatchers has 9.8 million posts. 

So to say the Slimming World online community is big is probably still an understatement.

The Cons


There are a few loopholes in how the plan is laid out. 

For example, while fresh fruit when eaten whole is free, if you mash it, it has a syn value. The theory is that it is digested much more quickly so will make you hungry again soon.

I find that a bit questionable. You still chew your food so it still is mashed by the time it reaches your stomach.

But let’s apply that in real life. If you’ve used up your syns for the day, you wouldn’t be able to have 1 mashed banana. But you would be ok to have as many whole ones as you wanted.

slimming world whole and mashed banana

These kinds of loopholes are a little bit troublesome in making the plan easy to follow, but they’re not by any means catastrophic.

Food Terminology

Calling foods “free” foods is a little bit problematic. Where many people who are looking to lose weight, some portion control is helpful for keeping your results long-term

This is one of the reasons people who lose weight with Slimming World regain it. Understanding of portions hasn’t happened. And now it is being applied to less nutritious foods.

More unsettling though is labeling foods as “syns“. I’m not keen on demonising food and changing the spelling from sin to syn doesn’t undo the impact of associating foods with that word.

cat enjoying snacks gif

This does tie in with portion control. You understand what a portion of a specific food is, you compare that to your body’s needs, and you act accordingly.

Body “Magic”

I get that exercise can be intimidating and scary for a lot of people.

Slimming World is in a unique position. It can help people who really need support and guidance in finding balance with exercise. 

Referring to exercise as ‘body magic’ might have a nice ring to it. I remember when I first started exercising it was nice to be able to say I did some body magic (not sexy slang…).

It is great to get Slimming World members started with increasing their activity but there’s no progression. It’s not factored into plans so the health benefits of physical exercise beyond weight loss can get lost.

Emphasis On Weight

I feel conflicted about mentioning this. But weight is just one measure of progress and only one measure of health. 

But with Slimming World it is the only – or at least the predominant – measure of progress. 

Week-to-week weight fluctuations are erratic and can vary massively. Using that as your measure of progress can lead to a lot of stress and emotion.

But you step on the scales and that is the most important thing in the world.

It won’t sell quite as well as promoting just weight loss. But it is still something I’d love to see Slimming World emphasise a bit more in their message.

Will Slimming World Work For You?

If you’re asking does Slimming World work, then yes it does for a lot of people. Whether it works for you though is down to the foods you enjoy, lifestyle, eating habits, budget, and more.

What I will say though is that if you switch your nutrition and food intake to focus on foods that are high in nutrients, like Slimming World encourages, then even ignoring weight loss, your overall health will be a lot better.

It’s something you can do with or without Slimming World. But for some, that structure and community make all the difference.