Slimming World Diet Guide: How To, Benefits + Drawbacks

Analyzing the global weight loss phenomenon.

The Slimming World diet encourages lifelong healthy eating behaviors by instilling an approach to balanced eating.

One of the main appeals of the Slimming World Diet is that although it promotes eating mostly healthy, nutritious food, it doesn’t restrict a long list of specific things you are not allowed to eat. It also allows for the occasional indulgence, which makes it easier to follow.

In this diet guide, we will discuss how to follow the Slimming World diet, its principles, and potential benefits and drawbacks so you can decide if it’s right for you.

Let’s jump in and see if it works!

A person showing weight loss by pulling the waist band of her jeans.

What Is the Slimming World Diet?

The Slimming World diet is an eating plan that was developed in Great Britain about 50 years ago by Margaret Miles-Bramwell. It has since become popular in the United States and other countries worldwide.

While the Slimming World diet can support weight loss, it is also designed to be a lifelong approach to eating rather than a short-term crash diet for rapid weight loss.

This means that even once you have reached your ideal body weight, you can follow the Slimming World diet plan for weight maintenance, using the same framework and principles while adjusting for higher caloric needs.

While there aren’t any specific foods that are banned on the Slimming World diet meal plan, you are encouraged to eat the most nutritious food choices such as vegetables, fruits, whole grains, low-fat dairy, lean proteins, nuts, seeds, and healthy fats.

However, you are also allowed to enjoy “indulgences“ occasionally without feeling like you have “cheated“ or broken the rules of your diet and derailed your weight loss goals.

Ultimately, the Slimming World diet program is a realistic, sustainable, and smart approach to weight loss and weight management and may increase adherence.1De Leon, A., Roemmich, J. N., & Casperson, S. L. (2020). Identification of Barriers to Adherence to a Weight Loss Diet in Women Using the Nominal Group Technique. Nutrients12(12), 3750. https://doi.org/10.3390/nu12123750

A variety of colorful fruits and vegetables

How Does the Slimming World Diet Work?

The Slimming World diet is built around a weight loss and management concept known as Food Optimizing.

This is essentially the same thing as the volumetrics diet in that you want to focus your meals and snacks on filling foods such as vegetables, fruits, lean proteins, and starchy veg and then add smaller amounts of higher-calorie foods such as whole grains and dairy.

Then, occasionally, you can have treats or “junk food” when you crave it.

Proponents of the Slimming Life Food Optimizing approach to weight loss suggest that this encourages you to fill up on nutrient-dense but not calorically-dense foods while having the “permission“ to enjoy special treats without feeling like you have broken your weight loss meal plan rules.

This built-in flexibility with the Slimming Life meal plan is intended to help decrease shame and anxiety surrounding having “bad foods“ while trying to lose weight and is supposed to alleviate some of the problems often seen with overly restrictive weight loss diets.2Koliaki, C., Spinos, T., Spinou, Μ., Brinia, Μ.-E., Mitsopoulou, D., & Katsilambros, N. (2018). Defining the Optimal Dietary Approach for Safe, Effective and Sustainable Weight Loss in Overweight and Obese Adults. Healthcare6(3), 73. https://doi.org/10.3390/healthcare6030073

A salad.

‌To improve adherence, the Slimming World Group also offers weekly online or in-person support groups (in select locations).

There are also workouts (called Body Magic), and exercise is encouraged as part of your overall healthy approach to weight loss or weight management.

There are different Slimming World diet membership levels, with each tier providing different levels of support with an increasing price structure for each level.

Online membership packages cost between $63–84 for three months, depending on the level that you select.

After the three-month kick-off portion of the Slimming World diet program, you have to pay $26 per month to continue.

How Do You Follow the Slimming World Diet Plan?

To start with the Slimming World diet program, you must sign up online in the U.S. or U.K. Slimming World diet website.

Then, you will receive more information about the Slimming World Food Optimizing principles, which are summarized below.3Welcome to Slimming World’s Food Optimising plan – a new way of eating. (n.d.). Slimming World. https://www.slimmingworld.co.uk/what-can-i-eat

Basically, when you are constructing a Slimming World diet meal, you want to follow the three steps of Food Optimizing in order, which will help you create a healthy meal for weight loss or weight management.

A salad and cherries.

#1: Fill up on “Free Food”

Free Food Should form the bulk of your plate.

According to the Food Optimizing plan, Free Food can be enjoyed in unlimited amounts without getting measured, weighed, or worried about due to the high nutrient density and low-calorie content.4Buckland, N. J., Camidge, D., Croden, F., Lavin, J. H., Stubbs, R. J., Hetherington, M. M., Blundell, J. E., & Finlayson, G. (2018). A Low Energy–Dense Diet in the Context of a Weight-Management Program Affects Appetite Control in Overweight and Obese Women. The Journal of Nutrition148(5), 798–806. https://doi.org/10.1093/jn/nxy041

‌No calorie counting here!

#2: Add Measured Healthy Extras

Although you don’t need to measure the Slimming World diet Free Food, the next step is the healthy extras intended to be measured.

These foods are higher in calories but still provide essential nutrients.

For example, some of the Slimming World diet’s healthy extras are milk and cheese, which are good sources of calcium; whole-grain bread and whole-grain cereals for fiber and other B vitamins; and nuts and seeds for healthy fats and oils.

A person eating a donut.

#3: Enjoy a Few Syns

Finally, Slimming World Syns are high-calorie foods that don’t offer much in the way of nutrition.

Although Syn foods sound like “sin foods,” Syns is actually short for Synergy.

These foods work synergistically with the diet because they help prevent feeling deprived and help you keep a balanced perspective about eating; it’s OK to enjoy your favorite treats occasionally in moderation, even when you are trying to lose weight.

Examples of Slimming World diet Syn foods are cookies, chocolate, alcohol, chips, etc.

The Slimming World diet app and website provide Slimming World diet recipes and lists of Slimming World Food Optimizing foods for each of the three food categories.

The Food Optimizing System aims to help you construct nutritionally balanced meals without needing to count calories and worry about what foods you cannot eat, as there are no foods that are off-limits entirely.

Then, Slimming World members are encouraged to attend weekly virtual support meetings for in-person meetings if there is one in your area.

The meetings are an opportunity to not only have social support from other members who are also on their own weight loss journeys but also to have a source of accountability, ask questions, and identify self-limiting behaviors that are serving as obstacles to reaching your weight loss goals.

A person exercising.

What Are the Benefits of the Slimming World Diet for Weight Loss and Health?

Several studies suggest that the Slimming World diet plan for weight loss can be successful.5Stubbs, R. J., Pallister, C., Whybrow, S., Avery, A., & Lavin, J. (2011). Weight Outcomes Audit for 34,271 Adults Referred to a Primary Care/Commercial Weight Management Partnership Scheme. Obesity Facts4(2), 1–1. https://doi.org/10.1159/000327249

In fact, one large-scale Slimming World diet study of 1.3 million adults who attended weekly support meetings in the UK found that dieters who attended at least 75% of the Slimming World support group sessions lost an average of 7.5% of their initial weight in the first three months of the program.

This is quite impressive.

Consider someone who weighs 200 pounds.

If he or she loses 7.5% of 200 pounds in three months, the new body weight would be 15 pounds lighter, or 185 pounds.

This is actually a safe and sustainable rate of weight loss because losing 15 pounds in 12 weeks is just over 1 pound per week.

According to the Centers for Disease Control and Prevention, a safe and sustainable rate of fat loss is between 1 to 2 pounds per week for most adults.

It also speaks to the benefit of building weekly support group sessions into the program.

A person showing weight loss by pulling the waist band of her jeans.

Another Slimming World diet weight loss study found that participants lost an average of nearly 20 pounds or 10 kg over six months if they attended at least 20 out of 24 Slimming World diet meetings.6Stubbs, R. J., Brogelli, D. J., Pallister, C. J., Whybrow, S., Avery, A. J., & Lavin, J. H. (2012). Attendance and weight outcomes in 4754 adults referred over 6 months to a primary care/commercial weight management partnership scheme. Clinical Obesity2(1-2), 6–14. https://doi.org/10.1111/j.1758-8111.2012.00040.x

‌Keep in mind that while these Slimming World diet weight loss results and success stories are indeed impressive, the studies were conducted by the Slimming World diet company, so there may be some bias built into the methodology and results.

In addition to Slimming World diet weight loss results, studies have found other Slimming World diet benefits in terms of adopting healthier dietary habits and lifestyle behaviors in general.

For example, the Slimming World diet program has been found to help people increase their intake of dietary fiber while significantly decreasing their consumption of simple sugars and refined grains.7Strathearn, L., Kaçar, H., & Avery, A. (2020). Changes in dietary patterns when females engage in a weight management programme and their ability to meet Scientific Advisory Committee on Nutrition’s fibre and sugar recommendations. Public Health Nutrition, 1–10. https://doi.org/10.1017/s1368980019004762

Other studies have found that people who follow the Slimming World diet develop a greater preference for healthy foods than when they started the program and have found better ways to incorporate daily physical activity into their lives.8Pallister, C., Avery, A., Stubbs, J., & Lavin, J. (2009). Influence of Slimming World’s lifestyle programme on diet, activity behaviour and health of participants and their families. Journal of Human Nutrition and Dietetics22(4), 351–358. https://doi.org/10.1111/j.1365-277x.2009.00959.x

Other studies have found that the Slimming World diet plan can improve health markers such as decreasing BMI, decreasing hemoglobin A1c levels (an indication of long-term blood sugar control), and improving other risk factors for cardiovascular disease and obesity.9Avery, A., Griffin, J., Stokes, J., Coulton, R., Pallister, C., & Lavin, J. (2019). The benefits of non‐surgical weight management on weight and glycaemic control in people with complex type 2 diabetes: A primary care service evaluation of clinical outcomes at 12 months. Endocrinology, Diabetes & Metabolism2(2), e00045. https://doi.org/10.1002/edm2.45

A scale.

What Are the Drawbacks of the Slimming World Diet?

‌While there are many benefits of the Slimming World diet plan for weight loss and health, there are a few drawbacks.

The Slimming World diet plan is fairly expensive and has ongoing fees.

Most of the evidence suggests that to reap the benefits, you have to attend the weekly group meetings, which can be time-consuming and generally have to be virtual for most people unless you live in an area with in-person Slimming World plan support groups.

It can also take time to understand the Food Optimizing framework and master Slimming World diet recipes that satisfy the Slimming World diet Food Optimizing plan.

Does Slimming World Work?

Overall, the Slimming World diet is certainly one of the best healthy weight loss plans and helps instill lifelong healthy behaviors while still being realistic with the need to have the freedom to enjoy special treats within the larger context of a well-balanced meal plan.

If you are still shopping around for a diet and would like to try out the point system, check out our guide to Weight Watchers here.

Remember, when looking for the perfect eating style for your needs, working with a nutritionist is always ideal to find the best option.

References

  • 1
    De Leon, A., Roemmich, J. N., & Casperson, S. L. (2020). Identification of Barriers to Adherence to a Weight Loss Diet in Women Using the Nominal Group Technique. Nutrients12(12), 3750. https://doi.org/10.3390/nu12123750
  • 2
    Koliaki, C., Spinos, T., Spinou, Μ., Brinia, Μ.-E., Mitsopoulou, D., & Katsilambros, N. (2018). Defining the Optimal Dietary Approach for Safe, Effective and Sustainable Weight Loss in Overweight and Obese Adults. Healthcare6(3), 73. https://doi.org/10.3390/healthcare6030073
  • 3
    Welcome to Slimming World’s Food Optimising plan – a new way of eating. (n.d.). Slimming World. https://www.slimmingworld.co.uk/what-can-i-eat
  • 4
    Buckland, N. J., Camidge, D., Croden, F., Lavin, J. H., Stubbs, R. J., Hetherington, M. M., Blundell, J. E., & Finlayson, G. (2018). A Low Energy–Dense Diet in the Context of a Weight-Management Program Affects Appetite Control in Overweight and Obese Women. The Journal of Nutrition148(5), 798–806. https://doi.org/10.1093/jn/nxy041
  • 5
    Stubbs, R. J., Pallister, C., Whybrow, S., Avery, A., & Lavin, J. (2011). Weight Outcomes Audit for 34,271 Adults Referred to a Primary Care/Commercial Weight Management Partnership Scheme. Obesity Facts4(2), 1–1. https://doi.org/10.1159/000327249
  • 6
    Stubbs, R. J., Brogelli, D. J., Pallister, C. J., Whybrow, S., Avery, A. J., & Lavin, J. H. (2012). Attendance and weight outcomes in 4754 adults referred over 6 months to a primary care/commercial weight management partnership scheme. Clinical Obesity2(1-2), 6–14. https://doi.org/10.1111/j.1758-8111.2012.00040.x
  • 7
    Strathearn, L., Kaçar, H., & Avery, A. (2020). Changes in dietary patterns when females engage in a weight management programme and their ability to meet Scientific Advisory Committee on Nutrition’s fibre and sugar recommendations. Public Health Nutrition, 1–10. https://doi.org/10.1017/s1368980019004762
  • 8
    Pallister, C., Avery, A., Stubbs, J., & Lavin, J. (2009). Influence of Slimming World’s lifestyle programme on diet, activity behaviour and health of participants and their families. Journal of Human Nutrition and Dietetics22(4), 351–358. https://doi.org/10.1111/j.1365-277x.2009.00959.x
  • 9
    Avery, A., Griffin, J., Stokes, J., Coulton, R., Pallister, C., & Lavin, J. (2019). The benefits of non‐surgical weight management on weight and glycaemic control in people with complex type 2 diabetes: A primary care service evaluation of clinical outcomes at 12 months. Endocrinology, Diabetes & Metabolism2(2), e00045. https://doi.org/10.1002/edm2.45
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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