...information for health professionals

Dietary Approach - Food Optimising

Food Optimising is Slimming World’s healthy eating plan. Based on the principles of energy density and satiety, Food Optimising empowers members to make healthier food choices, satisfy their appetites and lose weight – without calorie counting or obsessive weighing and measuring it is a life-long healthy eating plan.

Food Optimising is easy to follow, focusing on three main components:

  1. The concept of Free Foods promotes consumption of plenty of low energy dense and highly satiating foods, eg poultry, fish, lean meat, pasta, grains, vegetables and fruit, which can be eaten without restriction. Members are encouraged to use these foods to satisfy their appetite while reducing overall energy intake. With Free Foods members don’t have to monitor every mouthful – so compliance is easy to establish and sustain.
  2. Healthy Extras help provide a good overall balance of nutrients in addition to those obtained from Free Foods, with particular emphasis on calcium and fibre-rich foods, eg milk, cheese, cereals and wholemeal bread.
  3. The synergy between Free Foods, Healthy Extras and Syns makes Food Optimising effective and easy to live with long term. Syns are the way members can enjoy the foods that many diets ban – without a shred of guilt! Counting Syns helps members naturally limit consumption of saturated fats, alcohol and sugar, ie those foods with a high energy density and poor ability to satisfy hunger.

The science behind Slimming World's Food Optimising

Research has shown that the nature and composition of the foods we eat, dietary macronutrients and energy density, impact on our sense of satisfaction and fullness (satiety) 1. Encouraging a higher intake of more satiating foods will limit energy intake and result in weight loss. Slimming World has been actively involved in this field of research and, along with the Scottish Office, sponsored research conducted by Dr James Stubbs at the Rowett Research Institute. There is now a robust evidence base which shows that foods higher in protein and carbohydrates are far more satiating than foods rich in fat 2 3.

Research also shows that people feel full due to the amount of food they eat, not the number of calories they take in. Choosing low energy dense foods can increase the volume of food eaten, while reducing energy intake, and thus satisfy appetite 4.

A study led by the University of Leeds found that participants who consumed low energy dense meals (based on Slimming World’s recipes) felt significantly more full and less hungry than those eating high energy dense meals, despite consuming the same number of calories 5. Those who followed a plan based around Slimming World meals for 14 weeks, lost significantly more weight than those calorie-counting over the same time period (6.2% body weight compared to 3.8%). Those following the Slimming World plan also reported increased feelings of control around their food choices and a greater confidence in their ability to stick to their weight-loss plan.

Since its inception in 1969, Food Optimising has always successfully embraced the scientific principles of appetite regulation and energy density in a practical way to regulate energy intake, allowing members to eat unlimited amounts of highly satisfying foods, which will naturally help limit calorie intake without the chore of counting or feeling deprived.

A balanced approach

Through the structure of Free Foods, Healthy Extras and Syns, Food Optimising provides a flexible and practical weight loss plan while also encouraging a balanced approach in line with current healthy eating guidelines.

Food Optimising promotes a reduction in fat, particularly saturated fat, and the inclusion of at least five portions of fruit and vegetables per day alongside starchy carbohydrates and lean protein-rich foods to satisfy the appetite. Measured portions of fibre and calcium-rich foods are included on a daily basis.

All major food groups are encouraged in line with the Eatwell Guide1 and health notes guide members in following current Government recommendations on healthy eating.6 :

Eat well guide

Around 88% of the Eatwell Guide is made up of a combination of fruit and vegetables, starchy carbohydrates like rice, pasta and potatoes, and protein rich foods such as lean meat and fish, all of which are Free Foods within Food Optimising. A smaller section of the guide is for milk and dairy. Food Optimising classifies milk and cheese as 'Healthy Extras', and encourages those following the eating plan to enjoy daily measured portions as they are good for overall health. The smallest purple section and those foods outside of the main image are foods that are high in fat and/or sugar - these are Slimming World's controlled Syns.

Realistic and flexible, Food Optimising:

    ✓ takes into account individual needs and preferences
    ✓ adapts to all lifestyles, cultures and budgets, and is suitable for all the family
    ✓ encourages slimmers to feel free and relaxed about food, eliminating the distress caused by feelings of guilt, hunger, deprivation and loss of control
    ✓ enables members to take control of their own health and lifestyle for the long-term
    ✓ doesn't ban foods or food groups
    ✓ doesn't use expensive or specialist 'diet' products

Our research

Various research7 8 9, including that conducted by the British Nutrition Foundation, has found that members consume a diet that more closely meets UK dietary guidelines than the average UK adult. On average, members:

  • eat more fruit and veg than the general population and exceed the five-a-day recommendation
  • meet the recommended calcium intake
  • eat more fibre than the general population and are more likely to meet the recommended daily intake
  • consume less sugar, fat and saturated fat than the general population
  • have less salt than the general population (in line with the recommendation of no more than 6g/day)
  • eat more oily fish than the general population
  • cook from scratch more often since joining and more frequently than the general population
  • now have takeaways/fast food less often
  • reduce their units of alcohol soon after joining and meet the recommended guidelines of <14 units of alcohol per week

Research also shows that members following Food Optimising have an average percentage energy intake of 47% from carbohydrates, 23% from protein and 27% from fat9.


  1. Stubbs, J., Whybrow, S. and Lavin, J. 2010. Dietary and lifestyle measures to enhance Satiety and Weight Control. Nutrition Bulletin, 35: 113-125.
  2. Weststrate, J.A., et al. 1992. Effects of nutrients on the regulation of food intake. Unilever Research: The Netherlands: Vlaardingen.
  3. Stubbs, J., Ferres, S., and Horgan, G. 2000. Energy density of foods: Effects on energy intake. Critical Reviews in Food Science and Nutrition. 40(6): p. 481-515.
  4. Ello-Martin, J.A., et al. 2007. Dietary energy density in the treatment of obesity: a year-long trial comparing 2 weight-loss diets. American Journal of Clinical Nutrition. 85(6): 1465-1477.
  5. Buckland N J et al. 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 Nutrition May 1;148(5): 798-806.
  6. NHS choices. The Eatwell Guide. Available from: http://www.nhs.uk/Livewell/Goodfood/Pages/the-eatwell-guide.aspx
  7. Avery A., Toon J., Kent J., Holloway L., Lavin J., Bennett SE. 2021. Impact of COVID-19 on health-related behaviours, well-being and weight management. BMC Public Health 21, 1152.
  8. Strathearn L, Kaçar HK, 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 23(12): 2189-2198.
  9. Coe, A. Spiro, S. Lockyer and S. Stanner 2019. Ensuring a healthy approach to long-term weight management: Review of the Slimming World programme. British Nutrition Foundation Nutrition Bulletin, 44, 267-282

Food Optimising incorporates scientific understanding of how foods affect our appetite and translates these principles into a way of eating that is practical for use in today's world, so members can lose weight without restriction or deprivation.

Dr James Stubbs, Obesity Research Specialist

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