What effects does it have?

What is it?

Reducing body fat by changing what you eat.

How long does it last?

The effects of dieting only last while you maintain the diet. For dieting to be successful, it needs to be a sustainable permanent lifestyle change.

More information

You may be interested in losing body fat to reduce chest, hip or buttock size, to make muscles more defined, or to prepare for medical procedures. A number of UK surgeons who perform gender related surgeries require people to have a body mass index (BMI) below a certain threshold before they will operate.

Weight loss can be confusing because there are many different types diets promoted by many different organisations.

While there are many diets that suggest changing the amount of carbohydrate (“carbs”), protein, or fat in your diet or cutting out certain foods, there currently isn’t any clear medical evidence for any of these diets being better than just reducing calories 1. Given this, the current recommendations in the UK 2 and elsewhere 3 are to reduce your calorie intake while ensuring you are doing regular exercise.

Do not attempt to radically reduce calories by eating extremely small amounts unless you have been told to do so by a doctor.

So that you are confident that your hard work will be successful, you may wish to use the diet recommended by the NHS and the British Dietic Association and available on the NHS website.

It is worth talking to your GP about weight loss, as they may be able to refer you to local NHS services for managing weight loss and your lifestyle.


  1. 1 Sacks, Frank M, Bray, George A, Carey, Vincent J, Smith, Steven R, et al. (2009) “Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates.” N Engl J Med, 2009(360), pp. 859–873.
  2. 2 National Institute for Clinical Excellence (2014) “Obesity: identification, assessment and management (CG189).” [online] Available from: https://www.nice.org.uk/guidance/cg189
  3. 3 Jensen, Michael D, Ryan, Donna H, Apovian, Caroline M, Ard, Jamy D, et al. (2014) “2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults.” Circulation, 129(25 suppl 2), pp. S102–S138.

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Page last updated: September 2017