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How to lose weight fast and treat diabetes: all you need to know about the Very Low Calorie Diet (VLCD)

very low calorie diets

The Very Low Calorie Diet (VLCD) is a diet of less than 800 calories a day for a maximum of 12 weeks, according to NICE guidelines (10). These calories are made up mostly of protein with some carbohydrates and fats (5). All of this is consumed mostly in the form of liquid shakes made from milk, soy or egg-based powder with water, though some may include soups and bars (5). 

Similar diets have been around since the 1970s with Oprah Winfrey toting her 70-pound weight loss from a liquid diet in the 1980s (5) but the VLCD was only officially approved for medical use in the UK since 2006 (10). Other diets include the Cambridge diet (now called 1:1 diet) and the 800 calorie diet which similarly restrict calories. 

Whilst there are many commercial low-calorie shake replacements available right now, the Very Low Calorie Diet is currently being trialled for provision on the NHS (2) – so you could be prescribed the diet by your own GP!

Is the VLCD suitable for me?

The VLCD is an extreme diet. For perspective, a caffe mocha at Starbucks is half the daily calories allowed in the VLCD program.

The recommended daily caloric intake is 2000kcal for women and 2500kcal for men (4). For this reason, it is only suggested for people that class as obese (over 30 BMI – you can test your BMI yourself at home!). And this diet should not be undertaken without advice and support from your doctor. 

Benefits of the VLCD: will I lose weight? Will it cure my diabetes?

Various studies have shown significant weight loss benefits in groups of people on the VLCD diet especially in the short term, measured at the end of the diet (7, 8, 9, 10, 2). One study in Sweden summarising many findings found that those on a VLCD program had much greater weight loss at the end of the diet than people that just undertook a less extreme low calorie diet which is 1200-1500kcal per day (9).  Another trial run by diabetes UK recorded an impressive 15kg weight loss across the group one year after their Very Low Calorie Diet! (2) 

Some newspapers have reported that these diets can ‘cure’ diabetes – but is this true? 

Some studies have shown that people with type 2 diabetes (the one that is acquired with age and is influenced by your diet) the VLCD can effect their glucose levels! Insulin is a hormone which controls the glucose in your body which energises your cells and your body, but this does not function properly in type 2 diabetes. Various studies on diabetics have found that this diet can improve insulin functioning and even lead to a remission from diabetes completely! For instance, in one study from Thailand, 79% of people had normal blood glucose levels by the end of the diet (7) whilst another reported 40% returned to normal glucose levels (4). 

But these studies were all done with very few people, and many have been classed as low quality by NICE (10), so they may not be as reliable as the weight loss data!

Risks of the VLCD: will the weight loss last? Will it harm me? 

Whilst the VLCD does cause short term weight loss, the long term effects are generally less impressive as weight bounces back after introducing regular food again. Oprah herself regained all the weight she lost in the next two years! The same occurs with the diet’s effects on diabetes with only a third of people in one study being in remission one year after the diet compared to 79% straight after (7). For this reason, it is important to have a long term dietary plan in place to maintain the improvements in weight and glucose levels. 

Because of how extreme the diet is, it is very tough to follow. Side effects from the diet are listed extensively on the NHS website and include: 

– tiredness

– Headaches

– Constipation/diarrhoea 

– And of course – hunger! 

These are most likely to be experienced in the first few days of the diet as your body is experiencing such a difference in caloric intake (1). 

There is also evidence for increased risk of gallstones and other health problems developing (5, 9). 

The Very Low Calorie Diet should therefore only be undertaken after you have talked to your doctor about it, as they will most likely want to monitor you during it especially if you have any other pre-existing conditions (3, 10).

Also it is key that you are getting all your vitamins and minerals that you usually get through a balanced diet – without advice from a health professional you could significantly harm your health if you focus just on calories and neglect the micronutrients that are key to your health as explained by our founder, Catherine Rogers in her book ‘Gut Well Soon’! (5, 13)

RYH provides 4 weeks’ worth of delicious personalised recipes that consider your health conditions including ones especially focused on obesity (12) and diabetes. 

These are a great way to maintain the effects of the VLCD after it finishes and continue your weight loss journey. 

On the other hand, if you want the beneficial effects of the VLCD without being so extreme then consider the weight loss program in RYH – where you can control your calories with daily healthy (and tasty!) recipes. Your gut helps to digest all of your food and so it is surprisingly important to weight loss – a healthy gut can therefore lead to a healthy whole!






5. Tsai, AG., Wadden, TA. (2012) The evolution of Very-Low Calorie Diets: an update and meta-analysis. Obesity. 14(8)

6. Ein, N., Armstrong, B., Vickers, K. (2018) The effect of a very low calorie diet on subjective depressive symptoms and anxiety: meta-analysis and systematic review. International Journal of Obesity. Https:// 

7. Umphonsathien, M., Prutanopojai, P., Aiam-O-Ran, J., Thararoop, T., Karin, A., Kanjanapha, C., Jiamjarasrangsi, W., Khovidhunkit, W. (2019) immediate and long-term effects of a very-low calorie diet on diabetes remission and glycemic control in obese Thai patients with type 2 diabetes mellitus.  Food Science and Nutrition. 7. Pp1113-1122 doi:10.1002/fsn3.956

8. Steven, S., Taylor, R. (2015) Restoring normoglycaemia by use of a very low calorie diet in long- and short-duration Type 2 diabetes. Diabetic Medicine. 32(9) doi:10.1111/dme.12722

9. Johansson, K., Sundstrom, J., Marcus, C., Hemmingsson, E., Neovius, M. (2014) Risk of symptomatic gallstones and cholecytstectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study. International Journal of Obesity. 38 doi:10.1038/ijo.2013.83

10. NICE (2014) Clinical Guidelines No. 189. National Clinical Guideline Centre (UK). London. 

11. [accessed: 26.6.19]


13. Rogers, C. (2019) Gut Well Soon. Panoma Press Ltd. (buy it on Amazon