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The benefits of low Calorie diets for diabetics


11 Oct 2011

The media world has been absolutely saturated with articles carrying headlines such as ‘Type 2 diabetes can be cured by extreme diet’. This is important news, and it is imperative that the information be clearly understood.
The patients’ health – and perhaps their lives – depends upon healthcare professionals’ recognition of the value of this information. Unfortunately, the sensationalist language in which the reports have couched the results will unnecessarily discourage many overweight people. Even healthcare providers may ignore the message. Patients will continue to needlessly suffer from the dire consequences of diabetes. It is important to recognise that although the language may be extreme, the diets are not.
First of all, it must be made clear that the results that have received so much publicity recently are not ‘news’. The only unique aspect of this particular study1 is the degree to which it has managed to dominate the media, when more than 30 prior years of scientific and medical publications (involving thousands of diabetic patients) have seen diabetes put into remission within a few days on a VLCD. Not a word of these studies appeared in the public media and only those healthcare professionals who kept up to date with the scientific literature were aware of the findings. Even they, however, were discouraged by the sinister notion of an ‘extreme diet’.

The VLCD
There is nothing ‘extreme’ about the modern VLCD. Before we come back to that, it is also critical to understand that neither the diet used in this report nor a proper VLCD cause the ‘cure of diabetes’ any more than bariatric surgery can cure diabetes. The immediate drop in blood sugar with surgery or VLCDs is due to the sudden unavailability of dietary carbohydrates, which forces the body to utilise the excess sugar it carries in circulation and storage.
The crucial fact is that remission of type 2 diabetes is due to weight loss. Excess weight is well known to be a major contributor to the development of diabetes, and the loss of the excess weight will usually reverse the process. Ultimately, the carbohydrate provided by the diet formula, supplemented by three carbon sugars released from triglycerides as fat becomes mobilised for energy, keeps blood sugar at a normal level and diabetes in remission. What the modern, nutrient complete, VLCD can do very effectively is ensure weight loss at a maximum safe rate, without the need for the risks of bariatric surgery with the inevitable subsequent nutritional problems caused by nutrient malabsorption.
It is something of a paradox that a dietary programme that actually provides an individual with all essential dietary needs should be considered ‘extreme’. Although conventional ‘chatroom wisdom’ might place great importance on the Calorie content of the dietary intake, this concern is actually unwarranted. A car’s tank may hold 40 litres of petrol, but there is no point in filling the tank with this amount if the tank is already full. Overweight individuals have an enormous number of Calories in reserve in their fat stores. In essence, their petrol tank is already full. In evolutionary terms, that is what fat is for: to provide Calories, when required, at a rate of 7,700 Calories for each kilogramme of stored body fat.
The number of dietary Calories needed (Calories entering the body from the outside) is determined by the nutrient content of the food consumed. Without supplements, the nutrient availability in ordinary foods is sufficiently diffuse that it is virtually impossible to construct a nutrient-complete diet that adds up to less than 1,200 Calories daily. With a normal food diet, cutting the Calorie intake below 1,200 Calories creates inevitable nutrient deficiencies and the dieter becomes ill. A modern nutrient complete VLCD is simply an enteral feed with sufficiently low fat that many of the daily Calories have to be drawn from the fat reserves of the body. That is what is commonly known as a ‘diet’.

A tremendous safety record
Very low Calorie diets have been in worldwide use for more than 30 years, with a tremendous safety record. Although they may differ somewhat in their composition (and in the professional competence of those monitoring the programme) they have been repeatedly shown to be very safe. Safety of use is determined entirely by recognition of the concurrent medical conditions at the time of use. For example, the use of a VLCD by a diabetic patient needs the doctor to stop hypoglycaemic medication prior to the patient dieting. If the weight loss reduces blood pressure in a patient using antihypertensive drugs, the patient may become overmedicated. If a person diets while they are being assessed for thyroid hormone supplementation, the blood thyroxin levels will be inaccurate and the dose will be wrong.
These diets really work and therefore care is needed in selection and monitoring of patients. The provision of a proper maintenance programme (not always available from various VLCD purveyors) makes a great difference in the prevention of recidivism. Long tem outcomes are therefore programme specific.
The UK is very fortunate to have in place a network of highly trained, expertly led, pharmacy based VLCD programmes run exclusively by healthcare professionals. This supplements the long standing GP and hospital availability. The availability of continuous audit data from these programmes, documenting the weight loss success of these programmes, even in very obese people, is continuing proof of their value.

The evidence
Don’t let sensationalist language used in media reporting hinder patients benefiting from a valuable mode of treatment. Properly formulated and monitored VLCDs save lives. Appropriate maintenance formulations help reduce recidivism.
There is considerable longstanding scientific literature demonstrating that the rapidity of weight loss confers additional positive health benefits (independent of the actual amount of weight which is lost) when compared with food based diets or higher energy level formula diets. This applies particularly to non insulin dependent diabetes mellitus2,3,4,5,6. In these studies metabolic control and lipid profile is markedly improved by the rapid fall in weight using VLCD. Wider recognition of this and much more literature will hopefully put an end to the use of off-putting language which discourages acceptance of an important medical tool.

S.N. Kreitzman, S.A. Kreitzman and V. Beeson,
of Howard Foundation Research


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