The evidence about a diet which is low in carbohydrates and high in fat (LCHF) continues to pile up. The latest report is a study from a team based at the Virta Health Clinic in San Francisco (1). A total of 262 people with type 2 Diabetes (T2D) were recruited. The mean age was 54 years and 66.8% (175/262) were female.
The participants were supported by healthcare professionals who had all been trained in the basic principles of achieving and maintaining nutritional ketosis (“fat burning”/capability of utilising fat). They could choose to have access to the educational programme by means of 90-minute group-based classes or by access through the internet. There was an opportunity to understand the background to diabetes and how it can be overcome by switching to a diet, which has a restricted intake of carbohydrates, moderate protein content and relatively high amounts of healthy fats.
Very low carbohydrate intake
In particular, the participants were encouraged to consume <30g per day of carbohydrates, 1.5gm/kg body weight. Fats should eaten to reach satiety. No modifications to participants’ physical activity were encouraged in the first 10 weeks of the intervention.
After 11 weeks, there were some drop-outs but just over 90% remained.
Glycated haemoglobin (HbA1c) is a measure of the average blood glucose (BG) levels over a period of 3 months. At the start of the study the average value was 7.5% and this was reduced to 6.5% after 10 weeks. However the 96 participants with the higher values (> 7.5%) showed a much greater fall (from 9.0 to 7.2%). Clearly this is a very positive result. The success was further demonstrated by the reduction in the need for medication.
The fasting BG values fell from 9.1 to 7.2 mmol/L and the blood triglycerides (TG) also showed a reduction from 2.1 to 1.7 mmol/L.
An average loss of 9 kg in body weight was recorded for all those who completed the study.
Table 1. The relationship between the reduction in HbA1c and the change in requirement for medication
|Change in medication||N||HbA1c, 47.5 mmol/L at follow-up, N (%)||Baseline HbA1c, mmol/L||Follow-up HbA1c, mmol/L|
|No change||88||57 (65)||35.2||47.5|
|All medication stopped||21||17 (81)||49.7||43.2|
|No medication||28||22 (79)||56.3||45.4|
Although a small number were required to increase medication, these results are generally very positive. A total of 133 reduced their medication or were able to stop it altogether. Well over 50% achieved an HbA1c of <47.5 mmol/L, which is regarded as “normal”. With respect to insulin, 28 were able to stop completely and 40 were able to reduce the dose.
Low carb usually works
The totality of the results of this initiative is extremely encouraging. The time scale is relatively short, the degree of support is not excessive but nevertheless the indicators are all moving in the right direction. Undoubtedly the extent of compliance has varied between individuals. So it is almost certain that with many participants, there is considerable scope for further improvement. To anyone who is familiar with developments in this area, there is nothing unusual or surprising about these results. In fact, they are in complete agreement with other work such as that of Dr. David Unwin in his General Practice at Southport in North West England (2). A total of 36 women and 33 men (average age 58 years) agreed to participate. In order to adjust to a low carbohydrate (LC) diet they were advised to reduce sugar and foods with a high starch content such as bread, pasta and rice. This could be replaced by increasing consumption of green vegetables, whole-fruits, such as blueberries, strawberries, raspberries and the “healthy fats” found in olive oil, butter, eggs, nuts and full-fat plain yoghurt were advocated. There was no need to do any calorie counting. Progress was reviewed every month with a GP or practice nurse. All but 2 of the participants completed at least 3 months. The average follow-up period was 13 months so compliance was excellent.
On top of all this there are numerous individuals who have done their own research and decided to switch to a diet that is LCHF. Invariably they find that within a very short period, they become aware of improvements in their personal health, which includes a reduction in body weight.
Official advice is obviously wrong
The big problem is that the changes that obviously are beneficial are in direct conflict with the advice from official sources and the mainstream medical and healthcare professionals. A recent publication from Public Health England (PHE) entitled:
“Healthier and More Sustainable Catering: Nutrition principles. The scientific principles for developing nutrient-based standards for planning nutritionally balanced menus.”
This continues to re-iterate that we should:
“base meals on potatoes, bread, rice, pasta or other starchy carbohydrates; choosing wholegrain versions where possible.”
Other advice is to cut down on saturated fats (SFAs). However there should be some increase in the intake of the polyunsaturated fats (PUFAs). Unfortunately the message that fats are “bad” has become widely accepted and many people have been convinced that it is the SFAs, which eventually “clog up” the arteries.
Healthy fats are required
This is proving to be a stumbling block in persuading people that it makes good sense to consume an LCHF diet. It is certainly true there is growing recognition that sugar is undesirable. However a big difficulty is that many those foods promoted as “healthy” such as rice, bread, potatoes and bread have a high content of starch, which of course breaks down into glucose and therefore contribute to the build-up of glucose in the blood. In other words, the impact on the body is very similar to that of sugar. It really does not make good sense to “base our meals on carbohydrates”. Even if they release the glucose slowly, the fact remains that they contribute to the glucose load in the body and increase the demand for insulin to be produced by the pancreas.
However the greatest difficulty of all is that if the carbohydrate intake is to be REDUCED it has to be replaced by something else. Excessive protein intake is not acceptable and so the obvious answer is to increase the intake of healthy fats. Unfortunately because many have been convinced that fat, especially the SFA, is “bad news” this is not an easy message to get through.
One of the significant aspects of this initiative is that it is a commercial venture. Those who participated were required to pay for the advice/support they received. Clearly they had to be convinced that the service provided was a justifiable expense. The ultimate success is dependent on how the participants perceive the experience and the benefits derived. All the indications are that this has been extremely positive and so it is reasonable to expect that businesses of this type will thrive, which has to be good news all round.