INTRODUCTION
Imperfect dieting is a major cause of the progression (i.e. inevitably getting worse) of diabetes. Due to insufficient understanding of diabetes (reasons and improvements for this are given below), patients when diagnosed do not receive all the information necessary to reliably control their diabetes by healthy diet and exercise alone. (From now on "diet alone" includes exercise). This shortcoming accelerates progression of their diabetes into both medication – e.g. one tablet, tablets, then insulin for the rest of their life, with a variety of possible side-effects – and also grisly complications. These diabetic complications are mainly: coronary heart disease (from which about 80% of diabetics die prematurely in developed countries), stroke, blindness, kidney failure, lower leg amputation, impotence, and widespread nerve damage. Accelerated mental decline (to dementia and Alzheimer's disease) and depression also occur with poorly controlled diabetes. Ask any diabetic, with any of these complications, if you doubt the importance of taking preventative action while you can to stay free from them.

The DiabeticOptiCarbDiet (from now on DOCD) is probably the first comprehensive lifestyle change package that can reliably delay both complications and blood glucose (from now on BG) control medication over the long-term (i.e. 11 years, and still counting). So DOCD is intended for Type 2 diabetics and pre-diabetics trying to control their BG by healthy diet alone. This ability to delay diabetic complications, ideally up to the end of the diabetic's natural lifespan or until a cure for Type 2 is available (if sooner), is the most important requirement from any diabetic diet. Next most important are usually the lifestyle change not taking over one's life (after the initial effort, DOCD becomes second nature), and also the ability to eat enjoyably and healthily (even while losing weight) – which DOCD also provides.

DOCD was created by a Type 2 diabetic (Dr Roger Grant – a scientific PhD, with a GP doctor wife; more background in footnote below), initially just for his own self-preservation and eating pleasure. Roger, while aware of both the uncertain effects of medicinal chemicals on the human body and also of their benefits, preferred to control his diabetes by healthy dieting alone for as long as possible. He is now in his 12th year of freedom from both complications and BG medication, and eating enjoyably. This in spite of DOCD indicating that his pancreas produces little natural insulin, due to significant beta-cell exhaustion. DOCD has kept his 6-monthly DCCT-aligned HbA1c* test values in the narrow range 6.2-7.3% (44-56 mmol/mmol in the new units) since early 2001 (when the test method was revised), after an equivalent value at diagnosis of 8.6% (70 mmol/mmol) in 1998. The latest four values ranged 6.2-6.4%. These figures compare with the general advice to stay below 7.0%, or better still below 6.6%, in order to reduce the likelihood of complications. After the initial highly detailed 5-year case study of himself, Roger piloted the findings among other diabetics for 3 years to provide wider perspective on their applicability. He then rewrote DOCD, so as to make it simpler to follow and less time-consuming for healthcare professionals, but without reducing its effectiveness.

* HbA1c (also called A1C) is the average percentage of glucose attached to the blood's hemoglobin, and also a measure of average BG level itself – each averaged over the previous 3 months.

HOW DOCD OVERCOMES THE SHORTCOMINGS OF EXISTING DIET ALONE ADVICE
Early in the research, Roger recognized some major shortcomings in existing advice on control by diet alone. It is a common sense principle of control theory, that to control something adequately it has to be measured suitably. The four main shortcomings, together with DOCD’s improvements, are now described. Without these improvements, existing advice is less than half the solution to lasting control.

1. Insufficiently precise ways of finding the ‘safe’ (i.e. optimum) weight of each healthy carbohydrate-containing food for each snack or meal. This in spite of the amount of carbohydrate (from now on carb) eaten being widely acknowledged as the strongest single influence on postprandial (i.e. after eating) BG increase. Each time a person eats carb, insulin (from their pancreas) helps the resulting BG to enter their muscles' cells and other body cells – thus resulting in a postprandial BG peak. (See diagram below). In non-diabetics, these BG peaks can go up to about 10.0 mmol/L** (180 mg/dL in US units). In diabetics, the high BG damage leading to complications is seen as resulting during time spent above this 10.0 mmol/L level. So DOCD is aimed at keeping BG level below the levels at which the artery damage causing complications occurs – by limiting the postprandial BG peak from going above 9.0 mmol/L (162 mg/dL) normally, and very seldom going above 10.0 mmol/L. By way of perspective, when Type 2 diabetes is diagnosed, macrovascular (i.e. large artery) damage, which leads to coronary heart disease and stroke, has usually been present for some years. If BG values are allowed to spend time above 10.0 mmol/L, microvascular (i.e. small artery) damage follows, and this leads to the other complications listed in the first paragraph. These high BG levels also aggravate existing macrovascular damage.
   

   ** All BG values are for glucose meters reporting their results as capillary whole blood – as distinct from those tuned to report as venous blood plasma, which give approximately 12% higher values. Look in your meter's manual to see which it does.
   

   Official past guidelines for determining 'suitable' food weights for snacks and meals have been: Exchanges, Carb Counting, the Food Pyramid, MyPyramid, and 40-60% of daily energy (i.e. calorie) intake being (mainly starchy) carb. (40% is a Joslin Center value). None were sufficiently accurate for proper diet alone control. When the DOCD research began, there was institutional advice to keep postprandial BG peak below 10.0 mmol/L (180 mg/dL) two hours after starting to eat. See how this criterion works for the diagram. It shows the postprandial curves for a Type 2 diabetic and a non-diabetic eating 70 dry grams of cooked porridge oats (plus skimmed milk; no sugar or cinnamon, but the latter is usually eaten with it) under the same conditions with the preprandial starting point being moved to 6.0 mmol/L in both cases. (The non-diabetic’s was actually 5.0 mmol/L). The diabetic’s BG comfortably met the above advice to be below 10.0 mmol/L two hours after starting. Yet it peaked at 12.2 mmol/L (220 mg/dL) and spent 65 min above 10.0 mmol/L. In late 2008, the UK’s official recommendation was changed to keeping below 8.5 mmol/L two hours after eating, but that would not have improved this situation significantly. Evidently these criteria did not serve their intended purpose. The shape of each BG/time curve can vary widely according to the individual eater, the foods present and their amount, and the food previously eaten – thus undermining the use of such spot criteria. They will work better for some medications, but not for diet alone control where typically there is little, or no, first release of pancreatic insulin upon eating and a weak second release somewhat later. Their normal influence is shown by the non-diabetic's curve. This is an example of an official recommendation, that applies to medication, being inappropriately applied to diet alone control over many years without correction.
   

   DOCD follows the official 40-60% carb advice mentioned above, but not the “(mainly starchy) carb” aspect. This latter advice has led to the creation of alternative diets – due to starchy foods having a high Glycemic Index (from now on GI) that pushes up BG levels. Among these are low-carb diets, which approach the difficulty of predicting postprandial peak levels by intentionally selecting very low carb weights – much lower than DOCD’s, which is not low-carb. However in low-carb diets, more calories have to come from fats and proteins. The unknown long-term health effects of this, together with less and fewer of the micronutrients gained from eating more carb, involve taking an unnecessary risk – whereas DOCD meets recommended nutritional balance. DOCD from its beginnings, has included some aspects of other diets, such as the healthy food in the Mediterranean Diet and the ‘gentle’ foods of the Low GI Diet. However DOCD followers can also eat healthy ‘non-Mediterranean’ foods, and medium and high GI foods, and treats – but not above their optimum amount. DOCD involves eating conventionally healthy foods – nothing 'weird'.
   

   To chacterize postprandial peak values, the DOCD research included over 100 variously structured eating experiments, using finger BG testing at 10 min intervals (as in the diagram above). The main finding from analyzing this data was a method for determining the maximum (i.e. ‘safe’) weight of any carb-containing food(s) a diabetic could eat without their postprandial BG peak going above 9.0 mmol/L (162 mg/dL) normally, and very seldom above 10.0 mmol/L (180 mg/dL). Lower upper limits are possible for some people. Piloting the findings among other diabetics showed that each diabetic had their own grouping of such food weights, according to their diabetic severity, etc. This usefully put numbers on the widely held general beliefs that: “Everyone is different” and "One size does not fit all". An easy short-cut was developed to enable DOCD users to determine their personal such weights – and so by-pass the huge amount of testing involved in the research. Please note that although these food weights are the maximum food weights that can be eaten ‘safely’ (i.e. optimum carb, thus The DiabeticOptiCarbDiet) from a BG peak viewpoint, smaller quantities can be eaten if desired.
   

2. Too much noise. The word “noise” given to radio interference, is also used for unwanted irregular influences that interfere with drawing conclusions from experiments. (You have probably encountered them in your own BG testing). Commonly, a vicious circle (cycle) is prevailing when a person first starts following DOCD. As the pancreas is treated more kindly, by lowering postprandial peaks and other DOCD measures, so the vicious circle gradually changes into a virtuous circle, which is more predictable. (There are good biochemical explanations for this slow change). Reducing the "noise" thus, allowed further refinements to be discovered. This does not mean that your diabetes has been cured. It can revert back towards the vicious circle, for example on holiday, due to greater eating and drinking and the different choice of food, but DOCD has approaches for returning to the virtuous circle. Similarly, celebratory meals and ‘treats’ can be returned to virtuous conditions, providing they are not too frequent.
   

3. No ‘real time’ feedback. In many industrial manufacturing processes, there are instruments providing continuous measurements of important finished-product properties. For example, measuring the thickness of a continuous plastic film, so that the finished-product is not too thick and therefore wastefully costly in raw material, and not too thin and therefore too weak. This is called “real time” feedback, because the information is fed back upstream sufficiently quickly for the process (e.g. raw material addition rate) to be corrected beneficially. Compare this with making a change to your dieting, and then having to wait up to 3 to 6 months for the result of your next HbA1c (A1C) and other examination results. Even then, since HbA1c is an average of BG values over the previous 3 months, it can tell you nothing about how you dieted for any particular snack or meal. By contrast, because DOCD eliminates most of the “noise” that upsets the interpretation of readings (Item 2 above), it does provide a simple method of real time feedback that enables one’s dieting techniques to be continuously improved.
   

4. Meaningless BG testing. There is an on-going debate in the UK National Health Service (from now on NHS) as to whether those controlling by diet alone should be given any test strips (or equivalent) for finger testing, because using them has generally not shown BG control improvements.*** The likely explanation, for this lack of success, is patients having been told either to keep below 10.0 or 8.5 mmol/L after 2 hr (as harmfully adhered to in the diagram above), or to do other testing that is not meaningful. By contrast, DOCD’s use of peak postprandial values to determine the maximum weight of foods that can be eaten without BG going up to dangerous levels, effectively does away with postprandial testing. DOCD also looks after preprandial levels, so that once the diabetic has settled down inside DOCD (the time depends mainly on how hard they work at it), finger test monitoring can be reduced to once per week. Occasional ‘spot’ tests and experimentation are additional. That way DOCD patients achieve effective control, and the NHS economizes on strips.
   

   *** In March 2010, an NHS Diabetes Working Group released a report designed to clarify and improve the matter. [Heller, S. et al. Self monitoring of blood glucose in non-insulin-treated Type 2 diabetes. http://www.diabetes.nhs.uk/publications_and_resources/reports_and_guidance/]. While not always distinguishing between diet alone and non-insulin BG medication (where lasting control is more difficult), the report essentially endorsed some shortcomings long flagged by DOCD. Namely, an absence of effective BG test control approaches; the resulting ignorance of both healthcare professionals and patients in interpreting BG test results; and the remote relevance of an HbA1c value to day-to-day eating. In addition, some patients' inability to get meaning from their BG readings contributed to psychological anxiety and depression. The report's "systematic" analysis of published past trials of self-monitoring BG – found a reduction in HbA1c of only 0.52% where education and/or feedback were included, and just 0.25% where they were not included. (Compare these with the considerably higher DOCD HbA1c reductions given above and below). Among the report's conclusions, the "few individuals" who got benefits from self-monitoring BG (sometimes just the general effects of eating, exercise, etc) should be given strips to continue testing. The funds for others' strips should be redirected to educating staff and these other patients. Also that future research be focussed "on how to identify those who will gain most from self-monitoring BG and establish how they integrate it successfully into their approach to self-management." .... "There is no place for a one size fits all approach". (DOCD provides each individual's 'size'). This report is one of several recent publications, showing the low current 'official' level of understanding, which illustrate that DOCD is well ahead in the field of diet alone control. Some of DOCD's aspects are probably relevant to improving non-insulin medicated Type 2 BG control.