Contents:

• Executive summary
• What is diabetes?
• Type 1 diabetes
• Type 2 diabetes
• Gestational diabetes
• Metabolic syndrome
• Pre-diabetes
• Common health complications
• Why do people become diabetic?
• Genetics
• Lifestyle and environmental factors
• Life with diabetes
• Classical approach to treatment
• Medication
• Type 1 diabetes
• Type 2 diabetes
• Diet
• How well does it work?
• The D-Diet
• Basic principles of the D-Diet
• Why and how it works
• The D-Diet nutrition basics
• Conclusion
• References

Basic principles of the D-Diet

Summary

In summary, the D-Diet should contain only foods from plant sources, a minimum of oils and should be rich in foods with a low glycemic index. For these reasons, the D-Diet is based on whole grains, pulses, vegetables, fruit and nuts and seeds (see the D-Diet nutrition basics, page 22, for more information on plant-based nutrition). Whilst limiting the types of food eaten, this diet does not limit the amount of food consumed. Being high in fibre and digested gradually, the recommended foods make the consumer feel full sooner and for longer, while calorie intake is reduced by the minimal amount of fat it contains (per volume of food eaten).

In this section, the basic principles of a diet used for preventing, treating and reversing diabetes are described together with explanations of each of them. The next section (‘Why and how it works’ on page 20) then provides a more detailed insight into how this diet influences the body’s processes. Anyone switching to the D-Diet should remain in close touch with their doctor as glucose control and insulin sensitivity can improve relatively quickly and there might be need for medication adjustment – a decision that needs to be made by a doctor, never by the patient.

1st principle: no to animal products

By eliminating all animal products (meat, fish, dairy, eggs) diabetics avoid eating substantial amounts of fat and their cholesterol intake will be zero. Even lean, white meat and fish contain surprisingly high amounts of fat. For example, 38 per cent of calories from roast chicken and 40 per cent of calories from salmon come from fat (Food Standards Agency, 2002).

Although promoted as a source of omega-3 fats, fish oils also contain cholesterol and a significant proportion of their fat is saturated fat – between 15 and 30 per cent, depending upon the species (Barnard, 2007). Dairy products, even low-fat varieties, inevitably contain fat and most of it is saturated fat. There is no requirement for saturated fats in our diet.

Reducing fat intake is vital for many reasons – in order to reduce the amount of intramyocellular lipid (which interferes with muscle cells’ insulin sensitivity), for cardiovascular health and for general weight loss.

This diet excludes all animal products also because animal protein from meat, fish, dairy or eggs places an additional strain on the kidneys and can damage them (Knight et al., 2003; Barclay et al., 2010). Plant proteins do not appear to cause the same problem (see pages 16 and 21). Protecting the kidneys is another key issue on the way to better health.

All foods should be of plant origin and unrefined wherever possible, which means they will be naturally high in fibre and complex carbohydrates, and low in fat (except oils, nuts and seeds). Animal products contain no fibre or healthy carbohydrates while plant foods contain all the essential nutrients we need.

It has been found that avoiding certain foods entirely is easier than attempting to moderate their intake (Trapp et al., 2010). Reducing the intake of problem foods may not have the desired effect and cravings for them may never be lost. Avoiding them entirely, on the other hand, enables the taste to adjust to the new way of eating and problem foods are likely to lose
their appeal.

2nd principle: low-fat

Even though vegetable oils are better for the body than animal fats because they contain essential fatty acids, less saturated fat and no cholesterol, it is important to keep them to a minimum. In order to reverse or improve the diabetic condition, it is essential to eliminate intracellular fats (Barnard, 2007) but this can only happen if excessive fat consumption is avoided. By eating low-fat foods, the body is still likely to obtain the essential amount of fat
it needs, but not more.

One of the pilot studies on the effects of a vegan diet showed that there are important differences between types of fat in a low-fat regime (Nicholson et al., 1999). Researchers compared the potential of a lowfat vegan diet with a conventional low-fat diet. Participants were all type 2 diabetics and they followed the assigned diet for 12 weeks. At the end of
the study period, the vegan group had 28 per cent reduction in fasting plasma glucose levels (tests carried out after approximately 12 hours without eating). The reduction in the conventional group was significantly lower – only 12 per cent. The average weight loss was 7.2kg in the vegan group compared to 3.8kg in the conventional group. Medication was
reduced in all vegan participants, in one of them completely, whilst there were no reductions in medication in the conventional group.

When individuals with impaired glucose tolerance were tested repeatedly for diabetes and their eating habits were examined (Marshall, et al., 1994), it was found that excessive fat consumption significantly increased the risk of developing diabetes. A recent review of studies on bariatric surgery (a surgical procedure reducing the size of the stomach and gut available for nutrient absorption, performed on severely obese people) (Andreelli et al., 2009) revealed a startling result. Type 2 diabetes can be reversed within days of the surgery, even before any
significant weight loss is achieved. The main mechanism for this dramatic change is the sudden decrease of triglycerides and free fatty acids in the blood and rapid reduction of fats in liver and muscle cells. Such drastic changes are obviously not achievable immediately through diet but the effects of this surgery clearly illustrate the efficacy and importance of a low-fat diet.

The amount of fat per serving should not exceed three grams (or ten per cent of calories from fat). Apart from added oils, diabetics should also limit their consumption of nuts and seeds.

3rd principle: low glycemic index (GI)

Glycemic index, or GI, is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and rapidly release glucose into the blood have a high GI. Carbohydrates that break down more slowly, releasing glucose gradually into the bloodstream, have a low GI.

To help the body deal effectively with the carbohydrate content of different foods, those that release their energy slowly should be preferred. Low GI means that after ingestion, blood glucose will not reach high levels, which is exactly what people with diabetes need. It allows them to better control their blood sugar and reduces the likelihood of complications caused by hyperglycaemia, such as retinopathy, neuropathy and nephropathy (kidney disease).

Glycemic index of selected foods (from Glycemic Index Database and The GI Diet Guide)

Results from 14 studies on glycemic index show that choosing low GI foods alone reduces HbA1c (for both types of diabetes) by 0.3 to 0.4 percentage points. In some of the studies, the difference was even higher – 0.6 points (Brand-Miller, 2003). The authors concluded that the benefit of low GI food consumption is similar to that offered by medication targeting  postprandial (after eating) hyperglycaemia. Another review (Willett et al., 2002) came to a similar conclusion and the authors suggested that low GI foods improve glycemic control and reduce hypoglycaemic episodes in people treated with insulin.