Can high-fat diets fight diabetes – and lower the cost of diabetes treatment?

We're all familiar now with the idea of "good fats" and "bad fats", with fish oils in the role of "good" and saturated animal fats the "bad”.

The progress of nutrition science is now taking this idea a step further. It's not only challenging the scientific basis of the idea that "low-fat diets are best" but providing evidence for the idea (a heresy to health professionals) that fat is, in fact, good for you.

People with Type 2 diabetes are usually advised to follow a low-fat diet. But a study by Linköping University in Sweden – a respected research centre - found that food with a lot of fat and few carbohydrates can in fact have a better effect on blood sugar levels and blood lipids.

The results of a two-year dietary study led by Hans Guldbrand, general practitioner, and Fredrik Nyström, professor of Internal Medicine, are published in the prestigious journal Diabetologia.

61 patients were included in the study, randomized into two groups, and they followed either:

• a low-carbohydrate/high fat diet (50% of the energy from fat, 20% from carbohydrates and 30% from protein)
• or a low-fat diet (30% from fat, 55-60% from carbohydrates, 10-15% from protein, which corresponds to the diet recommended by the Swedish National Food Agency).

In both groups, the participants lost approximately 4 kg on average. In addition, a clear improvement in the glycemic control was seen in the low-carbohydrate group after six months. Their average blood sugar level dropped from 58.5 to 53.7 mmol/mol (the unit for average blood glucose). This means that the intensity of the treatment for diabetes could also be reduced, and the amounts of insulin were lowered by 30%.

Despite the increased fat intake with a larger portion of saturated fatty acids, their lipoproteins did not get worse. On the contrary – the HDL, or 'good' cholesterol, content increased on the high fat diet. High levels of HDL are a protector against heart attacks.

No statistically certain improvements, either of the glycemic controls or the lipoproteins, were seen in the low-fat group, despite the weight loss.

"You could ask yourself if it really is good to recommend a low-fat diet to patients with diabetes, if despite their weight loss they get neither better lipoproteins nor blood glucose levels," Nyström says.

For most dietitians and medical practitioners the "low-fat diet is best" hypothesis is a form of a religious belief and studies such as this are scorned by them as heresy.

But with over 300 million people in the world with diabetes (according to the WHO) and insulin treatment costing €1,000 ($1,300) per person per year at a time when health budgets are under increasing strain, any advances in dietary knowledge that can cut that cost by 30% are welcome.

Beliefs should not be allowed to outweigh growing scientific evidence. Major bodies of research have already busted the myth that there's any connection between dairy fat and cardiovascular disease (on the contrary, dairy seems to make you healthier). Studies such as this are just the tip of the iceberg of change that's coming. But you can be sure that health professionals - an intellectually rigid bunch on the whole - will be the last to adapt.