Foods of the kind that were consumed during human evolution may be the best choice to control diabetes type 2. A study from Lund University, Sweden, found markedly improved capacity to handle carbohydrate after eating such foods for three months.

During 2.5 million years of human evolution, before the advent of agriculture, our ancestors were consuming fruit, vegetables, nuts, lean meat and fish. In contrast, cereals, dairy products, refined fat and sugar, which now provide most of the calories for modern humans, have been staple foods for a relatively short time.

Staffan Lindeberg at the Department of Medicine, Lund University, has been studying health effects of the original human diet for many years. In earlier studies his research team have noted a remarkable absence of cardiovascular disease and diabetes among the traditional population of Kitava, Trobriand Islands, Papua New Guinea, where modern agrarian-based food is unavailable.

In a clinical study in Sweden, the research group has now compared 14 patients who were advised to consume an ‘ancient’ (Paleolithic, ‘Old stone Age’) diet for three months with 15 patients who were recommended to follow a Mediterranean-like prudent diet with whole-grain cereals, low-fat dairy products, fruit, vegetables and refined fats generally considered healthy. All patients had increased blood sugar after carbohydrate intake (glucose intolerance), and most of them had overt diabetes type 2. In addition, all had been diagnosed with coronary heart disease. Patients in the Paleolithic group were recommended to eat lean meat, fish, fruit, vegetables, root vegetables and nuts, and to avoid grains, dairy foods and salt.

The main result was that the blood sugar rise in response to carbohydrate intake was markedly lower after 12 weeks in the Paleolithic group (–26%), while it barely changed in the Mediterranean group (–7%). At the end of the study, all patients in the Paleolithic group had normal blood glucose.

The improved glucose tolerance in the Paleolithic group was unrelated to changes in weight or waist circumference, although waist decreased slightly more in that group. Hence, the research group concludes that something more than caloric intake and weight loss was responsible for the improved handling of dietary carbohydrate. The main difference between the groups was a much lower intake of grains and dairy products and a higher fruit intake in the Paleolithic group. Substances in grains and dairy products have been shown to interfere with the metabolism of carbohydrates and fat in various studies.

"If you want to prevent or treat diabetes type 2, it may be more efficient to avoid some of our modern foods than to count calories or carbohydrate," says Staffan Lindeberg.

This is the first controlled study of a Paleolithic diet in humans.