A Paleolithic-type diet is based on lean meat, fish, eggs, vegetables, fruits, nuts and berries, with rapeseed, olive oils and avocado as additional fat sources. The diet excludes dairy products, cereals, added salt and refined fats and sugar.
"Eating a Paleolithic-type diet without calorie restriction significantly improved the fatty acid profile associated with insulin sensitivity, and it reduced abdominal adiposity and body weight in obese postmenopausal women," said Caroline Blomquist from Umea University in Sweden.
Researchers conducted their 24-month intervention in 70 obese postmenopausal women with normal fasting plasma glucose levels. The women were randomly assigned to one of two groups.
Those in the Paleolithic-type-diet group aimed to consume 30 per cent of their total energy (energy per cent or E per cent) in protein, 30 E per cent in carbohydrates, and 40 E per cent in fats with high unsaturated fatty acid content.
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By contrast, the women in the prudent control diet group aimed to eat 15 E per cent in protein, 30 E per cent in fat, and 55 E per cent in carbohydrates, researchers said.
Body measurements and proportions, food intake and physical activity, as well as circulating lipid levels, gene expression in fat of key factors in fat metabolism and inflammation, insulin resistance and relative fatty acid composition in plasma, were documented at baseline and at 6 and 24 months.
At 24 months, the women eating the Paleolithic-type diet reported that their intake of saturated fatty acids decreased by 19 per cent; of monounsaturated fatty acids increased by 47 per cent; and of polyunsaturated fatty acids increased by 71 per cent, researchers said.
Specific fatty acids associated with insulin resistance were significantly lower in the women eating the Paleolithic-type foods compared with those on the prudent control diet, they said.
At 24 months, the women on both diets lost significant body weight and had significantly less abdominal obesity.
"Obesity-related disorders have reached pandemic proportions with significant economic burden on a global scale. It is of vital interest to find effective methods to improve metabolic balance," said Blomquist.