The researchers in South Korea used two groups of rats, which were put on a high-fat diet. They found that the group that received 10 per cent of its energy from black soya beans put on half as much weight as the other group, 25 per cent fall in cholesterol levels and as much as 60 per cent drop in the LDL cholesterol, which is considered bad cholesterol.


The researchers, who have published their study in the Journal of the Science of Food and Agriculture, say black soya beans may be more effective in reducing fat and cholesterol levels than yellow soya beans, which are already an established food item helping to reduce weight.

The scientists said it could be the soya protein's effect on fat metabolism, which helps glycaemic control by reducing weight.

The researchers were led by Shin Joung Rho at Hanyang University, Seoul.

Soya is an important crop grown for oil and protein. There are black, brown, blue, yellow and mottled varieties.