However, most measurements of mood revealed a lasting improvement in only those following the low-fat diet, while those on the high-fat diet returned to their initial levels (mood turned towards more negative baseline levels).

'The obesity epidemic has led to widespread interest in alternative dietary patterns for weight management,' the authors write.

'While recent clinical studies have shown that low-carbohydrate diets can be an effective alternative dietary approach for weight loss, their long-term effects on psychological function, including mood and cognition, have been poorly studied.

'This outcome suggests that some aspects of the low-carbohydrate diet may have had detrimental effects on mood that, over the term of one year, negated any positive effects of weight loss,' the authors write, according to a CSIRO release.

These findings were published in the November issue of Archives of Internal Medicine.