We never need much of an excuse to have a cup of tea but we now have yet another reason to justify our five-a-day habit.

Your morning cuppa could help you lose weight, according to a new research. A study has found that black tea stimulates the production of good bacteria in the gut and boosts metabolism. Researchers at the University of California conducted the study using mice. The mice were split into four groups based on diet - low-fat, high-sugar; high-fat, high-sugar; high-fat, high-sugar and green tea extract and high-fat, high-sugar and black tea extract. The researchers tracked the mice's weight over a four-week period and found that those which had had black or green tea extract in their diets lost as much weight as the mice on the low-fat, high sugar diet. The mice's intestines were shown to have less bacteria associated with obesity and more bacteria associated with lean body mass. They also produced more Pseudobutyrivibrio, a type of gut bacteria associated with metabolism. Green tea has previously been linked with metabolism but this study is one of the first to highlight the benefits of black tea. "Our new findings suggest that black tea, through a specific mechanism through the gut microbiome, may also contribute to good health and weight loss in humans," said Susanne Henning, the study’s lead author. “For black tea lovers, there may be a new reason to keep drinking it." Sadly, the researchers only used decaffeinated tea in the study, so we'll just sit here sipping until someone discovers our favourite regular teas have magical powers.