After six months, the non-diet group had lost an average of 1% of their weight, the calorie restriction group, 10.4%, those who were on a calorie restricted diet plus exercise, 10% and the very low-calorie diet, 13.9%.

BBC: NEWS | Health | Low-cal diet 'long-life benefits'

But the benefits of calorie restriction require that mice live on a restricted diet for most of their lives.

FORBES: Magazine Article