I drink green tea almost religiously (I like the taste--and its a lot healthier than drinking pops) -- but sake I only take in cocktail form... I highly doubt that's gonna help weight loss.
But I've never heard of sake for weight-loss or conventional health benefits (I do believe it is used in Eastern medicine, though unlikely for weight loss)
Current program: 1,800 calories most days of the week; 45-60 minutes of mixed exercises (weights, cardio-kickbox, dance, athletic intervals) 6 days a week
Current goal: 135 pounds by birthday (July 14th) and to run half marathon at end of May.