In a study we went over in one of my classes a while back, atkins was shown to cause weight loss simply due to calorie restriction because atkins is usually high fat, and it fills you up faster.
It is unhealthy if you pick the wrong foods, it makes you feel like crap- irritable. and in the end the study showed it caused weight loss, but bodyfat %-age remained about the same.
First I would try to increase the number of meals- just make them smaller (reduce intake and increases metabolism). Exercise! And about every 8 days, throw in one day with normal food intake (still more meals though) to prevent your body from adjusting to lower calorie intake.
BTW- protein shakes, slim fast shakes, any small meal replacements work great as those extra meals since they are typically low calorie, and have a bunch of vitamins
if you still need diet advice- the zone diet was the only healthy "FAD" diet we covered and had good results- there's a book you can buy with ideas on how to implement it- it's worth a look if you're looking for a well rounded healthy diet