I don't think there's any magic in it (Stillmans). I've just finished a particularly strict Stillmans day - here is the breakdown from Fitday:

Calories Eaten Today
source grams cals %total
Total: 933
Fat: 48 436 51%
Sat: 8 69 8%
Poly: 4 33 4%
Mono: 8 70 8%
Carbs: 9 36 4%
Fiber: 0 0 0%
Protein: 96 382 45%
Alcohol: 0 0 0%

As you can see over 50% of the calories still come from fat - despite the fact that I didn't overtly eat any. All meats and eggs contain fats. I don't think it is low fat therefore. It could be low carb. - 9 carbs is way below what I'd get on Atkins. But look at the calories - only 933. I should be eating about 1,700 a day.
My opinion is that it's a low calorie diet - but one that is helped along by the fact that it is also low carb and the protein has a very strong hunger surpressing effect.

Tomorrow is back on Atkins for me - my chosen plan. I will be up to 70% fat, 1,700 calories and 20g approx of carbs. I can hardly wait to sink my teeth into a lump of cheddar.

Stillmans may be useful as a stall buster but it is hardly healthy eating! It is 0 fiber and one thing I didn't mantion in the earlier post is that it gave me quite bad diarrhea!

Also, although several long termers have tried stillamans as a way of getting back to basics I don't know anyone who's stuck it out for longer than 6 days.

If you're losing on your normal plan, leave Stillmans alone. I was stuck for a year before I tried it and Atkins is still my way of eating for life.