This is one reason why people struggle so much with dieting. They lose lot's of weight at first, but then plateau when the body adapts. When they get discouraged and fall off the diet, they put the weight back on quickly because they now are burning less calories than when they started.
The most effective way of losing weight long term is likely some combination of a slight caloric deficit paired with resistance training (to discourage the body from shedding metabolically expensive tissue) and short bouts of reverse dieting . (ie. slight deficit for 3 weeks, then 1 week of a slight surplus, etc.)
Edit: When I said that the body is unaffected by it, I was referring to the fact that fibre does no trigger the same cascading chemical reaction that other carbs do. No amount of fibre will cause an insulin spike and increased fat storage.
The types of foods (and NNSs) we consume, and the chemical affects they have, are more important than the amount we consume.
Energy value of dietary fibre
A value of 2 Cal (8 kJ) per gram should be used for the dietary fibre portion of the fibre source.
A value of less than 2 Cal (8 kJ) per gram may be used for the dietary fibre content if a specific value is available for the fibre source.
Energy value of bran
The energy value of the fibre portion of wheat bran is 0.6 Cal (2.5 kJ) / g and the wheat bran itself has an energy value of 2.4 Cal (10 kJ) / g.
The commenter above is talking about how we often ignore the adaptability of the body, and that if you suddenly cut caloric intake by say 300 a day, the body will surprisingly quickly adapt by lowering metabolic rate to compensate. This can be done through the simple modulation of hormones and may also involve the shedding of metabolically expensive tissue, like muscle.
I.e., as with many metareports, it's kinda worthless, it seems.