Not really enough info the make an educated guess on, but I've seen this sort of thing in others- I've lost a lost of weight, but many friends and family members supposedly tried things similar to what I have done and have gone nowhere.

I suspect a few things- eating too frequently. I settled into eating around twice a day. Basically, I could just eat meat for a few days, eventually the cravings die down, and then it's like a game: am I hungry yet? How long can I go with out food here?

If you think you have to have breakfast- or worse, like my brother, decide to eat small meals 5 or 6 times a day- when does your body have time to burn what you've got around your waist?

Additionally, these foods often do have more calories than the foods we are replacing them with. Carbs are like 4 per gram, whereas Fat is 9 per gram. The expectation is that the satiation will be so high that you'll actually eat less. This does happens, but it can be defeated easily- so much so that I do not think nuts are a good diet food. Way too easy to overeat them. Also there was this trend to add fats to meals that really didn't need them- again probably a bad idea.

And then there's this whole issue of cheating. We are all going to cheat sometime. I would generally treat myself to ice cream or something after seeing the number on the scale going doing. This was somewhere between once or twice a week. I didn't know at the time, but have since seen some information that suggests this could reset some of the metabolic pathways, so that continued fat loss is possible.

Many more arcane points I could include here- like buy the expensive ice cream with ingredients your great-grandparents would recognize as actually belonging in ice cream- but this is kind of just a shot in the dark here anyway and probably too long for iris.