After about 6 months out I certainly found that my diet had a much more noticable effect on my weight loss. All this means though is that if I have a big week (say like for my birthday) where I eat more junk than normal I don't get too comfortable with it because I see it on the scales.
So if you were maybe eating more carbs or calories than you should have been it wouldn't really have mattered that much int eh first 6 months, you will still lose weight, as you get further out you can't get away with it and lose weight.
Perhaps have a look at your food for the last week and see if you are following your providers guidance.
Hope you work it out, good luck.
Also well done with your losses so far!
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