Fasting means different things to different people, so correct me if I’m wrong: it sounds as though you are gradually eating fewer meals, but still eating every day, is that right?
If so, it shouldn’t be a problem, as long as you are keeping your carbohydrate intake under 20 g/day and satisfying your hunger when you do eat. As long as you are letting your body dictate the quantity you eat, and not dictating to your body, you should not trigger what I call the “famine reflex,” in which the body adapts the metabolism to the food intake.
Previous posters appear to be assuming that you were talking about extended fasting, which is much eaiser to do once we are fat-adapted. At seven weeks in, you are probably on the verge of fat-adaptation, however, if not already there. How are your energy levels doing? Do you excercise? If so, how is it feeling, now?
If you are enjoying eating only one meal a day, you might find yourself quite naturally forgetting to eat on a given day, and that would be a natural introduction to extended fasting, which is basically anything over 24 hours. If you let your body be your guide, you should be fine. For various reasons, fasting does not trigger the famine reflex the way reduced calories do.
As far as weight loss is concerned, you seem to be doing fine. I would be willing to bet that at least some of the intial 20-lb. loss was fat, not just water, but do bear in mind two points: first, fat loss is never a linear process, and second, the scale is not always a reliable guide to what’s going on. What we want is to lose excess fat, but to preserve or even gain muscle and bone density. Lean gains can happen at the same time as fat loss, and this confuses the scale. So if your scale doesn’t change, but your clothes keep getting looser, keto is still working!