The thing with only 1 fast a week is that you will still have to eat at or below your TDEE on eating days. Its easy to eat 2 days worth of extra calories over 5 days and not lose or even gain weight. Alternatively you could do 2 to 3 48 fasts a week with1 meal in between which should show speedier results.
I fast more than that, but in 48-72 hour chunks as I have a lot of weight to lose. For fat loss, CICO is still king. Fasting is a tool, and not the key to weight loss by itself.
If you’re eating under your TDEE and fasting 1-2 days a week, you should lose .75-1.5 pounds a week. Depending on your starting weight and height and activity level, this might be more or less noticeable. The change you see is also dependent on how much you have to lose (paper towel effect). I will say I’m less bloated after a fast though! I’d try taking measurements or pictures and compare, along with the scale.