I have dropped down from size 18/20to sis 12 in 9 months buy using healthy keto and intermittent fasting

Just wanted to thank you for everything you do to help us understand how our bodywork. I have dropped down from size 18/20 to size 12 in 9 months by using healthy keto and Intermittent Fasting one day 1 meal and next day 2 meals, kale shake, lemon, ginger, and apple cider drink. I was 197 pounds and now 162. My goal is 140 pounds as I'm 5.1 tall, 53 years old with thyroid underactive since 17 years of levothyroxine tablet 175mcg to 50mcg now. Very slow metabolism. Very hard to lose weight in general, I'm not a big eater. But need to control my stress and keep trying with my nonalcoholic fatty liver which doesn't help with my T3/T4 conversation.