I am 5' 9.5 so 238 is far worse for me than for someone taller.
But I reversed all my diabetic symptoms by the 5th day of my 1st 8 day fast - Oct 26 2016. I was 186 or so that day. June 1st was when I started right after I got the pre-diabetic diagnosis.
But I fasted all the way to 142 on Jan 13 2017. After that random fasting/low medium carb and literally random diet has seen me float between 150 and 170. I am making a run @ 135 or so now. The reason I believe you need to get as low as you can - 6-7% BF is because insulin resistance goes up with weight loss because it releases a lot of fatty acids from the fat metabolism. Those have to drop to 0 for the insulin resistance to go away for good. That's my theory anyway.
Losing a little weight likely wont work atleast for me it doesn't.
Thanks.
Srinath.