A relative used IF to lose around 80lb, back to a normal weight. She was pre-diabetic, now is diabetic. Her experience was, if she woke up and ate, she would eat all day. But if she ignored her hunger pains until 1 or 2 in the afternoon, she ate a lot less. It got to the point where she was not even that hungry in the afternoon and ate only because she knew she had to eat.

I have never been overweight, so it's hard for me to say, but it seems like eating on a fixed schedule helps develop some discipline over hunger pains that overweight people may not have, or at least not much.