Fasting as a weight loss strategy

Good morning! I have many questions but the first is, what is meant by "18:6"?

18 hr fast with 6 hr eating window. generally, we eat 1-7pm

From the limited information I gather that the restricted food intake period for you was mostly based on health concerns. It seems that you were very successful. For several years I have consistently kept a 12 (or more) hour of fasting time between the last food intake of the day, and the first in the morning. Even that limited time of no food (“good” stuff, since I dislike cookies, potato chips, etc., but also no yoghurt, dark chocolate, nuts, even fruit after 7PM) does make a difference. It does screw up the social life sometimes when we go out for dinner, but basically it’s good for the digestion, and sleep. And whenever I eat, I eat slowly, and try to savor it. Initially forced to do this by repeated rounds of invasive gum/dental work, but just slowing down, while eating the same foods, but slower, I dropped 15 lbs. off a normal weight, and kept it off for 2 years. However, after recent surgeries, or even in general, I have no problem going 24 hours without food, at all. Not on a daily basis, but again, not a big deal.

Interesting TED Talk on fasting...
Fasting for Longevity
An enlightening and provocative presentation is given by Valter Longo updating audience on the benefits of fasting for life-extension.