Eva, if you read my thread on Ramadan-like IF you'll see I chose for that approach as the Fast-5 made me feel very cold. Other people have noticed they start overeating too much once the fast is over, though this depends very much on how low blood sugar level will drop (too low and you'll be ravenous).
Even the 2x/day approach didn't stop me from feeling cold. Only adding back in a 3rd meal at 6pm so taking a 12hr fast overnight plus a 6-8hr fast in day time seems to work best.
It is said that for some IF can even increase maintenance, due to catecholamine release. For me it meant that thyroid downregulated metabolism too much.
I don't really believe that a body gets more efficient in absorbing foods when being given 1 or 2 meals, since the 'bolus' is getting bigger.
I do believe it's a good idea to give the gut time to rest, hence why I like skipping lunch after having kickstarted metabolism with breakfast in the morning. It's not like that I felt the need for eating coz' I'm hungry, which I'm not.. just the mantra 'eat your breakfast or ' .. except that it's a LC-breakfst not kiddie cereal w milk