Both are right. Time fasting is very good for body. When you are in fasted state, fat burning happens. Insulin helps in fat storage. But when one is out of fasting stage and is eating, one should eat smaller meals frequently. Logic is, by eating smaller meals will lead to lesser insulin spike and lesser fat storage. Insulin levels will be in steady state, neither too high nor too low. Sometimes Drs and dieticians do not stress
much on fasting time. But one must definitely have at least 12 hrs gap between dinner and next breakfast. It is only after 12 hrs of fasting, fat burning process starts. Hence it could be 13-16 hrs as well depending on your goals.