To effectively lose weight over the long-haul fasting and only eating one meal a day and "diets" or fad diets won't cut it. Our bodies need to "graze". Eat smaller meals throughout the day and watch the weight slough off.
By only eating one meal a day your body wants to retain everything it can because it gets fed only once a day. Get your body used to eating all of the time in small amounts and it then no longer needs to hold on and can burn off what it thinks it doesn't need.