No, that's not true.
Each individual person is different based on their own unique BMR, plus also what you've been doing in the last few hours before the meal.
Almost everyone eats more in any single one meal than your body requires for energy Right Now. It converts the excess to fat. But later in the day, while you're going about your regular daily business, it's converting that fat to energy to power you through.
You don't need to worry about what turns to fat or not in any single given moment, only the trends over time, with a hope towards creating a deficit overall so that your body, throughout an entire week, will pull more energy from stored fat than it puts back into stored fat.
However, if most of your calories are consumed in 1 meal, you do want to think about whether this causes you to be hungry at other times of the day. Most studies find that people tend to do better with losing weight by spreading out their intake over the day a little more balanced. That may or may not be true of you personally, but if you're struggling to lose, it's definitely something I'd consider.
Edited by: UNIDENT at: 3/11/2013 (00:55)
Deb, in New Zealand