I don't know. I've always eaten two full meals a day and a partial meal at breakfast. I'm very active though.
That (and just about any other pattern) works fine for people who don't have any trouble controlling their weight, and who don't have problems with hypoglycemia (which is often at the root of mild overweight problems). But for those struggling to lose weight or keep weight down, the frequent small servings throughout the day usually works best. The trick though, it not to let that schedule be an excuse for eating nothing but junk food. A diet consisting of a donut in the morning, a little bag of potato chips an hour later, then a candy bar, then a sugary soda, etc. obviously isn't conducive to long term weight control or good health. But with a bit of planning, many small healthy snacks instead of a few big meals can be a very healthy way to eat.