5 meals is inherently superior to 3 in every regard except for one: 3 meals is easier (as long as total daily caloric intake is constant).
every time you eat a meal, your body expends energy starting the digetstion process, which also kickstarts other metabolic functions. this is one reason why, often people who skip breakfast gain weight.
also, you are spreading out nutrient intake, which is more efficient.
i take in 4 right now, but things have been crazy and i just havent had time for more than that lately. after things settle down after finals, im hoping to get into the habit of 6 meals a day.