My daughter is almost 4 years old and is still a grazer and during growth spurts she eats more then I do in a day because they need a lot of food energy to growth. Grazing is actually healthier then eating big meals because the body is breaking down the food slowly instead of us cramming our stomach full.
We sit down for 3 meals (breakfast, lunch & dinner), my hubby tries to stress eating ALL of the meal in one sitting BUT with my daughter she will eat about half of it and come back 30-60mins later to eat the other half. I give her a smaller portion for dinner and then took something my mom did for me, she would put a muffin tin out on the table (or in fridge) with healthy foods to snack from. Usually it was fruit in two, veggies in two and the last two goldfish/cracker type snack (when it was completely empty it gets refilled, unless it is the end of the day/bedtime then it would get washed).
Daughters average eating times: Breakfast grazing 7:30am eats half comes back around 8:30am to eat the other half, Snack 10am, Lunch grazing Noon eats half 1pm eats other half, Snack 2:30pm, Dinner 5:30pm eats half 6:30pm eats the other half, Snack 7:45pm (bedtime shortly after 8pm). During growth spurts she is ALWAYS eating and never seems full, hence where the muffin tin with healthy food comes in so she can help herself instead of me getting something for her every 30 mins :)
My daughter is healthy, happy, in the 95% range for height, 50% for weight, smart and has a great personality. To me that is what matters, if it works for your kid and they are healthy great :)