There was an article in the Wall Street Journal on 9/8/10 entitled How Lunchtime Is Turning Into Snack Time. It discussed how there's a blurred line between what constitutes a meal vs. a snack. Americans consider almost anything a snack these days, as opposed to being an appetizer, side dish or something else. In addition to what kind of food is a snack, the time of day it's eaten can define something as a snack vs. a meal. Americans eat any time of day or night these days, which is a boon to the fast food industry, which is experiencing a huge increase in the amount of sales generated between traditional meal times. Nutritionists have always said it's better to eat several small meals, rather than 3 big ones.
However, the article did not get into the calorie consumption and lack of nutrition involved in all this junk food snacking! No nutritionist would recommend eating several 300-400 calorie, junk food "snacks" in addition to three meals a day! This is why 2/3 of the the American population is overweight or obese! Too much junk food! Both too much and junk food! It's exactly the opposite of what our bodies need: fewer calories and more nutrition.
Food nutrition labels always give their information based on a 2000 calorie diet, which may be more or less than what any individual actually needs. You can check how many calories you need at My Pyramid Plan. Just enter in your gender, height, weight, age and activity level. It said that I need 2200 calories to maintain my current weight, but 1800 calories if I didn't already exercise. If I was 20 yr younger & didn't exercise, it said I needed 2000 calories.
How many calories is the typical American consuming? Far too many! The article gave the example of the Angus Deluxe Snack Wrap from McDonald's, which has 410 cal, a mere pittance compared to the full-sized Angus Deluxe burger, which has 750 calories. However, compare 750 calories to a daily recommended total of 2000; that's more than 1/3 your daily calorie intake in one burger, not including fries and a drink! Multiply that times three meals and add in a couple 410 calorie snacks and you've consumed 3070 calories, 1070 calories more than most people need! Eating like that, you will gain 1 lb. every 3 days!
The other issue is the lack of nutrition junk food provides. MyPyramid focuses on the food groups and how much you need to eat from each food group. The different food groups provide different nutrients your body needs. The more variety, the better. We, humans, are lucky in that our bodies can make use of an enormous variety of plants and animals to nourish our bodies, compared to many animals that eat a very limited diet. In fact, if we eat a limited diet, we are likely to be missing valuable micronutrients our bodies need. Junk food provides an excessive amount of fat, sodium and sugar, carbs and protein, but insufficient amounts of the many vitamins and minerals our bodies need to performs important functions. Different colored foods provide different nutrients as well; for example, red vegetables contain lycopene and orange ones contain beta carotene, which are both important for our bodies. So it's important to eat a colorful diet! The more color, the more nutrition. Have you ever noticed that junk food tends to be brown? The only colorful things on a hamburger are the lettuce and tomato, the healthy parts!
The "take away" from this is: no matter what you eat or when, or whether you call it a snack or a meal, focus on limiting calories and increasing nutrition.