Many people "graze" throughout the day, eating many small meals spaced every couple of hours or nibbling continuously throughout the day. They reason that grazing pre-empts the drop in insulin and blood sugar that occurs during longer periods of time between meals that can trigger greater appetite. They argue that grazing leads to lower calorie intake and perhaps weight loss.
But there are fundamental flaws in the notion of grazing, adverse effects that might even contribute to high blood pressure and heart disease.
Humans are not meant to graze. We are meant to track a wild boar or other animal, kill it, gorge on the meat, organs, and fat, then forage for berries, roots, leaves, and other foods until the next kill. A human living in the wild does not have cellophane-wrapped, preservative-containing snack foods, nor a cupboard or refrigerator full of ready-to-eat foods to graze on.
Grazing is a consequence of a world filled with carbohydrate convenience foods: crackers, pretzels, granola bars, muffins, bagels, chips, etc. After consuming one of these common grazing foods, blood sugar and insulin head skyward, only to fall precipitously. The cycle takes 90 to 120 minutes, just in time to trigger the impulse for the next bout of grazing. In other words, with carbohydrate convenience foods, grazing is almost a necessity to avoid the fatigue, fogginess, and low blood sugar that develops after carbohydrate foods. (Yes, this includes modern fruit.)
Such sugar-insulin cycles are not healthy. They trigger artery constriction, expose the body's organs to high blood sugars ("glycation"), and pack on abdominal fat. It also takes you a few steps closer to diabetes.
There's another important argument against grazing. The several hours after a meal are the most dangerous for creating coronary atherosclerotic plaque, i.e., the post-prandial period. In other words, eat dinner and, for the next 6-12 hours, your intestinal tract degrades the food; food byproducts are absorbed into the blood or lymph system. The blood is literally flooded with the byproducts of your meal. Postprandial abnormalities are emerging to be a potent, and much underappreciated, means of causing heart disease and atherosclerosis in other vascular territories (especially carotid arteries and thoracic aorta).
Grazing means that you are continually in a postprandial state. Blood vessels are filled with the byproducts of your last grazing snack, followed without rest by the next snack. This simply cannot be healthy.
The converse of grazing, or not eating - i.e., the fasting state - for extended periods is good for you. The Mormons, for example, who commonly fast one day per month, have substantially less heart disease than other Americans who don't fast.
Encouraging people to graze amplifies atherosclerotic risk, since it creates an abnormal prolonged postprandial state. The solution: Avoid convenience carbohydrate foods as much as possible and the grazing impulse will diminish.