A new study out of Italy may shed some light on this phenomenon. Quoting from Medscape, "Scientists from three academic labs in Italy found that levels of ghrelin, [...a hormone that stimulates appetite] rose substantially in eight healthy volunteers -- who had already eaten a full meal -- when they were allowed to eat as much as they wanted of their favorite food. No such increase was seen when, under the same conditions, the same volunteers were told to eat foods they didn't like but that had the same calorie content." In layman's terms, our brains respond positively to foods we like to eat and therefore we are able to keep eating such food even when we are not hungry.
Another popular belief is that Europeans are more sophisticated eaters than Americans and relish their food more than we do. Indirectly, this Italian study would appear to support that contention. When it comes to food, most Americans are not very discriminating. Exposed to many foods from many different cultures, we seem to like the variety, and so we develop a wide range of tastes. The panoply of food choices available to us at any given time stimulates our appetite as we seek to determine what we will choose next. The Italian study therefore demonstrates why we may over-eat. The more foods we like, the more foods we eat. The more we eat, the heavier we get.
There is a concept called habituation that explains this phenomenon from another angle. Habituation means that we become accustomed to our foods. The less types of foods we eat, the less of that food we need to be satiated. In light of the Italian studies, this makes sense. The more foods we like, the more foods we eat. The fewer types of food we regularly consume, the less of it we hunger for.
On a personal level, this has worked for me. At 50, I was diagnosed with calcification around the heart, a sign of impending disaster. I was overweight, popped pills every day for reflux and irritable bowel syndrome, was on a statin for cholesterol near 300, and couldn't run 50 feet without limping the rest of the day. I was your typical middle-aged American male. When I began to pursue MDPrevent in 2010, I was exposed to the science that changed my life. I learned that changing one's lifestyle, particularly how you eat, can change your life trajectory.
I now religiously eat the same breakfast and lunch every day. Breakfast is comprised of sliced bananas, blueberries, Bob's Red Mill Muesli, an organic cereal like Ezekiel Almond or Nature's Path Flax, and a glass of Blue Diamond Vanilla Unsweetened Almond Milk. I eat in a small bowl and I am NEVER hungry before lunch. For lunch, I eat hummus on Arnold's Whole Wheat Thins (has preservatives) or Ezekiel bread (no preservatives - found in freezer section), topped with spinach and sometimes olives, and over the next or so hour afterwards, I snack on sliced apples, a small bag of carrots, and a bag of mixed nuts. Again, I am NEVER hungry before dinner and I am not even famished by dinner time. For dinner, I try to eat wild fish like salmon or cod, with quinoa and mixed vegetables and for dessert, I enjoy sliced melon.
This food routine has allowed me to shed 20+ pounds, eliminate my reflux, my irritable bowel syndrome, stop my statin and still reduce my cholesterol to less than 150, move out of the pre-diabetic range, and also practically eliminate my hip osteoarthritis, which allows me to run for longer distances than I have in 20 years.
I am not saying that one has to eat exactly what I eat, but the facts remain that the less variety of foods I eat, the less I crave.
So if you want to stay healthy, get healthy, and keep the grim reaper waiting, consider narrowing down your food choices to a select group of healthier foods because the less foods you choose from, the less of those foods you will need to be satiated, and therefore, the less of those foods you will eat. Become a more discriminating eater and you will most likely also become a healthier one as well.