In this section, we discuss the various sensations that come from food, and how they may affect your diet.
The reasons why certain sensations are important in dieting are very speculative.
But there is little doubt of the fact that they are important. A large body of replicated research has demonstrated this conclusively.
Fortunately, both modern and traditional food techniques make managing these sensations a simple process.
We discuss which sensations that are important; why they may be important; and how you can use food to include them and make your diet more satisfying..
Serious dieters have long known that certain food sensations are important to successful weight loss. For example, an intense craving for sweet food is almost inevitable at some point on a diet.
The importance of food is not just due to nutrition. Several sensations that food provides the body are also important. This means that using food to manage these sensations is important for diet success.
Science is not sure why certain sensations are important, but a large number of replicated mainstream experiments over the last two decades confirm that they are important and that this importance is at least semi-independent of the nutritional value of the food.
There are three sensations that most need to be managed.
The sweet sensation is one of these. Dieters who try to do without anything sweet for long periods of time usually experience intense sweet cravings and this makes it very difficult for them to stay on their diets long enough to lose much weight.
The occasional feeling of having a full stomach is also important. This sensation of a large quantity of food in the stomach is created by a combination of the volume and weight of the food eaten. People who eat nothing but tiny quantities of food to try to lose fat almost always have difficulty because of this need.
The desire for a variety of different foods also seems "built-in" to the human makeup. People who try to lose weight simply by eating the same bland "diet stuff" day after day usually run into trouble. This sensation of variety has been found to be controlled by a combination of food flavor, texture, "chewiness", "crunchiness", "mouth feel" and so forth.
Experience shows that the desires for these sensations never goes away entirely, although these desires are much less intense when dieters manage the purely nutritional food factors properly.
This means that successful dieters must know how to use food to manage these sensations in addition to managing nutrition.
Fortunately, there are many easy ways to manage each of these sensations.
In addition to being a source of nutrients, food has psychological... values that are important, though difficult to quantify.
Food and Nutrition Board,
National Research Council,
National Academy of Sciences (U.S.)Recommended Dietary Allowances (10th ed. 1989)
Exactly what do we mean by “The Sensory Factor”? Well, to begin with, we are not talking about “conditioned responses” or “neuroses” or any such standard psychological concepts.
Decades of sophisticated research have been expended on trying to find out if neuroses, conditioned responses, or other such things somehow “cause” obesity and overeating.
The results have been overwhelmingly negative. These concepts have simply not proven to be particularly useful for understanding or answering the question: “Why do some people gain too much fat?” (In fairness, however, we should acknowledge that “much truth is found by a process of elimination”. The decades of work on these issues eliminated a lot of “false trails” about the causes of obesity and additionally produced a great deal of useful data for other things.)
If you would like an excellent, non-technical, and very readable discussion of the history of some of these approaches to explaining obesity, I recommend William I. Bennett’s The Dieter’s Dilemma, which discusses in very readable detail the various hypotheses of these types explored and the results (mostly negative) obtained. Bennett’s book also presents the concept of the “set-point” which, although flawed in my opinion, still contains one of the central roots of threshold theory. (See the discussion of set point theory.)
The diet Sensory Factor (like the Exercise Factor) is a non-nutritional factor that nonetheless strongly affects both hunger and eating. This means it must be both understood and managed if you intend to succeed in staying on your diet long enough to lose much weight. Fortunately, the techniques are easy to master once you understand the issues.
What I call the Sensory Factor in dieting involves three different “sensations”. Each of these sensations strongly influences eating in a different way. These sensations are the sensation of “quantity”, the sensation of “variety”, and the sensation of “sweet”. Extensive research over the past 20 years has demonstrated that human beings have consistent innate responses to these sensations and these responses in turn have strong effects on both hunger and eating.
The easiest way to explain what I mean by the Sensory Factor is to say that the primitive sub-mind I have labeled hunger has certain “expectations” about food that have been “built in” to its makeup by evolution over the last 500 million years (give or take a fewJ). Since they are built-in, you can't ignore or change them—you must learn instead to manage the factors that control them. These expectations do relate to physical nutrition, but only indirectly.
The theory behind the Sensory Factor takes a step beyond simple physical nutrition by stating the following:
Your body needs the vital chemicals it gets from food (i.e. vitamins, minerals, protein, EFAs, etc.), because without them… you’ll die.
In 500 million years of evolution, your body has also learned to use certain of the “sensations” naturally associated with foods—such as their flavor, texture, sweet, weight, volume, etc.—as cues to help it properly manage your intake of these vital chemicals.
Research has found that certain food-related sensations have consistent effects and may therefore be used for very specific purposes. We can speculate that the body “expects” to be able to use these sensations for certain purposes and tends to get “confused” or feel “deprived” if you continually eat food which doesn’t satisfy them properly—as is often the case on simpleminded weight-loss diets.
Of course, the actual physiologic mechanisms by which your body “expects” these sensations, feels “deprived” without them, and then “stimulates” your body into action to get them, are completely obscure (certainly to me), and I’m sure many Nobel prizes are waiting for those who can do the “heavy-lifting” in researching this.
But basic facts which are undeniable are that humans like the sweet flavor; that they like the sensation of having eaten “enough” food; that they like eating a variety of foods—and that they will eventually break off a diet in order to get these sensations.
Of course, as a practical matter, once you get the purely physical nutritional factors under proper control, you will find that your body will be much less “fussy” about the Sensory Factor. But experience shows that it won't ever let you totally ignore the sensory qualities of food. If you try to do so, you’re likely to wake up one day finding yourself gobbling handfuls of “sugar-coated red-pepper pickle chips” or some other strange food item that you don’t need.
All the recommendations in this chapter assume that you have already mastered The diet’s physical nutrition factors and that your body is therefore not making you hungry in order to get some specific nutrient. All of the Sensory Factor needs are really very simple to manage—if they are not being stimulated by true nutritional insufficiencies.
What are these sensations and how do we handle them to help ourselves lose weight?
Most people have noticed that when their stomachs get full they stop being hungry. (Duhh!!) In other words, quantity—by which we mean the feeling of being full—is a sensation that directly influences you to stop eating. (Formal experiments have also demonstrated that it is distention of the stomach that ends eating.)
This is potentially a very useful effect for someone trying to lose weight. However, it’s one of those things that are so obvious that people rarely ask the question: “How could I use this effect to help get thinner?” (Fortunately, some researchers do ask questions like this.)
Before I try to provide answers to the above question, I’ll speculate a little on why this sensation of quantity shuts off hunger. According to the threshold theory, hunger is triggered whenever body supplies of any nutrient fall below “preferred” (threshold) levels. Hunger and its associated eating are turned off again when supplies of that nutrient have been brought back up to “normal” levels. So how could a transient sensation such as “fullness” affect this purely metabolic process?
In my opinion, the answer is that the Quantity Sensation is probably part of a safety shut-off mechanism. An example may make this idea clearer.
Let’s say your body falls below its desired threshold amount of (e.g.) potassium. When this happens it makes you hungry and you go find some food and you start eating. To keep the example simple, let’s say you find food that actually does happen to have a lot of potassium in it. This means that as soon as that food is digested your supplies of potassium will be back up to the proper levels and your hunger will be turned off.
But notice the problem here. Digestion may take several hours—so it will be at least that long before potassium levels are restored to normal and your hunger can be “turned off” by this method. Such a delay means that you could remain “hungry” and therefore continue to be stimulated to eat for several hours even though the first few bites of the food were actually enough to take care of your real nutritional need.
Obviously, if you actually did eat unnecessarily for several hours you could stuff yourself to the point of causing digestive damage or poison yourself with far too much potassium for your body to handle after it was digested. At the very least, your hunger would keep you focused on the wrong thing (food) for far too long and thereby waste a lot of time and energy—which is itself not a strong species survival trait. Clearly, the body needs a “temporary hunger override mechanism” to prevent such effects.
It is quantity—the sensation of a certain volume and weight of food in the stomach—which seems to provide the needed safety override. This sensation shuts off hunger even though your body’s supplies of (e.g.) potassium are not yet back up to normal levels (because the food you ate has not yet been digested). This safety override prevents the above problems.
During the last 500 million years, vital nutrients have probably most often been available only on a “feast or famine” basis, or in very low quality food, so we can speculate that your body “expects” to have to use this override mechanism quite often.
In any case, the sensation of “filling yourself up” with food at least once a day is clearly very satisfying to most people and certainly makes it much easier to stay on a diet. The obvious warning to dieters is that you must do the “filling up” with low-fat, low-calorie food that also provides a lot of the non-energy nutrients that are what your body really wants.
Note that the quantity sensation is only a temporary hunger override. If you need (e.g.) potassium, but fill yourself up with food that has very little potassium in it, the hunger will quickly come right back as soon as the food is digested, and the full sensation goes away, and your body finds out you’re still low on potassium. When this happens, it means you ate the wrong thing and gave yourself calories instead of what you really needed. Your body will then make you “do it over ’til you get it right” (kind of like your third-grade schoolteacherJ).
According to threshold theory, this common sequence of events (“eat wrong, eat more”) is the underlying cause of weight gain. Learning to consciously reverse the sequence (“eat right, eat less”) is the means to lose that weight.
On the diet, you do not “starve” yourself for quantity. Below you will find some ways to use this powerful hunger shut-off mechanism without getting a lot of calories in the process.
Food research specialists have long known that flavor, texture, density, and other sensory characteristics of food are necessary in order for the food to be satisfying when eaten.
Experiments using tubes to feed people and animals so that they couldn’t taste, chew, or swallow their food show that when this “pregastric stimulation” is missing, people tend to eat more and feel less satisfied.
Experiments testing the opposite situation (tasting without swallowing) show that taste alone can raise the metabolic rate, release insulin into the blood, and directly cause several other physiological changes.
In other words, the sensory characteristics of food are not irrelevant. They have powerful effects that will affect eating behavior whether we like it or not, so we must learn how to use them properly.
Even without tube feeding, it just isn’t very satisfying to continually eat the same bland meals over and over. Yet despite this, bland meals are just the way dieters are often advised to eat. (You know the drill: cottage cheese, salad, plain poultry, fruit, etc. You are often advised to eat this way exclusively, sometimes for weeks!) At least one prominent researcher (Schiffman 1993) has pointed out that this causes a “deficiency in orosensory stimulation” which makes these foods unsatisfactory from a sensory viewpoint. In The diet we simply say your body “expects” various sensory stimuli and feels “deprived” without them—even when it’s getting normal amounts of good, nutritious food.
In my humble opinion, yor body wants and needs the sensations of flavor, texture, and density because these are the cues it uses to “keep track” of just what foods you’ve eaten and how much of them you’ve had recently.
For many decades, researchers have been able to demonstrate that the desire to eat a variety of different foods seems to be “built-in” to human nature at a very basic level. The likely reason for this is that no single food found in nature contains all the nutrients needed to keep humans or most other creatures healthy. Therefore, we need to eat many different foods within a short period of time to get enough of all of the right things. Our primitive “reptilian-mind” knows this.
Furthermore, your body knows that you can poison yourself with certain otherwise vital nutrients if you eat too much of one food or eat it too often. The desire for variety therefore probably evolved to stimulate primitive creatures to move on and find something else to eat instead of just staying in one place and eating whatever food is there until it’s gone (which would always be easier and usually safer). How then does your body “motivate” you to move on to eat something different?
I have said previously that your body makes you hungry whenever you “run low” on any nutrient you need to stay healthy. However, merely being hungry doesn’t necessarily mean you’ll eat the right thing to get the nutrient you need—particularly if you happen to be a primitive human creature with little reasoning ability. But eating a lot of different things increases your chances that at least one of them will have some of what you need.
Here is another example to try to make the point clearer. Let’s say you’re a primitive creature who’s camped out under an apple tree eating apples. After a day or so your primitive sub-mind makes you hungry because you’ve run low on some nutrient you need. But it’s not likely that eating more apples will give you much of whatever you’ve run low on, because if it would, you’d never have run low on that thing while eating apples in the first place.
So there’s no survival value in wasting time or energy filling yourself up with more apples even though they are readily available. (As we saw above, this would shut off hunger temporarily but would not get you whatever nutrient you needed.) So how does the primitive reptilian-mind stimulate you to move on to find something else?
Since at least 1934, researchers have noticed and extensively investigated a phenomenon they have named “sensory-specific satiety”. This is a descriptive term that simply means that as you eat one particular food, you very quickly (within about two minutes) begin to stop liking that particular food as much as you normally do. This effect is only temporary. It lasts about an hour.
But sensory-specific satiety only affects the food you are eating at the moment. You continue to like other foods just as much as normal. So the practical effect of sensory-specific satiety tends to be that you stop eating the food you’re eating and instead go on to try other foods (if they are available).
In other words this is a major inborn mechanism to unconsciously stimulate you to eat the variety of foods that you normally need in order to stay healthy.
“Sensory-specific satiety” can be viewed as your body’s way of telling you what foods you probably don’t need to eat any more of. But how does your body guide you more precisely toward what you do need to eat? This is where we begin to reach the “modern-day” limits of your body’s capabilities.
There is a large amount of research demonstrating that when we are deficient in a given nutrient we quickly and unconsciously learn to like the flavor of any food we happen to eat that has this nutrient in it.
This “learning to like it” reaction has been shown to take place a few hours after eating the food. Using our diet terminology, we can say that your body is smart enough to notice that what you ate several hours ago gave it the nutrients that it actually wanted at that time. So it turns on your “liking” for that food. This “liking” very probably helps you select that food again whenever you need some of those nutrients. Thus your body does have a certain very rudimentary “learning capacity”.
However, please note that this can create a potential problem for dieters. Suppose your body has learned to associate (e.g.) potato chips with satisfying a need for more sodium (salt). Is eating salty potato chips a good way to get sodium? It sure is! Is it a good way to stay slim? Not hardly!
In other words, left to itself, your body will often learn to “like” a lot of things that not only have the nutrients it needs but also lots and lots (and lots) of calories that it doesn’t need.
Your body isn’t much concerned about getting too many calories because it has an almost unlimited storage capacity for them—in that ample adipose reserve you’re already carrying around! It also knows that you’re certain to need those stored calories during “the next scheduled famine”. However, in modern societies, famines aren’t scheduled that often anymore, so the calories just keep accumulating.
This is the reason a higher-level mind (you) needs to consciously enter the picture and become a “Body Trainer”. Using diet principles, you can deliberately introduce your body to foods that you know have lots of nutrients but very few calories. It will quickly learn to like these foods just as much as the foods with all the calories. It doesn’t really care that these new foods don’t have many calories because it knows you have a several months supply of calories that it can use for your energy needs.
It is interesting to note that your body is a true “idiot savant” Within its own very limited area of competence—the monitoring of your internal nutrition status—it far surpasses you. Outside of that area of competance, it badly needs your guidance. The diet teaches you how to give it the right kind of guidance.
Even with the purely nutritional factors under complete control, it’s difficult to go more than a few days without eating something sweet. If you try to do this, you will begin to crave sweet things—jellybeans, double-fudge ice cream… or the famous "diet" Chocolate Cheesecake.
Scientists have demonstrated that humans and many other species have a strong innate preference for the sensation of sweet. Research has found this strong preference for the sweet taste in animals, newborn infants, and across human cultures. Additionally, when given the chance, humans tend to increase their intake of sweet things. For example, the world production of sugar rose from 8 million tons in 1900 to almost 110 million tons in 1990—a much larger increase than seen with any other food.
In my opinion, the probable reason for this preference for sweet is that in the natural environment, sweetness is a cue for safe edibility.
Despite the clear preference for the sweet taste, research during the past decade has found a surprising disconnection between sweetness and the quantity of food actually eaten. Even though humans have a strong innate preference for the sweet taste, experiments show that neither appetite nor total food intake is particularly increased by the sweet taste alone. So even though you probably like the taste of sweet, it doesn’t necessarily make you eat more food, (all other things being equal).
This finding has been surprising because the usual presumption is that we like sweet because it indicates the presence of sugar—which is a source of energy—and obviously we need energy.
But despite this presumed connection, experiments seem to show that the pleasantness of the sweet sensation is only very weakly connected to appetite or the desire to eat. Perhaps a rough comparison might be to the pleasantness of smelling a sweet perfume—which generally does not stimulate appetite (at least not the appetite for food).
The experiments that demonstrate the above-mentioned disconnection have commonly compared the effects of sweeteners that have calories (usually glucose or sucrose) to sweeteners that have no calories (usually aspartame). Generally, these experiments have shown that people who eat things that are artificially sweetened do not eat more later than the people who eat things sweetened with sugar. In other words, people don’t necessarily “make up for” the calories they didn’t get in the aspartame by eating more food with more calories.
So we love the sweet taste, but it doesn’t make us eat more food (all other things being equal). This is an apparent contradiction. Fortunately, there is a very intriguing explanation (though admittedly it’s completely speculative).
Translating into diet terminology, we can say that the primitive sub-mind we call “hunger” seeks out the sweet flavor because this is its cue that it’s found something edible—meaning safe to eat (and usually a plant food).
In other words, the sweet sensation tells your body that it has found a food that is probably not poisonous. I suspect that the sensation of “pleasantness” that we feel is your body’s reaction to the presumed safety of the food rather than to the energy or other nutritional content of the food.
This suggested mechanism is entirely consistent with threshold theory, which states that the need to eat (hunger) can be triggered by a lack of any essential nutrient, not just by a need for more energy. Most edible plant foods provide many of these essential nutrients besides energy. So a specific trigger for energy would probably “miss the mark” in most cases. For a fascinating review of many of these issues see Ramirez, 1990). Other specialists have made similar points.
There is one further point that is particularly good news to dieters. In addition to the above-mentioned more general experiments, there are several reports of specific experiments testing the use of aspartame which concluded that aspartame (a very low calorie sweetener) makes it easier to stay on a weight-loss diet.
These experiments found that you can stay on a diet more successfully with aspartame than without it. In each case subjects who were told to use aspartame on their low-calorie diets were able to stay on the diet and “cheat” less than subjects who were told not to use it. These experiments were not designed to test diet ideas. However, their conclusions do support the contention of threshold theory, which states that providing “hunger” with all the things it wants (one of which is the sweet flavor) while also restricting calories will prevent it from forcing you off your diet before you can lose any serious amount of weight. All of these points mean that we dieters can have the sweet sensation we like without the negative effects of sugars (i.e. the calories, the high glycemic index, or the insulin overreaction) simply by using artificial sweeteners.
The technique of course is simple—use aspartame! It has an insignificant number of calories and no known negative effects under ordinary circumstances.
(Note: Some people may be mildly allergic to aspartame. If you feel that it may be “unbalancing” you in some way, there are other high-intensity artificial sweeteners that probably work just as well for this purpose. And of course you may always use natural sweeteners if you make sure you count the natural calories that come with them)
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