Why we get hungry: Module 1, Part 1: Full report

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1 Why we get hungry: Module 1, Part 1: Full report Print PDF Does Anyone Understand Hunger? Hunger is not simply a signal that your stomach is out of food. It s not simply a time when your body can switch and decide to start burning fat calories. It s not a simple annoyance you may or may not be able to overcome. It s none of those. Hunger is a complex set of signals that come from your body and go to your brain where they get processed. After processing, they leave your brain. In the case of hunger, the messages that leave your brain say one of two things: 1) Everything is great; or, 2) We are starting to get hungry. In the case of Everything is great you are compelled to do nothing. You may not realize it, but you are. Signals from your brain mean everything is ok, so there is nothing to do. In the case of the latter, you seek food. Unfortunately for most of us, the part where we are compelled to do nothing only really occurs after eating a meal. And we are typically compelled to say: I m done with this! You start thinking about what you are going to do and this and that. But then, it s time for the next meal and you forget until you are done eating. So you go through this cycle. Seemingly forever. We want the compelling part to tell your body to do something and not you. We don t want you to be compelled. That involves thinking, which can be a problem. Not in a general sense, but in a response to hunger sense. When most people process hunger they think about what to eat, which usually leads to a bad decision. So you can go back to your normal thinking, we just want you to think less about food. The ideal scenario is to be compelled to do nothing. This has many benefits because if your body isn t the least bit hungry, you aren t even thinking about food. Thinking about food is where things get difficult. We can think whether or not we want food, we can think whether or not we like a particular food or we can think if we re even hungry at all. Thinking these things is the problem, because it will compel us to seek food. This is how this whole process is complex and complicated. Complex because several disciplines of science are involved, including biochemistry, psychology, neuropsychology, neurophysiology and more. Complicated because we are humans; more involved and somewhat different than laboratory rats! But let s be clear on one thing, these complications and complexities mean that hunger is NOT some annoying signal we can choose to ignore. Hunger makes us human. If we never got hungry, we d waste away and die. Not an ideal situation but an indication that hunger is necessary for survival.

2 So what makes us hungry? Are there ways we can deal with it? Can we eat in such a way to control those signals from our brain that compel us to seek food? If Your Cells are Hungry You are too. At its most basic level, signals from your body travel to your brain and indicate nutrient status, which means how full (or empty) your cells are with nutrients. If the nutrient status of your cells is full, it is less likely your brain will send hunger signals to your body, compelling you to eat. If the nutrient status of your cells is empty (or the emptier they get), it is more likely your brain will send signals to your body, compelling you to eat. This oversimplifies things, but if you eat foods that feed your cells, hunger will diminish and maybe even go away. Liking and Wanting We will tread in the waters of oversimplification, in attempt to better explain what is going on. We won t jump heavy into the science, choosing to remain topical and conversational. To get started, we have to differentiate between liking and wanting. There are several components to hunger, we re starting with these two: liking and wanting. What s the difference? Let s illustrate with bacon, almost everyone likes bacon (who are those people that don t?). But because almost everyone likes bacon doesn t mean we always want bacon. Maybe we don t want bacon because we are full, had bacon again for breakfast (for the 8th day in a row) or maybe we just want something else. Liking a food means we anticipate some level of pleasure from eating it. Maybe it s the flavor. Maybe it s the crunch. Maybe it s both. Doesn t matter. It s something we like. But because we like it, it doesn t mean we ll always want it. We can say the same thing about ice cream. It tastes good. We like the cool, creamy sweetness of it on a hot summer day. We can anticipate how it will taste and how it will make us feel. This anticipation part is key, especially to Module 2, where we discuss hyperpalatabililty. Wanting a food, on the other hand, is different. If we want bacon or ice cream, we have some desire to eat some. If you really want some bacon or ice cream, there is almost no limit to which you will go to get it. If, on the other hand, you don t want any, you have no

3 desire to go out of your way and get some. When you think about liking and wanting this way, it makes sense. Wanting a food has no effect on whether you like it. Conversely, if you don t like a food, you ll never want it. So we ve started with two components of hunger: liking and wanting. Liking means you have a pleasurable anticipation for eating a food. Wanting reflects some level of your desire to acquire a food. This leads us to another set of definitions, because liking and wanting do not cover everything. Remember, we are human and have the ability to think. For example, you can be full after dinner but still want a bowl of ice cream. Wanting a bowl of ice cream after you ve eaten has little effect on whether or not you like it or whether or not you are full (Module 2). Satiety (sated) and Satiation (satiated) These are very similar words with distinct differences, which can be confusing. We will do our best to keep the definitions and examples clear, so there is as little confusion as possible. Webster s defines satiety as the quality or state of being fed or gratified to or beyond capacity. Easy enough, but it can be a bit of a problem when it comes to food and nutrition. Psychologically speaking, state means temporary. So in terms of food and nutrition, satiety is the temporary quality or state of being fed or gratified to or beyond capacity. Most of us can relate. After a big meal, we are sated. Our satiety is high because we are full. But this is only temporary because in a few hours, we ll be hungry again. When hungry, satiety is low. We are no longer sated. The problem is we are using a psychological term, state to define a physiological outcome, the extent of hunger. And the result of this problem is that we conclude hunger is all mental or willpower. Recall from earlier, if your cells are hungry, you are too. If anything, satiety is a reflection of nutrient status. More specifically, if nutrient status is high, the response is we are full. In practical terms, first understand: digestion and nutrient absorption are scientific terms, physiological processes. This means they can be measured objectively: How much? How fast? etc They are not psychological states. As such, there is no willpowering your way through hunger. Cellular hunger won t let you do it. There is no Jedi mind trick to satiety. Remember, satiety is a response from our body (specifically the small intestines) indicating some level of nutrient absorption. High satiety means we ve absorbed a lot of nutrients. At this point, we will be sated. Low satiety means little absorption; we will not be sated.

4 This leads us to our final component of hunger for this Module: satiation. To start, Webster s doesn t have a definition for satiation. It falls back to satiety. See? It can be confusing. Satiation indicates a state at which you have no desire to eat another bite of food. So the closer you get to being satiated, your desire to stop eating increases. So what causes you to be fully satiated? There are only two explanations: you are either full, full, full or sick of the foods you are eating. No matter. In either case, you are satiated (Note: this could be the same or different as being sated our previous definition we ll explain!). Let s illustrate with another example. Suppose you try a 30-day experiment in which you only consume Pepsi and Twinkies. After some time (maybe even the first day), your satiation will be high. Why will you be satiated? It s not because you are full or sated. It s because you are sick of Twinkies and Pepsi! You simply don t want any more of either. But you wouldn t be sated because Twinkies and Pepsi are nutrient deficient, containing little more than sugar and hydrogenated fats. This will leave your nutrient status low or your cells hungry; despite this, you won t eat because you are satiated sick and tired of Pepsi and Twinkies. So what happens at the end of the experiment? Because you are satiated but not sated, when the experiment ends, any food that you like will become a food that you really want (as long as it s not Pepsi or Twinkies). And, because your cells are really hungry, it s likely you will want foods to replenish your nutrient status. To illustrate this in another way, let s put a twist on the experiment by replacing Pepsi and Twinkies with liver and tap water. You will be satiated quickly, just as in the previous experiment. But the satiety part will be different. Since liver is one of the most nutrient dense foods you can eat, full of vitamins, minerals, essential fats and healthy fats, your cells won t be hungry. Their nutrient status will be high. This means they won t be hungry as in the previous experiment. It also means liver is good for satiety because when the experiment is over, you won t be ravaged; ready to eat just about anything. This is how satiety and satiation can be the same thing. What effects satiation? In both experiments, satiation quickly rose to high levels. In one, Twinkies and Pepsi, we were not sated. We were hungry, but tired of the food options. In the liver and water experiment, we were both sated and satiated. We weren t hungry, just tired of the food options. This leads to high levels of satiety and high levels of satiation.

5 More clear than mud? This means satiation is sometimes dependent on satiety and sometimes not, and it varies by nutrient density. (In other words, satiation is ALWAYS influenced by satiety because the very definition of satiety is based on NUTRIENT DENSITY.) Consider when satiation is low and we go grocery shopping. The smell of bread, donuts and the rest in the bakery department is VERY wanting. Grocery stores know this, which is why they try to funnel you through this area on every visit. The sense of smell influences us. Who doesn t like the smell of baking bread? Well, if your satiety is low, guess what? You are really going to want some bread, preferably fresh. This is the anticipation part. We can imagine how good a cinnamon roll or donut tastes by the smell alone. And it s hard to leave the store without them. But if we go to the grocery store when satiation is high, threats from the bakery department are low. Because we are satiated, we have little to no desire for them. And if there is some desire, it s not strong enough to compel us into making a bad decision. The last part of the previous sentence is key to understanding the difference between satiety and satiation. Satiation is something we can exert some control over. Satiety is not. No matter how much we do or do not want another Twinkie or Pepsi, we are not sated. Closer to Putting it all Together Let s summarize what we know about hunger up to this point. First, we have the terms like and want, which are distinct. Liking a food does not mean we will always want that food. Then we have satiety and satiation. Satiety indicates the status of nutrient absorption from our digestive system how hungry our cells are. When the status of nutrient absorption is high, our satiety is high. Satiation, on the other hand, is a desire eat more food, which could be high or low. Satiation is also something we can exert some mental control over, depending on the extent of our satiety. See Table 1.

6 Table 1. Defining Terms: Like, Want, Satiety and Satiation Terms Definition Willpower Like Want Satiety Satiation A food we have a desire to eat because of some level of pleasurable anticipation. A state indicating our desire to acquire a food. A state indicating the level to which our body has absorbed nutrients. A state indicating our desire to continue or stop eating. N Y/N N Y/N Table 1 contains basic definitions of terms we ve covered to this point. There is also a Willpower column, indicating whether or not willpower has a role with the component regarding hunger. We see that liking and satiety are not something we can influence with willpower. Certainly, whether or not you like a food can change. It can even be context dependent. For example, some people like mushrooms, but don t like them raw. This is a preference rather than willpower. Satiety, on the other hand, is a state indicated by your body on the nutrient status of the cells. There is nothing your willpower can do about this. Wanting and satiation, on the other hand, have some willpower components. Our want of a food indicates our willingness to acquire it. If we really, really, really want some ice cream, we ll do almost anything to get it, regardless of our willpower to resist. However, if we only really want some ice cream, we may be able to fight the cravings with willpower for a little while, but not forever. This is why wanting gets a Yes and No. Satiation also received a Yes and No. Recall from our 30-day experiment, when we are completely satiated, we have no desire to eat more Twinkies or drink more Pepsi. When not satiated, consumption will continue. However, we can become satiated even when not sated. This means even though we are hungry, at least our cells are, we have no desire to eat another Twinkie or drink another Pepsi.

7 Finally: Putting it all Together It should be clear that hunger is both complex and confusing. But what can we do about it? Well, we can t eliminate it. So we must deal with it. The principles we ve discussed to this point give us some clues on how to deal with it. The first step is to fit our psychology together with our physiology. Here is one way to summarize what we have covered so far: The best place to start is satiety. For our body to be sated, we need to consume foods that feed it. Recall nutrient status, which means this refers to more than just counting calories. We can expand on our examples from earlier to further illustrate this and make the point again. Let s use eggs and Twinkies. Eggs are extremely nutrient dense: an excellent source of protein and essential fats; and several vitamins and minerals, choline, for example. Two, large-boiled eggs contain 155 calories, including 13 grams of protein, 10 grams of fat and 1 gram of carbohydrate in the form of sugar. A single Twinkie, on the other hand, has 150 calories, including 1 gram of protein; 5 grams of fat, and 27 grams of carbohydrate, 18 of which are sugar. There are no vitamins and minerals to speak of in a Twinkie. Calorically, the foods are nearly identical: 155 vs. 150, which means they would have the same points or count the same in any calorie counting program. In terms of satiety, however, they could not be more different. Proteins are a highly sating nutrient, which we will learn in the Protein Module. Eggs have Twinkies beat 13 to 1! Healthy fats are also sating. Eggs have the Twinkies beat 2 to 1, but it s much worse than that. The fat

8 content of eggs is healthy and nutrient dense, which makes it sating. The fats in Twinkies, on the other hand, are partially hydrogenated soybean oil. In terms of satiety, nutrient density is almost non-existent. In terms of health, a partially hydrogenated soybean oil is one of the worst things you can eat. So no contest on the fats, either. Finally, in terms of carbohydrates, Twinkies have eggs beat 18 to 1 in sugar content. Note: This last sentence is also an important concept in hunger, one we will discuss in more details in Module 3 Carbohydrates. When you put all of this together, it means eating Twinkies will not promote satiety. It will however, promote hunger. Since you re only eating calories and not feeding your body, you re going to get hungry again. Soon! Now think about what you typically eat. If you re eating mostly foods that have calories and lack nutrient density, are you surprised to learn you re eating a lot of calories and frequently hungry? You shouldn t be and this explains why some people can eat constantly, yet never be sated. No matter how much food they eat, they feel like they can t stop eating. A big reason is the foods they eat (think of Lay s potato chips, remember the jingle, Betcha can t eat just one ). They aren t nourishing the body, so they can t be sated and can only experience brief moments of satiation. In other words, they are almost always hungry. To minimize hunger, we MUST eat foods that have two qualities. We MUST like them and they MUST be nutrient dense. This leads to being sated, which leads to satiation, which means we won t be as hungry. Recall from the introduction, we ll still like these foods, we just won t want them when full.