You fall off your diet not because you are so weak, but because food is so strong.

Eating is so important for your survival that you have two separate yet overlapping systems to control hunger: the life and love and systems. The life system is feeling hungry so you’ll eat enough to replace the energy you use in daily life. The love system is feeling hungry because of the reward¾you eat because you want food.

Individual differences in either of these systems can make it hard for you to stay on a diet because they give food the power to make you eat. Your willpower is strong. Your diet is strong. But if you are prone to obesity, food is strong enough that, over time, becoming overweight is almost certain without dramatic changes in how you stay on your diet.

Why Is Food So Strong? Survival.

Why is food such an overwhelming force for those prone to obesity? Survival. And how does your body get you to eat? It makes you hungry. Hunger is the big stick your body has to control your weight. Remember in The Power of Starvation Threat how the men in the experiment became obsessed with food? That’s simply a more extreme version of our normal urge to eat. And as we learned in The Power of Genetics Threat, a large number of genes interact to control obesity and we all have different genes, so we all have our own unique way of being overweight.

Almost all the genetic syndromes that clearly and obviously cause obesity work by making people hungry. Remember the story about the cousins who could not produce leptin? They were voraciously hungry nearly all the time. Those prone to obesity may simply have a greater basic drive to eat, depending on their own genetic makeup.

Why can you taste food at all?

A few simple-sounding questions helped connect the dots between food, eating, and weight: Why do you have a sense of taste at all? And why do you crave ice cream but you don’t crave cardboard?

So you can survive! Survival is the obvious reason behind why you eat, but it’s easy to forget.

Your brain doesn’t keep a big mental dictionary of the foods you should eat. You aren’t born with a picture of an apple in your mind and a drive to eat apples. How would you survive in a world without apples if this is how your body really worked? How would you learn about new foods when you entered a new environment?

Instead, your body has developed a more general and far more clever way of making you eat the foods you need to survive. It gave you the ability to taste fat, sugar, protein and salt because they are all flavors in the foods you need to survive.

What happens when you tastes these flavors? Do you feel pleasure? I certainly do. Why should you feel any pleasure at all from tasting food? If you were a computer, you wouldn’t feel pleasure, but you’re not a computer. Pleasure is how your body tells you that what  you’re doing is good and that you should do more of it. Pleasure is your reward for doing what your brain thinks will help you survive. Rewards are the way Mother Nature ensures you will perform the behaviors indespensible to your survival.

You seek out food because you can taste it. Tasting food gives you pleasure. Pleasure is your reward for eating food.  And as result of this innocent series of steps, you naturally eat a wide enough variety of foods that give you all calories and nutrients you need to survive. Pleasure seduces you into good behavior and Mother Nature always thinks that eating is good behavior.

It’s a pretty good system. Here’s how this system helped our anscestors survive.

To our ancestors, food with a sweet taste meant fruit because fruit would have been almost the only sweet flavor available to them. Why is eating fruit important? Because fruit is chocked full of vitamins and energy, both of which we need to survive. We love salt because we need salt for our cells to work properly. We love protein because protein is the most important building material for muscles and other cricial body functions. We taste sour and bitter flavors to warn us off bad foods. We love fat because fat has the highest number of calories and we need vast amounts of energy to survive. A 26 calorie chocolate kiss, for example, provides enough energy to lift a large SUV over six feet in the air!

The end result is, you’re attracted to these flavors. Food marketers and manufacturers know this. Do the ingredients of fat, sugar, and salt sound familiar? They should, because some combination of fat, sugar, and salt is in all junk food.

You love junk food precisely because it mimics the tastes your body is driven to love. But junk food is worthless as a food. It packs on pounds while providing next to zero nutrition. What a cruel trick to play on Mother Nature.

How Long Can You Hold Your Breath? Our Basic Drives are Strong

Jeffrey Friedman, a medical doctor and a famous researcher, illustrates the power of our basic drives with a wager. He says he will give someone $10 million if they can hold their breath for about one hour. Though everyone is extremely motivated to collect the reward, you know you can’t because your body will force you to breathe. Intuitively you know you can’t win the wager because you know your basic drive to breathe will win out over time and you will breathe. Can some people stop breathing until they pass out? I am sure there are such people, but there are very few who have the willpower necessary to overcome the drive to breathe.

What if the drive to eat is similar?

Drive to Eat About as Strong as the Drive to Drink When Thirsty

Friedman estimates the drive to eat isn’t quite as powerful as the drive to breathe, but he says the drive to eat after losing weight is about as strong as the drive to drink when you are thirsty. When I read that I was astonished. I just didn’t think of hunger and the drive to eat as being that strong. When you are thirsty, how long can you resist a tall glass of water? Not long. Yet on a diet, that’s the force you must be able to continually counter with your willpower. How possible do you think that is?

Is it reasonable to expect people to withstand such a strong drive to eat? As we’ll talk about in The Power of Slip-ups Threat, people really do an amazing job using their willpower to stay on a diet. The problem is you don’t need to slip-up very often to gain weight. And given the constant compulsion to eat it is unreasonable to expect people to rarely slip-up.

The Two Ways of Making Us Eat

Eating is so important for our survival that we have two separate yet overlapping systems to control hunger. I was quite surprised to learn we had two different mechanisms for making us eat. To the extent I had thought about it all, I had simply thought we ate to make up the energy we burned while going about our daily activities. But there’s a lot more to hunger and eating than simple energy balance.

Out with the Old Standard Model of Eating

My original idea of why we eat is what Michael Lowe, a professor of psychology at Drexel University, and Allen Levine, a professor of food science and nutrition at the University of Minnesota, call the standard model of hunger.

The standard model of hunger says there are two types of hunger: physical and psychological.

Physical hunger results from the need to replace the energy used in daily life by eating food. Physical hunger is part of what is called our homeostatic system, the natural system we have for maintaining weight. An important tool used in weight maintenance is the control of hunger.

Hunger exists to make you eat. Eating supplies energy and nutrition. Hunger is balanced by signals to the brain when you are full, so your brain will stop you from eating. A number of threats involve malfunctions in the homeostatic system. In the standard model, physical hunger is thought to be the only “real” form of hunger because it is motivated directly by your energy needs.

Researchers have learned quite a bit about the homeostatic system in recent years and there’s a mad dash to learn even more by those developing drugs to solve the obesity problem. The homeostatic system involves many important mechanisms, some of which we’ll see later in this book: insulin, leptin, neuropeptide Y, ghrelin, peptide YY, serotonin pathways, and many more.

Psychological hunger, in the standard model, isn’t thought to be real, because we aren’t eating when we are “truly” hungry. Instead, we are thought to be eating because we are sad or happy or for other non-physical reasons. Psychological hunger is eating based on emotion. The easy implication is that you should be able to control your emotions which will then control your eating. This is why you are thought to be weak if you can’t control your eating. The hunger isn’t real so you should be able to stop it. If you can’t stop your emotional eating then it must because of some weakness from within you. If you were just stronger and had more willpower then you wouldn’t get fat. I am sure you have heard this many times.

Most of us still think of the standard model as the way hunger works. But what if the standard model is wrong? What if your body had another way of making you eat? If that were true, would you still be weak and lack willpower for eating?

In with the Life and Love Model

Does psychological hunger really exist? The theory of psychological hunger may not be needed if a new hunger model proposed by Lowe and Levine, called the homeostatic-hedonic model, turns out to be true. Yes, homeostatic-hedonic is quite a catchy title, but they are scientists after all.

The homeostatic part is the same as physical hunger in the standard model. It’s eating because of need. This is what I call the “life” reason for eating. We eat to replace the energy we use to live. The hedonic part means eating for reward. We eat because want food. This is what I call the “love” reason for eating.

Why might we want food? One explanation some people will jump to right away is that we want food because we are pigs who can’t control ourselves. Let’s examine that a bit.

If I place a piece of cardboard in front of you, will you want to eat it? No. Why not? Because it’s not food. What you want is good tasting food. What defines good tasting food? That’s a surprisingly difficult question to answer. A good place to start is by asking what can you taste? Your taste buds can sense fat, sugar, and salt. That’s the kind of food you want. You want food made from fat, sugar, and salt. Why? Because that’s the kind of food you need to survive.

The food you want makes absolutely perfect sense from a survival point of view. You need to eat when food is available and your body needs a way to make you eat even if your immediate need-based food requirements have been satisfied. Any other approach would make you very vulnerable to famine.

The Better Food Tastes the More You Want to Eat

You may think it obvious, but it is well documented that people eat more the better food tastes. It’s not as obvious a statement as you might think. If hunger is only tied to your need to refill energy supplies, then the taste of food shouldn’t impact how much you eat. But the taste of a food at the start of a meal does predict how much you will eat. The better the taste the more you will eat. This is the “love” reason for eating.

What does this mean for those of us in the modern world where large portions of good tasting food are in near infinite supply?

This is our first link in the chain describing the Power of Food.

The Better Food Tastes the More You Eat, Even When You Are Full

When you are full, common sense would tell you your body should stop you from eating more. After all, you are full. You have all the energy you need for now, what’s the point in eating more?

Surprisingly, research shows that’s not how eating works. In fact, it’s just the opposite. Good tasting food makes you eat more, especially when you are already full! Good tasting, high energy food simply overwhelms the “I’m full” signal in your brain with a stronger “it’s time to eat” signal. You keep eating even if you previously felt full.

This makes perfect sense from a survival point of view. You have to eat when calories and nutrition are available; you can’t wait until later because later may never come.

What does this mean for those of us in the modern world where good tasting high energy food is in near infinite supply?

Add the second link in the Power of Food chain.

Seeing, Smelling and Even Talking About Food Makes You Hungry

Several studies have found the mere sight and smell of a food can make you hungry. Even talking about food can make you hungry! After all this talk of food, are you starting to feel a little hungry?

How do we explain getting hungry simply by seeing, smelling, or talking about food? Is it for homeostatic reasons? Nope, you aren’t hungry because you need more energy. The trigger is the presence of food you like.

The standard model of hunger would probably say you were experiencing psychological hunger, a hunger driven by emotional eating. But it’s not psychological, it’s physical and it’s in your brain.

Gene-Jack Wang, a physician at the Brookhaven National Laboratory, led a study using PET brain scanning techniques that discovered that the mere display or smell of one of your favorite foods causes the parts of your brain associated with the desire for food to light up like a Christmas tree. The study found new evidence that brain circuits involved in drug addiction are also activated by the desire for food.

“These results could explain the deleterious effects of constant exposure to food stimuli, such as advertising, candy machines, food channels, and food displays in stores,” says Wang. “The high sensitivity of this brain region to food stimuli, coupled with the huge number and variety of these stimuli in the environment, likely contributes to the epidemic of obesity in this country.”

The significance of this study is that the volunteers did not eat the food. Their hunger didn’t come from the pleasure derived from the eating of food. Mere exposure to food motivates your brain to eat in the same way addicts experience when craving drugs. Isn’t that interesting? Craving is your brain telling you something is important and you should pay attention.

From a survival point of view, becoming hungry when you are exposed to food you like makes perfect sense. You need to eat when food is available. The problem is in our modern world food is always available and the foods we like are usually high in fat and sugar.

Is your willpower strong enough to continually resist the hunger every time you see or smell food you like?

Some people tell me they don’t get hungry every time they see their favorite food so they don’t believe the results of these studies. It doesn’t have to be every time to have an impact on your diet. How about just sometimes? When I go into the bakery section of the store and I see and smell fresh donuts I am immediately hungry for them. Not every time, but enough of the time that if indulged on those times I would gain weight.

And what if everyone is not like you? What if some people have a much stronger attraction to certain foods than you have? Would you cut them some slack then? We’ll see in later sections how people can vary quite dramatically in their reaction to food.

Add another link in the Power of Food chain.

Overweight People Like Fatty Foods More

Many studies have shown the heavier a person is, the more they like fatty foods.

One study found that when compared to leaner people, heavier people who were fed high-fat foods ate more and reported greater feelings of pleasantness, satisfaction and tastiness from the high-fat foods.

Twin studies confirm that fatter twins also have higher preferences for fatty foods.

Now combine liking fatty foods with the finding that you’ll eat more of a food you like, even when you are full. What could be a worse scenario for becoming overweight?

Well, unfortunately, there is a worse scenario. Obese women have been shown to have a much greater preference for sweet high-fat foods than do lean women. Think chocolate. I bet many women you know passionately love chocolate. A preference for both sweet and fatty foods is the worst case scenario for becoming obese.

I think these findings are fascinating. I always assumed people loved foods pretty much equally. Again, I hadn’t given the issue much thought, but then I don’t think many of us do. We all eat. We all have a sense of taste. So why wouldn’t we all pretty much like the same foods equally?

It turns out we don’t like all foods equally. As we’ll cover throughout this book, we are all different and we all have individual quirks that set us apart from each other.

The conclusion is that a big reason some people become obese is because their body prefers fatty food. If your body preferred lettuce, for example, what would be your chances of becoming obese?

The downside of liking fatty foods is that fatty foods have the most calories. One tablespoon of butter, for example, has about 100 calories. Fat calories add up fast. If you eat a lot of fatty foods, there is almost no way you can exercise enough to burn off the excess calories.

When it comes to the choice of which foods you eat, isn’t it likely you will choose to eat the foods you like, more often than not? Even if your willpower is excellent, the preference for fatty and sweet foods operates on you every moment of every day of your entire life.

Is it reasonable to expect in our modern environment, offering endless access to sweet and fatty foods, that your willpower is perfect enough to prevent obesity?

Add another link in the Power of Food chain.

Your Biology Helps Determine Which Foods You Like Best

You may be thinking obese people like fatty and sweet foods for psychological reasons. You may be thinking that if these people were just right in the head they wouldn’t like fatty and sweet foods anymore. As attractive a theory as this may be to some, the preference for fatty and sweet foods has deep roots in your biology. The next several sections will show this.

Overweight People Get More Pleasure from Eating

If for some reason a person got more pleasure from eating than you did, would you expect them to naturally eat more? I would think so, yes.

In a fascinating research finding, scientists found overweight people get more pleasure from eating than do lean people.

Researcher Gene-Jack Wang at Brookhaven National Labs used a PET scan machine to compare the brain activity of obese and normal weight volunteers who had fasted to make themselves hungry.

Results from the study suggest that overweight and obese people may overeat because the parts of their brains that are stimulated by sensations in the mouth, lips and tongue are more active than in those at a healthy weight.

“This enhanced activity in brain regions involved with sensory processing of food could make obese people more sensitive to the rewarding properties of food, and could be one of the reasons they overeat,” Wang said

The brains of overweight people are set up to get more pleasure from food and eating. Obese people are very sensitive to the pleasurable sensations of food! And as we have seen, more pleasure means you’ll eat more and eating more leads to obesity.

This study found real physical reasons why overweight people like and consume the foods they do. It’s hard wired. Each person responds differently to the rewarding aspects of food.

Is it reasonable to expect people who get more pleasure from food to be able to counter the consequences for the rest of their life?

Research by Duke University psychologist Susan Schiffman has also shown that overweight people have heightened requirements for foods that are fatty, flavorful and highly textured. These exaggerated needs doom most diets because, she says, “When you cut back calories, you frequently cut out the fat. You also cut out a lot of the taste, smell and texture.” The trick is to add these qualities back into the food or you’ll find it hard to keep the weight off.

A lot of people may overeat because they get a big reward out of food. Some people play the lottery. Other people can get a big payoff simply by eating.

Add another link in the Power of Food chain.

Food Demands Your Attention

The ultimate power of food comes from recent research showing that for certain people, food is addictive. The addictiveness of food is a very controversial idea. Some don’t want food to be addictive because they think it gives others an excuse to eat whatever they want. Once food becomes addictive the thought is people can’t help it anymore and they are absolved of responsibility.

The addictiveness of food does not absolve anyone of responsibility, just like being more prone to nicotine, alcohol, or cocaine addiction doesn’t absolve those addicts of responsibility. We are all responsible for our actions. It’s just for some of us being predisposed to an addiction makes that responsibility much harder to live up to.

We have all been dealt a different hand. Character is how you deal with the hand you’ve been dealt.

But in the case of food, how can you deal with an addiction you don’t even know you can have? Most people still buy into the psychological theory of hunger, so most people won’t think they are addicted, they will think they are just weak.

In another study lead by Gene-Jack Wang , they found dopamine, a brain chemical associated with addiction to cocaine, alcohol, and other drugs, may also play an important role in obesity.

Dopamine is now thought by researchers like Dr. Nora Volkow, director of the National Institute on Drug Abuse, to tell us what we need to pay attention to in order to survive. New information is bombarding us all the time, what information should we think is important? Dopamine is released when something surprising and important happens.

What is important could be an unexpected reward like a cheese burger or a painful accident like placing your hand on a hot burner. With the help of dopamine, we are able to pay attention to the information we need to survive, act on the information, and remember the information later.

Given all that the dopamine system does, it’s impossible to think of surviving without it. But rarely is anything all good and dopamine’s downside can be found in drugs and addiction.

A drug like cocaine pumps five to ten times the normal amount of dopamine into your system. What do you think that does to you? It makes the drug the most important thing to pay attention to in your life. The drug effectively hijacks the system your body uses to regulate attention by turning all your attention back to the drug. If you have noticed addicts have a hard time thinking of anything but their drug, it’s because that’s exactly what is happening.

Addicts have been found to have fewer dopamine receptors in their brain. Receptors are the parts of your brain that sense the dopamine in your system. An analogy is a radio that tunes into a particular radio station. With fewer receptors, the dopamine signal is weak. If you heard a weak signal on your radio you would try to tune to a station with a stronger signal. But there’s no way to change the “dopamine” station. What you have to do is make the dopamine signal stronger by upping the power.

How does an addict boost their signal? They take more and more of the drug. An addict needs to take more of the drug to feel anything at all.

’Even scarier, because your brain is paying most of its attention to the drug your prefrontal cortex stops functioning normally. Your prefrontal cortex is the part of your brain responsible for judgment and stopping you from doing things you shouldn’t do. It’s in charge of doing the harder thing. With an impaired prefrontal cortex, your judgment is worse and you are more likely to engage in risky behaviors.

What we then have is a combination if extreme motivation for a drug and a reduction of the ability to stop taking it. That’s one reason addiction is so difficult to defeat.

What has all this got to do with obesity?

People are born with different numbers of dopamine receptors. Obese people were found to have fewer dopamine receptors than people at a normal weight. In fact, the more obese a person was, the fewer dopamine receptors they had.

Oh boy. All the drug addiction problems we talked about with a drug like cocaine apply to food as well, but with one important difference: food isn’t nearly as strong as a drug as cocaine.

There’s evidence, however, that a high calorie meal made up of fat and sugar can approach the strength of a drug in the release of dopamine. Hmm, a high calorie food made out of fat and sugar, does that sound like fast food and junk food to you? So the addiction may not be as powerful, but it seems powerful enough to lead to obesity.

Why does having a lower number of dopamine receptors lead to addiction? At first I thought having a higher number of receptors would lead to addiction. My reasoning was if you had a higher number of receptors then you would get more pleasure from food so you would want it all the more.

I was wrong. Having a lot of receptors means you are very sensitive, so a little goes a long way. Too much and you don’t like it.

I think of it like loud music and someone who is hard of hearing. If you are hard of hearing, you have to turn up the volume really loud so you can hear the music. If your hearing is excellent, then loud music hurts your ears and you will immediately plug your ears with anything handy to escape the loud sounds crashing into you.

Eating food while having more dopamine receptors is like listening to loud music with excellent hearing. You won’t be able to handle the over-stimulation of eating more and more food if you have a lot of dopamine receptors, so you will stop eating sooner. This is how thinner people react¾they stop eating, the stimulation becomes too much.

But if you have fewer dopamine receptors, then you want to keep enjoying the pleasure of food, so you keep on eating. This how people prone to obesity react to the rewarding properties of food, they keep on eating.

If you have fewer dopamine receptors, you are not eating to get high; you are eating to feel normal. You need to keep on eating to keep feeling pleasure so you can feel good, so you can feel well, so can feel like a normal person.

The fewer receptors you have, the more you will have to eat to feel something. That’s probably why the heaviest people had the fewest receptors. The heavier people need to eat more to trigger their dopamine system. Why food? Heavier people have been found to have bodies that extract more pleasure out of food than thinner people so food is a very convenient and practical drug.

Interestingly, mice bred without dopamine receptors quickly starve themselves to death. Goldilocks wanted her porridge just right, not too hot or too cold. That’s how we need our dopamine receptors too, not too many or too few. The number of receptors you have is determined by the genetic lottery that was held when you were born. The results of this lottery heavily influence your fate.

But like almost all the topics we’ll talk about in this book, it’s not all a lottery. You are still the biggest influence in your own destiny, even if it doesn’t feel that way sometimes.

Exercise, of course, has been found to increase the number of dopamine receptors. Why is the answer always more exercise? But, exercise is just one of the things you can do to change the lottery results. The strategies in this book give a lot of other things you can do too.

More Evidence for Food Addiction

In yet another study, Gene-Jack Wang and his team found obese people may be as addicted to the drug of food as junkies are to other drugs. The study monitored the brains of test subjects who had a device implanted in their stomachs, allowing researchers to trick their brains into feeling full.

They found that the brain circuits motivating obese people to overeat are the same that cause addicted people to crave drugs. These circuits are also linked to eating to soothe negative emotions.

The implications of the study are that even if you lose weight you will still feel food cravings that you can’t suppress. This adds up to a high chance of relapse—that means regaining your weight back.

Believe it. Food has all the power it needs to get you to eat.

Changing How We View Obesity

For the longest time, society thought drug addicts were simply morally weak people who couldn’t deal with life. Now many people think of addiction as a medical problem. There has been a similar change of heart on depression. Depression was also once thought to be a weakness of character. Now depression is often diagnosed as a problem of brain chemistry and may be treatable using drugs.

There is still research needed to establish the relationship between food and addiction, but it’s clear to me that over time we will change our view of obesity to be more like how we now think of depression and drug addiction. What motivates us to eat is clearly much more complicated and powerful than the outdated psychological model of hunger that is now the default view of obesity.

Add another link in the power of food chain.

Why do people become addicted to food and not other drugs?

People who have a hard time thinking of food as an addictive substance often ask this question. Here are two possible answers:

1      People attracted to food also become addicted to other drugs. A big problem for many people who have lost weight is that they move on to become addicted to other drugs. It’s not an either/or situation.

2      A more interesting answer is to remember that people prone to obesity often feel more pleasure from food than people not prone to obesity. Their brains are particularly sensitive to food. So, for them food is a very attractive drug. They really don’t need to find another drug. And when you consider that food is legal, relatively cheap, endlessly varied, socially acceptable, and in great supply, why would you need another drug?

The Power of Food Chain Is Strong

In this threat I have added a lot of links to the Power of Food chain. Link by link I’ve tried to show how food itself has the natural power to make us hungry and eat. You don’t need to make up psychological reasons for why you eat. Tasty high-fat and high-sugar foods are all the reason you need to eat because that’s the kind of food that helped humans survive in the past.

Now add that many people, for genetic reasons, are more prone to obesity because they are physically more vulnerable to wanting good tasting food.

Now add to that the 24 hour a day availability of and exposure to high calorie good tasting food.

The real question that comes to mind is: how is anyone not overweight?

The common treatment for drug addiction is to stay completely away from the drug you are addicted to. Drugs are so strong a single exposure can cause a relapse. Food addiction is so hard because you can’t stay away from food. You must eat to survive.

Given the extreme Power of Food isn’t losing weight and staying on a diet hopeless? It’s not easy, but it’s far from hopeless. You can’t just break one link in the chain and solve all your problems. All the links must be attacked simultaneously.

By understanding the true power of food, you become capable of devising strategies to beat its power. Many of the strategies that follow are directly targeted at defeating the power of food.