In a nation where obesity and health loom large in our public dialog, there is no escaping the simple fact that we eat too much.

On average Americans consume 500 more calories per day than we did in 1970 (more than we ever have), mostly in the form of refined and processed foods. This corresponds with a 25-30 pound increase in body weight and obesity rates near 30%.

Debates rage over the specifics of what is causing our weight and health problems, but it seems clear enough that the critical element is the amount of food we choose to put in our mouths.

But does everything we eat represent a true choice?

In his book The End of Overeating, former FDA commissioner Dr. David Kessler examines the role of the brain in eating behavior and the mechanisms involved in what he calls conditioned hypereating.

According to his findings specific combinations of sugar, fat and salt hijack the reward pathways of our brain and force us to behave more like food addicts than hungry organisms. This leads to a cycle of conditioned hypereating that makes the habit harder to break with each repeated episode.

But whether or not we are addicted to food is a point of debate. In my interview with Kessler, he made clear he does not use the word addiction for fear of oversimplifying conditioned hypereating. Our relationship with food is more complicated than it is with something like alcohol or tobacco because a human can live without cigarettes, but food is vital to survival.

When pressed to describe the neural differences between addiction and conditioned hypereating, however, Kessler conceded, “The fundamental circuits are the same.”

For this reason, treatment of conditioned hypereating can draw from the success of substance abuse treatments. These tactics involve cognitive and behavioral therapies we can use to train ourselves to override our instincts and adopt new behaviors in response to stimulus cues.

For conditioned and compulsive behavior, cognitive strategies are necessary because intuitive inclinations and “listening to your body” do more harm than good. If your body is telling you to have a cigarette, this does not mean it is in your best interest to do so.

At the FDA Kessler was instrumental in the fight to regulate tobacco, and now he believes some of the same lessons can be applied to the treatment of overeating.

“What took me a decade to understand is you need to change the valence of the stimulus.”

The positive emotional reaction associated with indulgent foods is at the center of our motivation to seek them out. Twenty years ago cigarettes had tremendous allure. But the FDA was successful at demonizing the tobacco industry, and the public no longer sees smoking as glamorous and attractive.

And smoking rates have plummeted.

Changing a conditioned behavior requires a fundamental shift in how we think about a stimulus. In conditioned hypereating the stimulus is food, which makes the task especially difficult, but not impossible.

To break the cycle of conditioned hypereating we must redirect our automatic response to the kinds of foods that cause us to overeat. Kessler calls these hyperpalatable foods, which are loaded with layers upon layers of sugar, fat and salt. The goal is to replace our automatic responses to these foods with different, equally enjoyable actions that are not detrimental to our health and do not reinforce compulsive behavior.

I asked Kessler what is the first step in controlling our eating habits and overcoming conditioned hypereating.

“I can tell you the last step. Change your relationship with food. If sugar, fat and salt are your friends, you will lose. You have to get to the point where that is not what you want.”

The End of Overeating outlines the four basic steps of habit reversal: awareness, competing actions, competing thoughts and support.

But Kessler believes the critical step is fundamentally changing the way we view what we eat, cooling down our emotional response to hyperpalatable foods. In essence, we must train ourselves to stop wanting what we believe we want.

According to the book, the first step in this transformation is becoming aware of the power food holds over us, which requires understanding how our brains work. We must recognize that when we are tempted to indulge, the urge is not generated internally but is a reaction to a cue that makes us respond automatically. You may think you are hungry, but really you are just reacting to an emotionally charged stimulus that tells you to eat.

Once you recognize a cue for what it is you have a brief moment to decide not to take the bait. To successfully divert yourself to another course of action you must have a plan ready in advance that allows you to do something completely different.

Considering alternative activities and the reasons you might prefer them can help you tremendously at this point of decision. Rather than focusing on the positive emotions you will experience by giving in to your desire for hyperpalatable foods, also remember the negative emotions that follow if you give in and the positive aspects of the alternative action.

For instance, it may help to remember that every time you get cued and give in, you are strengthening the neural circuitry that compels you to this behavior in the first place. If you even briefly entertain the possibility of indulging, you create a state of ambivalence that leads to torment, obsession and cravings. However, when you successfully divert your attention to another rewarding activity you have made a small step toward cooling down the positive valence of the food.

It is the state of mental torment and ambivalence that increases the positive emotional charge of a food, building and strengthening the neural reward circuitry that causes conditioned overeating. This may be one of the reasons dieting almost always results in long-term weight gain, since constant deprivation makes hyperpalatable foods more difficult to resist and creates severe anxiety.

Mentally, the best strategy to overcome conditioned hypereating is to develop new, positive associations with food that are independent of palatability–something you care more about than the fleeting reward of overeating. Kessler says this is a deeply personal process and must reflect an individual’s own set of values. For example, it helps some people to become vegetarian, while others value organics or local food. These decisions remove virtually all hyperpalatable food from the lives of people who choose these paths.

It also helps to develop aversions to hyperpalatable foods. Some may learn to demonize “Big Food,” while others turn away after educating themselves about health concerns. Developing a more sophisticated culinary palate can help make hyperpalatable foods less palatable. Kessler himself developed an aversion to over-sized portions, which he now sees as repulsive piles of sugar, fat and salt.

Developing positive associations with healthier foods while demonizing the hyperpalatable foods we have been conditioned to crave can fundamentally change your emotional response to stimulus cues. As you learn to recognize your brain’s response to cues, you can override conditioned behavior by consciously deciding to take alternative actions because you want to.

You will never win an internal battle with yourself. Instead use what you know about the brain’s reward system and give up trying to summon willpower to resolve the torment of conflicting desires. Reprogram your habits by closely examining your relationship with hyperpalatable food and begin making deliberate decisions that are consistent with your goals, breaking the cycle of conditioned overeating.

To read more about conditioned hypereating and habit reversal read The End of Overeating, by Dr. David Kessler.

Have you read The End of Overeating? Have you overcome conditioned hypereating?

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In the first official book review at Summer Tomato I examine Dr. Colin Campbell’s The China Study. Several readers have asked about this book since I wrote last week about who you can trust for diet advice, so I think it is a perfect subject for my first review.

The China Study was published in 2006 and branded itself as “The most comprehensive study of nutrition ever conducted.” It is written by Colin Campbell, PhD, a highly accomplished scientist that has worked for decades in the fields of nutrition and disease research. It was co-authored by his own son, Thomas Campbell.

Clearly both these men care deeply about health and nutrition and believe the information they provide can relieve a huge proportion of the world’s suffering. Their sincerity is apparent and, given the current dietary trends in Western culture, I am sure their recommendations would help the vast majority of people become healthier. Yet there are several logical flaws in The China Study that prevent me from giving it an A grade. Overall, however, The China Study offers a compelling view of nutrition and health from one of the leaders in the field and is worth reading.

My biggest disappointment with The China Study is how little of the book is devoted to the study itself–a large ecological-style research project, conducted by Dr. Campbell and his colleagues, examining the relationship between diet and health in rural China. As a scientist, I am a bit of a data junkie and always most impressed by strong statistics and rigorous logic.

UPDATE: [Denis Minger has taken it upon herself to re-analyzed the data from The China Study, and makes it pretty clear that Campbell vastly overstates his case. I agree with everything Denise writes, and every educated person who cares about these findings should read her analysis.]

Only a single chapter in the book is specifically dedicated to the work done in China (Chapter 4), and it conveys little new information. Most of Chapter 4 is spent reiterating the links between diet and chronic diseases such as cancer, heart disease and diabetes, discoveries that did not surprise me in the least. The two most important novel findings reported in the China study are discussed below.

The China Study is divided into four major sections. The first section describes Dr. Campbell’s original research and is the part I enjoyed most. It begins by discussing his work in the Philippines where he discovered a tight link between animal protein consumption and a specific kind of liver cancer induced by aflatoxin, a dangerous poison that is sometimes found in contaminated peanuts. He follows up this work with extensive studies in his U.S. laboratory elucidating the mechanisms of cancer promotion by the main protein found in cow’s milk, casein. Dr. Campbell makes a compelling case that this protein can influence cancer development in the presence of an extremely potent carcinogen, and his work should be taken very seriously in this regard. However,  he goes on to argue that this finding can be generalized to support the view that all animal proteins promote cancer and he recommends they be completely eliminated from your diet.

This was a logical leap I was not able to make after reading through his evidence. What about the benefits of fish for the heart and brain?

As mentioned above, the final chapter of the first section describes the China study. According to the book, the Chinese consume much less fat and protein than Americans, but more fiber and iron. Nothing too surprising there. It also reports that rural Chinese have substantially less heart disease, cancer and diabetes than Americans, but in more urban areas where diets follow more Western patterns the incidences of these diseases are higher. Again, not surprising.

Two pieces of information out of the China study did pique my interest. The first is that participants in the China study reportedly consume more, not fewer calories than Westerners. This was true even for Chinese office workers who consume 30% more calories but weigh 20% less than average Americans.

Part of this difference was accounted for by differences in physical activity (even office workers in China get more exercise than we do), but not all of it. Data in the China study suggests that Chinese have a more active metabolism and burn more calories than typical Americans. Dr. Campbell argues that this is because they eat less animal protein and fat, but the China study is observational (non-intervention) and cannot prove cause and effect.

Isn’t it possible that the Chinese metabolize their food differently because it is less processed than Western food (no matter the source)? From the literature I have read, this seems like a more plausible explanation. But regardless of the reason, the data from China suggests that all calories are not created equal in terms of both health and metabolism. This argues against the dogma offered by most nutrition experts that a calorie is a calorie.

The other surprising finding from the China study is the degree to which blood cholesterol levels predict heart disease. Although most Americans assume there is some connection between blood cholesterol and heart disease, there is still debate regarding how strong this connection is. Data from the China study suggests lower total cholesterol levels decrease risk of heart disease and death. Moreover, the data suggests that optimal cholesterol levels are far below what are recommended by Western medicine (150 mg/dL to 180 mg/dL). The healthiest Chinese had total cholesterol levels from 170 mg/dL to as low as 90 mg/dL. In the China study, lower cholesterol levels were also linked to decreased rates of several cancers. However, some scientists question the validity of this data.

The second section of the book is titled “Diseases of Affluence” and discusses the role of nutrition in the various chronic diseases that plague Western culture. In the third section Dr. Campbell offers his ideal (i.e. vegan) diet. If you are not familiar with the literature on diet and nutrition Dr. Campbell does a decent job going over it, particularly with respect to the role of dairy in prostate cancer, type 1 diabetes and multiple sclerosis. However, most of this information is available in other books that are easier to follow and less dogmatic about the need to eliminate all animal protein from the diet, which even Dr. Campbell admits “has not been absolutely proven” (p. 242).

In my opinion the most incongruous part of The China Study is the fourth section titled, “Why Haven’t You Heard This Before?” Here Dr. Campbell goes into great detail explaining the ties between food industries, drug companies, our government and, sadly, our education system from K1 through post graduate medical residency. While this section of The China Study is fascinating, it dilutes the primary nutrition message of the book with a disconcerting illustration of the roles money and politics play in our education system. But despite the jumbled message, the facts provided in this final section of The China Study are eye-opening and may be the best reason to read the book. It is shocking to learn how deeply opposed to and uneducated most of the medical community is about the life-saving benefits of dietary intervention for chronic diseases. Personally I would have liked this section to be an entirely separate book, as I would recommend it more often.

To summarize, The China Study provides an interesting but not entirely compelling argument for adopting a vegan diet. It also offers a hefty dose of skepticism about who you can trust for nutrition advice, particularly when it comes to the medical community. Overall I enjoyed reading the book and, despite my criticisms, agree with most of it. I have no doubt that for the vast majority of Americans Dr. Campbell’s advice and recommendations would be immensely beneficial.

Final Grade: B

Please add your thoughts on The China Study in the comments below.

Know anyone who is trying build healthy habits? Want to give yourself a leg up on your New Year’s resolution? Here are some simple gift ideas for anyone wanting to embrace a healthy lifestyle:

1. Eat, Drink and Be Healthy, by Walter Willett. This is my favorite nutrition book. Dr. Willett, a physician and Harvard nutrition scientist, presents a comprehensive guide explaining the basics of nutrition science and why few things are as important as what you choose to eat. His recommendations are based on solid science, but everything is explained in clear, simple language and is easy for anyone to understand. This book will change the way you think about food and nutrition.
2. Subscription to Cooks Illustrated magazine. It is almost impossible to have a healthy diet if you are eating out for most of your meals. Cooking at home can be a pleasure, but to many people it is a source of fear and anxiety. Cooks Illustrated is a resource that demystifies cooking and makes it virtually idiot proof. Their staff tests recipes over and over in “America’s Test Kitchen” so you don’t have to. The result is the easiest, most reliable method for making almost any meal.A bonus of subscribing is that they also offer product and appliance reviews. I often find myself browsing their website with my online subscription, but they also have a beautiful print magazine if you prefer to peruse recipes on the go. Because of Cooks Illustrated I feel like I can cook just about anything I set my mind to, even things I have never tasted before. I couldn’t live without my Cooks!
3. Braun Hand Blender. This is the magic kitchen appliance. If you or someone you know is not the type to buy every single piece of fancy kitchen equipment, this is the perfect item. Its many attachments make it so you have a blender, food processor and mixer all in the palm of your hand. Everything you need rolled into one tiny device!
4. CSA membership. Busy people have trouble finding the time to buy fresh fruits and vegetables every week. CSA, or Community Supported Agriculture brings fresh, seasonal produce to you. The idea behind a CSA is that you subscribe to a farm or collection of farms and pay a certain set price (varies by farm) for a box of their goods. For your fee you will be provided with a week or two worth of fruits and vegetables of the season. All CSAs are a little different, so you need to find ones in your area and contact them to work out the details. Most deliver to your house or a nearby pick up point and allow some filtering for your particular food preferences. For the truly dedicated, there are also meat and dairy CSAs.
5. In Defense of Food, by Michael Pollan. Michael Pollan is a journalist and UC Berkeley professor who has spent the past several years figuring out the best way to eat in the Western world. This book distills everything he found, and his advice is surprisingly simple: Eat food. Mostly plants. Not too much. In Defense of Food is a quick, easy read that is both entertaining and filled with valuable information.
6. Wii Fit. I’m not sure if a video game can really be exercise, but it sure beats sitting on your butt watching T.V. I cannot deny that on cold evenings when I have worked too long at home to squeeze in a workout I have resorted to my Wii to get the blood pumping. Wiis are not easy to acquire (I have had success with Wii Alerts), but if you can get your hands on one they are easily worth the money.
7. Pressure cooker. You probably do not eat enough legumes. People have weird ideas about beans and assume they are accompanied by foul smells, but home-cooked beans are an entirely different species. A pressure cooker can make it so you have a week’s supply of your favorite beans in under half an hour. What’s not to love?
8. Full body massage. The latest research suggests that stress may be as bad for you as red meat. Luckily getting rid of stress can be one of the best experiences of your life. Everyone loves a trip to the day spa. A full body massage is the perfect gift for that person who has everything.
9. Lunch box. Eating out for lunch every single day is not an option if you want to be healthy. But that does not mean you have to be a nerd. REI makes a great, affordable lunch cooler that is both stylish and functional. Want more of a selection? Browse the offerings at Amazon.com through the link on the sidebar.
10. Email subscription to Summer Tomato. It’s free and comes with a 25-page healthy eating guide! Get to know what fruits and vegetables are in season, learn about the latest nutrition research and discover simple and delicious recipes for health straight from my brain to yours. This is the ultimate gift for the ultimate connoisseur! (OK, I admit this is kind of a cheap gift. I recommend it, but you should probably get one of those real gifts I mentioned too 😉

Good luck shopping and happy holidays!

Check out my 2009 healthy gift ideas