close up of hand adjusting scale

Over the years, researchers have uncovered many factors that can increase a person’s risk for developing or dying from cancer. Many of these factors are controllable – meaning there are things people can do to lower their cancer risk.

Here are some examples of research discoveries that led to some of the most important ways known today to help prevent cancer:

DISCOVERY: Smoking can cause cancer
PREVENTION STRATEGY: Stay away from tobacco products

DISCOVERY: UV radiation can cause skin cancer
PREVENTION STRATEGY: Limit exposure to UV rays by covering up, wearing sunscreen, a hat, and sunglasses

DISCOVERY: Poor diet can increase cancer risk
PREVENTION STRATEGY: Eat a healthy diet, with lots of plant foods

DISCOVERY: Physical inactivity can increase cancer risk
PREVENTION STRATEGY: Exercise regularly and limit sedentary behavior

DISCOVERY: Obesity can increase cancer risk
PREVENTION STRATEGY: Be as lean as possible throughout life

DISCOVERY: Alcoholic beverages can increase cancer risk
PREVENTION STRATEGY: For those who drink, limit consumption

Making the discovery is just part of the process though. For this knowledge to have an impact, all people need to actually do the things that can help prevent cancer – and this is not the case currently.

For instance, cancers caused by tobacco use could be prevented if everyone stayed away from tobacco. Many skin cancers could be prevented by following skin protection recommendations. In addition, about half of all cancers globally could be avoided if current cancer prevention strategies are more fully implemented, according to the World Health Organization's International Agency for Research on Cancer (IARC) .

Yet as anyone who has tried to quit smoking or lose weight knows, doing what they know is good for them can be difficult. Here, a roundtable of experts from the American Cancer Society’s Behavioral Research Center and Cancer Control department discuss what current research shows in terms of why it is so hard for people to change their habits – even when it comes to helping prevent cancer.

The expert roundtable:

Kassandra Alcaraz 150x150Kassandra Alcaraz, Ph.D., director of health disparities research, conducts original research to better understand populations with a disproportionately high cancer burden.




Kevin Stein 150x150Kevin Stein, Ph.D., managing director of the Behavioral Research Center, researches the factors related to the physical and psychosocial functioning of people affected by cancer.




 Lee Westmaas 150x150Lee Westmaas, Ph.D., director of tobacco control research, focuses his research on factors that individually and interactively influence smokers’ motivation to quit and their success in quitting.




Colleen Doyle 150x150Colleen Doyle, MS, RD, director of nutrition and physical activity, develops strategies to increase awareness of the importance of diet and exercise for chronic disease prevention and management.




Q. Studies have shown that Americans whose lifestyle conformed to the American Cancer Society’s Guidelines for Nutrition and Physical Activity for Cancer Prevention were much less likely to die from cancer. These guidelines include the broad recommendations to maintain a healthy weight, be physically active, eat a healthy diet, and limit alcohol intake. However, even though this information has been known for a long time, the obesity rate in the United States remains high and many Americans are not getting nearly enough exercise. Why is it so hard for Americans to change their behaviors?

Alcaraz: While guidelines and other types of information are critical to educate people about healthy behavior, they are only one part of the equation. Humans are complex, and the way we behave is influenced by multiple, interconnected factors. These factors include a person’s own thoughts and perceptions, friends and family, work or school environment, community, and health and social policies. All of these factors can make it more or less difficult for people to engage in healthy behaviors.

Another reason behavioral change is difficult is because there is no “one-size-fits-all” approach that will work for everyone. Some people might be motivated to make changes in their behavior if they are diagnosed with a health condition or lose a loved one to a disease. Others might change because people around them have decided to change or because their doctor advises them to.

Preventive health may be a relatively low priority for others, such as individuals living in demanding socioeconomic conditions. If you’re trying to keep a roof over your head or can barely get enough food to eat every day, preventive health behavior probably isn’t at the forefront of your mind. So those basic human needs must be met before focusing on health behavior.

Also, many people actually know that certain behaviors are unhealthy but just don’t know how to adopt healthier behaviors in their own lives. In our health behavior research, we continue to try to understand the complexities of health behavior and behavioral change so we can identify what works to help people be healthier.

Doyle: This is a perfect example of knowledge alone not being enough to make lasting lifestyle changes. Changing behavior is very difficult, and this is particularly true from an eating and exercise perspective, because there are so many things working against us:

  • increased availability of food and beverages;
  • increasing portion sizes – both at home and when eating out;
  • extensive advertising and marketing of foods and beverages of low nutritional value;
  • longer workdays, with less time for preparing meals at home (which tend to be lower in calories and more nutritious than restaurant meals) and for exercising;
  • and communities that are designed in ways that limit the ability to safely walk or bike to get to work or to school or to the store; and more.

Knowledge and will power are not enough to overcome these issues that influence our eating and exercise behaviors. That’s why our guidelines go beyond letting individuals know what they can do to reduce their cancer risk; they also address what communities can do so that it is easier for people to make healthier choices.

Q. The U.S. Food and Drug Administration (FDA) recently proposed changing the look and contents of the nutrition labels that appear on packaged foods. The proposed new labels would have the calorie count in a larger font size and would update serving size information to better reflect the portion sizes Americans actually eat. Do you think changes like this will help people make better food choices?

Doyle: It’s interesting to note that this is the first significant update to the Nutrition Facts label that the FDA has proposed since 1993 – when these labels were first required to be included on most packaged foods, beverages and supplements. This new emphasis on calories and a revision of some foods’ serving sizes is appropriate and welcomed, given the rates of overweight and obesity in the country.

Calorie content in the past has been based on what has been classified as a “standard serving size,” but we know the portions that people typically eat are larger than this. Giving consumers a more realistic idea of the number of calories that they are actually consuming when they serve up a portion is an important piece of the puzzle in making healthier choices.

Also welcomed is the first-time proposal to add a new line on the panel for “added sugars.” Currently, these sugars and sugars that occur naturally in foods are combined into a single line of “total sugars.” This will help consumers know just how much sugar has been added to what they are consuming.

Time will tell the extent to which these new labels actually do help people make better choices. Changes such as these would complement other nutrition labeling strategies – including the menu and vending machine calorie labeling requirements in the Affordable Care Act – all of which are important for creating an environment that better supports consumers’ ability to make healthier food and beverage choices.

Q. In your research, have you found that there are specific strategies that help people to be more successful in improving their health behaviors?

Alcaraz: Yes, we have learned quite a bit through research. For example, we know that behavioral change is a process, not a one-time event. This is why some people are not successful the first time they try to change their behavior but ultimately do so after repeated attempts. They are moving through this process and increasing their ability to change along the way.

We know that people must be ready to change; otherwise the change is unlikely to be sustained over time. There are ways to assess people’s readiness to change and strategies that can help them move through the process of change depending on how ready they are.

We also know that people must believe they can be successful in changing their behavior. We call this self-efficacy, and this can be assessed as well. For example, if an individual has low self-efficacy for eating healthier, we should combine strategies to increase self-efficacy with strategies to change eating habits.

A general strategy that can support positive health behavior change is ensuring all people have access to resources that facilitate a healthy lifestyle. Unfortunately, inequitable access to healthy food, environments that facilitate an active lifestyle, and quality preventive health care information and services make it difficult for everyone to improve their health behavior. Strategies that address these inequalities are promising, as they may have the greatest impact on long-term behavioral change at the national level.

Lastly, we know that the easier we make it for people to engage in healthy behaviors, the better. This is why policy-focused strategies and those that address people’s social and physical environments are so critical.

Q. Staying away from tobacco is one of the most well-known strategies for helping prevent cancer. While the smoking rate has come down significantly over time, millions of American adults still smoke cigarettes. What are the challenges when it comes to smoking in particular that make it hard for people to quit and stick to it, or never start in the first place?

Westmaas: Quitting can be difficult for many people because tobacco smoking is highly addictive, especially for daily smokers who have smoked heavily for a number of years. Over time, changes to cigarettes have made them more addictive, and for someone who has been smoking heavily a number of years, there are many psychological and biological factors that converge to make it difficult to quit.

For many it’s a well-ingrained habit that’s associated with certain activities (e.g., the cigarette after breakfast, or on the drive to work), or with certain triggers (e.g., feeling stressed, seeing other people smoking).

Also, the withdrawal symptoms can be unbearable for some people; these include feeling anxious, depressed, and unable to concentrate. These all make it easier for a would-be quitter to relapse. This is why medications for quitting are important in helping someone stop smoking – they help to reduce the intensity of withdrawal symptoms if used appropriately.

Environmental factors are important too. If smoking is restricted in a lot of places, and the price of cigarettes is high, then a smoker is likely to be more motivated to quit and to seriously seek help for quitting, which can make it easier to quit.

Having laws in place to restrict smoking, the sale of cigarettes to minors, and the glamorous depiction of smoking in movies, as well as making the price of cigarettes high, lead to a de-normalization of smoking, which reduces the likelihood that someone starts smoking in the first place.

Q. The Behavioral Research Center has conducted a number of studies looking at cancer survivors’ health behaviors, and has found that this group also struggles to adhere to recommended health guidelines. Cancer prevention strategies are just as important and perhaps even more important for survivors. What unique challenges do cancer survivors face that keep them from following recommended cancer prevention strategies? And what can they do to overcome these challenges?

Stein: Our research has found that, like the general population, cancer survivors often struggle to meet recommended health guidelines. For example, a study conducted by the Society’s Behavioral Research Center in 2008 found that while more than 90% of survivors were compliant with the recommendation not to smoke, less than half were meeting the physical activity recommendation, and fewer than 20% met the fruit and vegetable recommendation .

Indeed, prevention strategies are perhaps even more important for cancer survivors because they are at increased risk for new/recurrent cancers as well as other chronic conditions associated with their cancer treatment (known as late effects).

The good news is that a healthy lifestyle can ameliorate some of these problems and result in improved physical and mental health for survivors. And, there are specific guidelines for cancer survivors, published by the Society to help survivors learn how to live a healthy lifestyle. One strategy for survivors is to participate in a lifestyle intervention program or study.

Cancer survivors may in fact face unique challenges in overcoming barriers to healthy living. For example, due to the long-term effects of treatment, some survivors may have diminished physical functioning, which could reduce their ability to exercise. But, on the other hand, due to their disease experience, cancer survivors may have additional motivation to make health behavior changes and comply with health guidelines.

Some researchers and clinicians have referred to the cancer experience as a “teachable moment.” That is, the diagnosis of cancer is an opportunity for health care providers to talk to their patients about making health behavior changes. However, much still needs to be done to understand the motivational factors (at the individual, health system, and community levels) for health behavior change among cancer survivors.

Q. What more research needs to be done to figure out how to help more people employ basic cancer prevention strategies throughout their life?

Alcaraz: We need to figure out how to promote cancer prevention using a more holistic approach. For example, we’re starting to identify how to “bundle” prevention strategies to address multiple behaviors at the same time, but more research is needed on how to do this most effectively.

We also need to learn more about which strategies work best for different populations. And more research is needed to better understand social influences on preventive health behavior.

In addition, a growing area of research seeks to understand how information and communication technology can be used to promote and enhance cancer prevention behavior. We now have virtual communities that are connected through the Internet, smartphones, and social media. These present great opportunities – and some challenges – to reaching people with, and connecting people to, timely and accurate health information and prevention strategies.

Lastly, many effective behavioral change strategies are limited in their reach. Organizations such as the American Cancer Society can play a huge role in disseminating these evidence-based strategies, but more research is needed to identify the best ways to reach people who might benefit from these programs the most.