The Possible Link Between Obesity and Cancer


Studies show those who are overweight or obese are at greater risk for many diseases. While studies can’t conclusively prove that obesity causes cancer, there is growing evidence that higher amounts of body fat are consistently associated with increased risks for developing certain types of cancers.

One of the possible mechanisms to understanding the link between obesity and certain cancers is that obese people typically have chronic low-level inflammation. Over time, this condition can cause DNA damage that leads to various illnesses, cancer included. It’s also known that fat tissue produces excess amounts of the hormone estrogen, and these high levels are associated with increased risk of breast, endometrial and ovarian cancers.

Knowing the connection between obesity and cancer doesn’t always make it easier to change eating habits or lose excess weight. For most of us, good food is associated with pleasure, social celebrations, and for many, emotional support.

But if you’re ready to commit to making changes that can reduce your risks, there are proven strategies to practice. The National Weight Control Registry (NWCR) compiles data from persons who have successfully lost weight and kept it off for at least one year. Strategies will vary according to each individual but as a general guideline, the following may help you drop those extra pounds and reduce your risks along the way.

Successful NWCR strategies for successful weight loss included:

  • 98% of people had to modify their food intake in some way.
  • 94% increased their physical activity; with walking being the most commonly reported form of activity. Barriers to exercise such as being too tired, having no time or no one with whom to exercise, or finding it too hard to maintain an exercise routine were associated with being unsuccessful at losing weight.
  • 90% exercised about one hour per day on average
  • 78% ate breakfast every day
  • 75% weighed themselves at least once per week
  • 62% watched less than 10 hours of television per day (reduced their sedentary time)
  • 55% received help with weight loss goals by joining commercial weight loss programs or working with a physician, dietitian and nutritionist

While the recommendations may seem straightforward, following them may not be easy for most people. Studies show that over the long-term, many individuals regain the weight they have lost. “Only about a quarter of people who intentionally lose 10% of their body weight or more are able to keep it off for a year or longer,” says Chi-Chen Hong, PhD, Associate Professor of Oncology at Roswell Park Comprehensive Cancer Center.  “Looking at the science, individuals who are able to maintain weight loss exhibited more frequent self-monitoring of food and calorie intake, selected lower calorie foods, planned meals in advance and weighed regularly. The key to success is not to just let things go, but instead work towards long-term adherence to diet and exercise.”

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Dr. Chi-Chen Hong recommends integrating the following lifestyle changes gradually.

  • Keep a food log.
  • Limit high-calorie foods.
  • Drink fewer beverages high in fat and/or added sugar (beware of fancy coffee drinks!) and eat less fast fried food.
  • Eat more low-calorie foods like vegetables and fruits to reduce fat intake. The added fiber has the bonus of helping you feel fuller.
  • Make sure you get enough sleep since sleep deficit is associated with obesity.
  • Eating earlier in the day may help with weight loss. In a 20 week 2013 study, those who ate earlier in the day lost more weight than those eating later. In another study in which women ate either a large breakfast or large dinner, with lunch being the same size, the women who ate more calories earlier in the day reported greater weight loss, along with reductions in waist circumference and lower triglycerides than women who ate later in the day. Eating after 8 p.m. at night has also been associated with higher levels of Body Mass Index, or BMI.
  • Add more physical activity throughout the day. Park a little further away from where you are going. Take the stairs instead of an elevator if you can manage. Staying active can also reduce levels of inflammation.

To stay motivated and benefit from the support of others with similar goals, Dr. Hong recommends joining a group weight loss program which may work better than individual counseling programs. “Social support, better coping strategies and the ability to handle life stressors are factors associated with successful weight loss maintenance,” says Dr. Hong.