What are the environmental factors that can cause obesity?

Scientists say that a single environmental factor is by far the biggest cause of obesity: food. Research shows that your "food environment" has a huge impact on what you eat—and how much you eat. For instance, if you keep a lot of sweets and high-fat foods around your house, then you're likely to eat them—and gain weight. The same is true in the workplace: If the break room has vending machines filled with candy, chips and soda, you may be tempted to consume these diet-busting treats.

In a larger sense, scientists say that some communities in the United States have unhealthy food environments in which highly fattening foods are cheap and plentiful. The problem is particularly serious in low-income neighborhoods, where it can be difficult to find grocers who offer healthy foods such as fruit, vegetables and whole grains.

To maintain a healthy weight, try to become more aware of your food environment and how it affects what you eat. Keep in mind, too, that physical activity has declined in recent decades, so working more activity into your day can also help you burn off the calories you consume.