Why do people become obese? Is it genetics? Their behavior? A little of both? With all the new research coming out about the causes of obesity, it can sometimes be difficult to decide whether being overweight is the fault of the person with extra pounds or an unfortunate outcome of bad genes. A new study out this week has found that your opinion on this question can make a big difference in how you eat, exercise, and take care of your body. That, in turn, can lead to major health consequences down the road.
What do we know about what causes obesity?
There’s no question that obesity has become more and more common over the last several decades. In 1990, fewer than one in six adults in the U.S. was obese in most states. Today, more than one in three adults is obese and that number is even higher for those in middle and older age. Since this dramatic increase was first noted, research has exploded on what it is that might be causing American waistlines to expand and stay that way in spite of efforts to shrink them. The information to date about the cause is mixed.
Many studies in lab animals and in humans have indicated that there is a genetic component to a person’s weight. But that genetic component rarely determines what a person’s exact weight will be. Instead, it acts as a risk factor for weight gain in certain situations. That might be why people who appear to eat similar diets can have vastly different body weights and BMI scores. With the right setting, weight sticks more easily to some people than others. In the wrong one, weight doesn’t play favorites.
On the other hand, numerous studies have also shown that lifestyle affects weight and overall health, even when weight loss doesn’t occur. Lack of exercise and a high-sugar, high-fat, nutrient-poor diet have all been linked to obesity, diabetes, heart disease, certain types of cancer, and depression. It’s clear that the way you live your life makes a difference, even if you have genes that boost weight gain.
How did the researchers link weight attitudes to health?
The research team observed that the mixed picture of obesity causes doesn’t always make it to the public. Some people seemed to be getting the message that genetics were all that mattered, regardless of whether you exercised and ate well. Other research had shown that how hard a person works towards a goal is often based on whether they think the things they do will actually help them achieve that goal. Building on that idea, the team wondered how thinking that some people are born to be fat or born to be thin might affect the diet a person chose or how often they decided to exercise.
To test this, the researchers used data on more than 4,100 men and more than 4,600 women who participated in a national survey on health called the NHANES. The participants filled out a survey that asked about everything from their exercise levels to their diet to the attitudes about their own health and weight. The team took all of that health information and used statistical methods to see how attitudes about weight affected the food and exercise choices a person made.
What did the researchers find?
The team found that when people thought weight was unchangeable, even with exercise and a healthy diet, they were less likely to do things that were good for their health. These people also tended to have worse health overall. People who thought weight could change as a result of exercise and diet change tended to do those things more often and be healthier overall. Age also seemed to play a role. Older individuals who believed weight was unchangeable were less likely to exercise or eat well than their younger counterparts. While past studies had found indications of the effect these opinions might have, this study was the first to use objective data like weight and blood sugar to show that these negative beliefs were linked to actual health outcomes.
How does this affect me?
You probably have your own ideas about whether or not your diet or exercise routine make a difference to your health. This study shows that thinking you have no power to change your weight causes you to act in a way leads to worse health by nixing exercise and being careless with your diet. But their findings also show that believing you can take control of your weight can motivate you to do the things that do make a difference. Their work reminds us that our understanding of weight gain is far from complete. In spite of what the latest study or the newest book might say, the vast majority of research shows that eating healthy food and exercising regularly helps with weight loss and boosts health by lowering the risk of diseases like heart disease and cancer.