Why do people become obesity

Several factors can play a role in gaining and retaining excess weight. These include diet, lack of exercise, environmental factors, and genetics. Some of these factors are discussed briefly in the following section.

The National Heart, Lung, and Blood Institute offers more information on the causes of overweight and obesity.

People gain weight when they eat more calories than they burn through activity. At some point in the development of mankind, the ability to store fat efficiently would have given one a survival advantage. In this day of food abundance, however, this same efficiency puts one at risk of developing obesity. Clearly, genetics alone is not the answer.

While an individual may be born with a genetic composition that predisposes them to develop obesity, not all of them will become affected by obesity. People do not become affected by severe obesity overnight. While children born with higher birth weights are at an increased risk of developing obesity in later life, most people with severe obesity were a normal weight at birth. Children are, however, quickly introduced into our obesity genic environment. Early on this particular child is a healthy weight for her age.

She graduates from high school and enters college. Due to her demanding college schedule, she finds that her meal patterns are disordered and she often just grabs something on the run.

Many times what she grabs is not the healthiest choice, but it is fast and easy. Late night study sessions usually involve chips, soda and an occasional pizza. It becomes increasingly difficult to find time to exercise and by the time freshman year is over, she gained 20 lbs. Over the summer, she is able to drop some weight by getting back to the gym and eating more sensibly.

By the time she graduates from college, she has gained 40 lbs. After graduation, she gets a great job in the city. She has a beautiful desk, which she sits behind for hours a day. During her breaks, she will meet her coworkers and they will share a candy bar and soda while discussing their life events. December 31st, she promises to lose the 10 lbs she has gained that year. Life continues and she meets a wonderful man whom she marries.

Now with her career and a home to take care of, finding time to exercise is almost impossible. Three diets undertaken this year, 15 pounds lost, 20 pounds regained. Those who could store body fat to live off during the lean times lived, and those who couldn't, perished. Today, of course, these thrifty genes are a curse rather than a blessing.

Not only is food readily available to us nearly around the clock, we don't even have to hunt or harvest it! In contrast, people with a strong genetic predisposition to obesity may not be able to lose weight with the usual forms of diet and exercise therapy.

Even if they lose weight, they are less likely to maintain the weight loss. For people with a very strong genetic predisposition, sheer willpower is ineffective in counteracting their tendency to be overweight. Typically, these people can maintain weight loss only under a doctor's guidance.

They are also the most likely to require weight-loss drugs or surgery. The prevalence of obesity among adults in the United States has been rising since the s. Genes alone cannot possibly explain such a rapid rise. Although the genetic predisposition to be overweight varies widely from person to person, the rise in body mass index appears to be nearly universal, cutting across all demographic groups. These findings underscore the importance of changes in our environment that contribute to the epidemic of overweight and obesity.

Genetic factors are the forces inside you that help you gain weight and stay overweight; environmental factors are the outside forces that contribute to these problems.

They encompass anything in our environment that makes us more likely to eat too much or exercise too little. Taken together, experts think that environmental factors are the driving force for the causes of obesity and its dramatic rise. Environmental influences come into play very early, even before you're born.

Researchers sometimes call these in-utero exposures "fetal programming. The same is true for babies born to mothers who had diabetes. Researchers believe these conditions may somehow alter the growing baby's metabolism in ways that show up later in life. After birth, babies who are breast-fed for more than three months are less likely to have obesity as adolescents compared with infants who are breast-fed for less than three months. Childhood habits often stick with people for the rest of their lives.

Kids who drink sugary sodas and eat high-calorie, processed foods develop a taste for these products and continue eating them as adults, which tends to promote weight gain. Likewise, kids who watch television and play video games instead of being active may be programming themselves for a sedentary future. Many features of modern life promote weight gain.

In short, today's "obesogenic" environment encourages us to eat more and exercise less. And there's growing evidence that broader aspects of the way we live — such as how much we sleep, our stress levels, and other psychological factors — can affect weight as well. Between and , the average man added calories to his daily fare, while the average woman added calories a day.

What's driving this trend? Experts say it's a combination of increased availability, bigger portions, and more high-calorie foods.

Practically everywhere we go — shopping centers, sports stadiums, movie theaters — food is readily available. You can buy snacks or meals at roadside rest stops, hour convenience stores, even gyms and health clubs. In the s, fast-food restaurants offered one portion size. Today, portion sizes have ballooned, a trend that has spilled over into many other foods, from cookies and popcorn to sandwiches and steaks.

A typical serving of French fries from McDonald's contains three times more calories than when the franchise began. A single "super-sized" meal may contain 1,—2, calories — all the calories that most people need for an entire day. And research shows that people will often eat what's in front of them, even if they're already full. Not surprisingly, we're also eating more high-calorie foods especially salty snacks, soft drinks, and pizza , which are much more readily available than lower-calorie choices like salads and whole fruits.

Fat isn't necessarily the problem; in fact, research shows that the fat content of our diet has actually gone down since the early s. But many low-fat foods are very high in calories because they contain large amounts of sugar to improve their taste and palatability. In fact, many low-fat foods are actually higher in calories than foods that are not low fat. The government's current recommendations for exercise call for an hour of moderate to vigorous exercise a day. Our daily lives don't offer many opportunities for activity.

Children don't exercise as much in school, often because of cutbacks in physical education classes. Many people drive to work and spend much of the day sitting at a computer terminal.