On a very simple level, your weight depends on the number of calories you consume, how many of those calories you store, and how many you burn up. But each of these factors is influenced by a combination of genes and environment. Both can affect your physiology (such as how fast you burn calories) as well as your behavior (the types of foods you choose to eat, for instance). The interplay between all these factors begins at the moment of your conception and continues throughout your life.
The calorie equation
If you consistently burn all of the calories that you consume in a day, you will maintain your weight. If you consume more energy (calories) than you expend, you will gain weight.
Genetic influences
Everyone knows some people who can eat ice cream, cake, and whatever else they want and still not gain weight. At the other extreme are people who seem to gain weight no matter how little they eat. Why? What are the causes of obesity? What allows one person to remain thin without effort but demands that another struggle to avoid gaining weight or regaining the pounds he or she has lost previously?
Genes are probably a significant contributor to your obesity if you have most or all of the following characteristics:
You have been overweight for much of your life.
One or both of your parents or several other blood relatives are significantly overweight. If both of your parents have obesity, your likelihood of developing obesity is as high as 80%.
You can't lose weight even when you increase your physical activity and stick to a low-calorie diet for many months.
Related Topic: Fighting and Preventing high cholesterol with a diet
Genes are probably a lower contributor for you if you have most or all of the following characteristics:
You are strongly influenced by the availability of food.
You are moderately overweight, but you can lose weight when you follow a reasonable diet and exercise program.
You regain lost weight during the holiday season, after changing your eating or exercise habits, or at times when you experience psychological or social problems.
These circumstances suggest that you have a genetic predisposition to be heavy, but it's not so great that you can't overcome it with some effort.
At the other end of the spectrum, you can assume that your genetic predisposition to obesity is modest if your weight is normal and doesn't increase even when you regularly indulge in high-calorie foods and rarely exercise.
People with only a moderate genetic predisposition to be overweight have a good chance of losing weight on their own by eating fewer calories and getting more vigorous exercise more often. These people are more likely to be able to maintain this lower weight.
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.
Environmental causes of obesity
Genetic factors are the forces inside you that help you gain gained 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." Babies of mothers who smoked during pregnancy are more likely to become overweight than those whose mothers didn't smoke. 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 breastfed for more than three months are less likely to have obesity as adolescents compared with infants who are breastfed 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.
The record of the Center for Disease and Control has it that between 1971 and 2000, the average man added 168 calories to his daily fare, while the average woman added 335 calories a day. What's driving this trend? Experts say it's a combination of increased availability, bigger portions, and more high-calorie foods.
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 1,500–2,000 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 gone down since the early 1980s. But many low-fat foods are very high in calories because they contain large amounts of sugar to improve their taste and palatability. Many low-fat foods are higher in calories than foods that are not low fat.
The Exercise equation
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. Because we work long hours, we have trouble finding the time to go to the gym, play a sport, or exercise in other ways.
Helpful Topic: Effect of smoking cigarettes and its benefit of quitting
Instead of walking to local shops, we drive to one-stop megastores, where we park close to the entrance, wheel our purchases in a shopping cart, and drive home. The widespread use of vacuum cleaners, dishwashers, leaf blowers, and a host of other appliances takes nearly all the physical effort out of daily chores and can contribute to one of the causes of obesity
Comments
Post a Comment