Roughly two-thirds of Americans are overweight. Obesity results when body fat accumulates over time and as a result calories taken in exceed calories expended. It can run in families and is associated with diabetes, hypertension, heart disease, and certain cancers.
Sociologists say evolution is partly to blame. Historically, food was scarce and our bodies fended off starvation by becoming effective fat storage machines. Losing weight was a stressor.
Today, food is relatively abundant, but we live much more sedentary lives. Gone are the long, tiring days of toiling in the fields. Many of us earn a living sitting in front of a computer screen and eating far more calories than we burn which could account for why obesity has reached epidemic proportions.
The science of weight loss is still emerging. Researchers are learning that other factors—including heredity—affect how the body responds to and processes food. Hormones seem to play a role and scientists are also investigating the naturally occurring bacteria in our intestines. (Apparently, some bacteria absorb more fat than others.)
Many genes are also associated with the development of obesity and seem to regulate how our bodies capture, store, and release energy from food. So an overweight person might be fighting more than his inability to control what he puts in his mouth and how much he exercises.
Recent studies suggest that varying satiety levels and the desire to eat higher-calorie foods may also be influenced by heredity. Unfair as it seems, some people are biologically protected against accumulating extra fat while others are prone to accumulating it.
Determining how much is genetic and how much is learned behavior (family eating habits, food preferences, seeking comfort or reward from food, etc.) is another complex piece of the puzzle.
Sweet Tooth? Blame It On Your Mother and Then Hit the Gym
Scientists first identified the FTO gene—"fat mass and obesity-associated" gene—several years ago. But according to Frank DiPino, PhD, a professor of biology at Misericordia University in Pennsylvania the picture isn't yet clear.
"The FTO gene does appear to increase appetite and preference for high calorie foods, but there's still a lot we don't know about it."
Erin Keen-Rhinehart, a neuroscientist at Susquehanna University explains that although the FTO gene is produced in the areas of the brain that are responsible for appetite regulation and increases in response to food deprivation, in human studies it resulted in an average of less than two pounds of weight gain.
"The FTO gene is merely a risk factor for developing obesity and responsible for only modest increases in body weight," says the Pennsylvania-based scientist.
Keen-Rhinehart, DiPino and other experts agree that the negative implications of having the FTO gene are well counteracted by physical exercise.
"It's not just about adding more exercise," says professor DiPino. "It appears that exercise alters the FTO gene in a good way. It turns down the volume so it does less damage."
Why Is Dieting So Difficult?
We all know that exercise is important for overall health and weight loss. The formula is simple: Eat less calories and exercise more. So what makes losing weight such a difficult task?
According to the Centers for Disease Control and Prevention (CDC), there is tremendous variation in an individual's response to fat, sugar, and carbohydrates. Plus, a number of biological and genetic factors are involved in determining how much food is too much for any individual.
Science is also starting to reveal some distressing news about the weight-reduced body. It appears that a dieter's body is metabolically different—in a negative way—than a similar-size body that has not dieted.
Changes that occur after weight loss can translate to a huge caloric disadvantage of 250 to 400 calories. In one study, muscle biopsies taken before, during, and after weight loss showed that in some people, muscle fibers undergo a transformation which makes them burn 20 to 25 percent fewer calories during everyday activity and moderate aerobic exercise than those of a person who is naturally at the same weight. In other words, it's possible that the person who is naturally at the same weight as a dieter can actually eat more and still retain his weight.
Dieters not only have to exert tremendous will power to avoid fattening foods, but they also have to work harder to burn calories. No wonder so many throw in the towel!
Until science comes up with more solutions to our weight-loss woes, watch what you eat, and always be vigilant about exercise. "Weight is a multi-factor, complicated issue," says DiPino. "Science is on the right track but, all the parts have yet to come together. "
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