“Obesity” is a term we encounter ever more often as the weight of the nation increases. Though most people are aware that “obese” means someone is extremely overweight, in reality there is more than mere weight involved. The definition of obesity is a BMI (Body Mass Index) of 30 or higher*. BMI is a rough formula for estimating how much body fat a person has, and obesity is a condition of having too much body fat in comparison to lean muscle.
Obesity is further divided into three categories:
Class I obesity – BMI of 30 to 34.9
Class II obesity – BMI of 35 to 39.9
Class III obesity – BMI of 40 or above, also known as extreme obesity.
The majority of obese people fall into the Class I or Class II category, but all types of obesity are on the rise.
What causes obesity?
While there are a handful of medical conditions, such as Cushing’s syndrome (caused by prolonged exposure to the hormone cortisol) or Prader-Willi syndrome (a genetic disorder which causes insatiable hunger) that can cause obesity, they represent only a tiny fraction of cases. Nearly all cases of obesity are caused by lifestyle issues, especially:
- Unhealthy diet and poor eating habits. The majority of people eat far more than they need, often without even realizing it. In addition, the typical American diet is very high in overly processed foods, high-calorie beverages, and other foods that promote fat gain.
- Inactivity. While our food consumption has increased, our lifestyles have become increasingly sedentary. This scenario makes weight gain inevitable as we take in far more calories than we burn.
Other factors such as stress and chronic low-grade sleep deprivation may play a role, but diet and inactivity are the primary drivers of the obesity epidemic.
*BMI is calculated using a mathematical formula and does not directly measure body fat. Therefore, extremely muscular people such as athletes may have a BMI that does not reflect their actual fat to lean mass ratio.
A variety of factors can contribute to obesity. Common risk factors include:
Obesity tends to run in families—you’re more likely to be obese if one or both parents are also obese. And although it may be tempting to put this down to genetics, it’s more often a result of family habits and traditions. These habits lead to obesity for parents, who pass the same habits on to their children. You’re also more likely to become obese if you have friends who are obese.
Poor dietary habits and food choices.
High-calorie meals, underconsumption of vegetables and fruits, fast food, sugary drinks, and oversized portions are all features of many typical meals and all lead to weight gain.
To avoid weight gain, our bodies must burn as many calories as we take in. The more sedentary your lifestyle, the easier it is to eat more calories than you burn.
Social and economic issues,
such as lack of cooking skills, lack of funds to buy healthy food (unhealthy food is unarguably much less expensive) all promote obesity.
Both stress and sleep lead to hormonal changes which make you more likely to gain—and retain—weight. In addition, stress and sleep deprivation also make you crave sweets and other high-carbohydrate foods, which contribute to weight gain.
A person can become obese at any age—even as a child or an infant—but ther risk of obesity increases at middle age and beyond. This is due to a combination of hormonal changes, decreased muscle mass, and lower activity level. These changes decrease calorie needs, but too often our eating habits don’t change along with our calorie needs. This means that what doesn’t affect us at age 20 or 30 may cause weight gain at age 40 or 50.
Weight gain is a normal and natural part of pregnancy, and a normal-weight woman should gain 25 to 35 pounds in total. However, the majority of women gain more than this, and many find it difficult to lose the extra pounds once their baby is born. This retained weight is a risk factor for obesity.
Many people gain weight after quitting smoking.
Some medications can cause weight gain. These include but are not limited to:
- Anti-seizure medications
- Anti-psychotic medications
- Birth-control pills
and even some diabetes medications. If you’re taking medication and find yourself inexplicably gaining weight, talk to your doctor.
Those who are obese are more likely to develop:
- High blood pressure
- Type 2 diabetes
- Cardiovascular disease
- Gallbladder disease
- Breathing disorders, including sleep apnea (in which you have episodes during sleep where you stop breathing)
- Irregular periods
- Erectile dysfunction
- Fatty liver
- Some types of cancer, including cancer of the colon, rectum, esophagus, liver, pancreas, kidney, prostate, ovaries, breast, cervix, or uterus