Obesity has been an epidemic in the United States for more than 40 years, and it’s getting worse. According to the Centers for Disease Control and Prevention (CDC), 42 percent of U.S. adults are obese. And nearly 20 percent of children and teens are considered obese.
These stats are concerning because obesity is a medical problem that increases the risk of many other diseases and health problems, including type 2 diabetes, high blood pressure, some forms of cancer and heart disease, as well as depression and arthritis. Studies have shown that millions of people worldwide die each year from obesity-related conditions.
In response to the obesity epidemic, obesity medicine specialists are working to better understand the science of obesity, factors that contribute to it and the best possible way to treat it.
Andrea Coviello, MD, is the medical director of the UNC Health Medical Weight Program and John Buse, MD, PhD, is director of the UNC Health Diabetes Center. We talked to these two leading obesity medicine specialists to learn more.
Obesity is a medical condition.
Obesity is a complex disease in which a person has too much body fat.
“Excess body fat increases the risk for about 200 other diseases—some cancers, dementia, diabetes, gout, heart disease, lung disease, depression, arthritis, gallbladder disease, liver disease,” Dr. Buse says. “It is the fundamental problem of our life from a health perspective.”
Body mass index, known as BMI, is often used to diagnose obesity. You are considered obese if you have a BMI over 30 and overweight if you have a BMI of 25 or more. For example, a 5-foot-4-inch person who weighs 175 pounds has a BMI of 30.
“BMI is a proxy measure for fat, and represents weight adjusted for height, so it’s not a perfect measure, but it’s a better measure than weight alone,” Dr. Coviello says. “A BMI of 30 or more is associated with earlier mortality, and mortality increases by about 30 percent for every five-unit increase in BMI.”
Genetics and the environment can play a role in causing obesity.
Many factors contribute to obesity including genetics and environmental variables, combined with diet and physical activity levels.
About 7 in 100 people are born with a genetic variant that is associated with early weight gain and obesity, before age 10, Dr. Coviello says. “We’ve increasingly identified the genes that can cause obesity and are beginning to have the ability to genetically screen certain individuals.”
For the vast majority of people, obesity is a complex disorder, and multiple environmental factors contribute to the rising obesity epidemic.
“Since the 1980s, we’ve become much more sedentary, we get less sleep, and we have seen the evolution of high-density, high-caloric foods that don’t have high-quality nutrients in them but have high amounts of fats and sugars,” Dr. Coviello says.
In addition, obesity medicine researchers like Dr. Coviello believe there may be chemicals or compounds in the environment that we are exposed to through food or water that disrupt our endocrine system. The endocrine system controls some aspects of metabolism and hormone production and, therefore, can play a role in weight by influencing appetite, fat accumulation, blood sugar and energy levels.
Other endocrine disrupters include lack of exposure to natural light and dark cycles, which can affect sleep-wake cycles, and elevate cortisol levels from chronic stress.
“We think these factors have changed what genes are turned on and off in the body. This is called epigenetics,” Dr. Coviello says. “It’s not your genetic blueprint, which is the genes you’re born with, but it’s the factors in your environment that then act to turn certain genes on or off. We think there are a lot of epigenetic effects on the tendency to gain weight over the course of your life.”
The good news is that these epigenetic changes are reversible, making them appealing targets for obesity treatment.
A one-size-fits-all approach to weight loss does not work.
There is no magic pill that will cure obesity, but even modest weight loss can improve or prevent the health problems associated with obesity. A healthier diet, increased physical activity and modified behavior can help you lose weight.
“Lifestyle intervention is the first line of therapy—making appropriate food choices, recipe modification to reduce calories or hunger or both and physical activity,” Dr. Buse says. “These are effective in helping many people lose 5 percent of their weight—occasionally 10 percent.”
If you need to lose more than 10 percent of body fat, lifestyle changes alone may not be enough.
“After being at a certain weight for a period of time—and we don’t know what period of time that is—your body will try and keep your weight at that level,” Dr. Coviello says. “If you successfully lose weight through lifestyle changes such as diet and exercise, once you lose about 8 or 10 percent of your body weight, your body actually starts to physiologically adapt to try and maintain that prior weight and even make you regain the weight you lost.”
These adaptations are shifts in the hormones that regulate appetite—the hunger and satiety hormones that your body secretes after you eat.
“They are altered in a way that favors increased food intake and weight regain, so your satiety hormones go down, your hunger hormone, ghrelin, goes up after successful weight loss, and your energy expenditure goes down,” Dr. Coviello says. “Your body senses less fuel stores, less fat mass, so it reflexively turns down energy expenditure to conserve fat mass for fuel.”
In other words, you gain the weight back because you feel hungry more and your body holds on to fat. When this occurs, your doctor may talk to you about weight-loss medicines or surgical weight-loss procedures to help treat your obesity.
“It’s easier to cure cancer than to get people to lose 10 percent of their body weight and keep it off for a year,” Dr. Buse says. “That’s just very hard to do with diet and physical activity alone.”
New anti-obesity drugs are proving effective.
Prescription weight-loss drugs work in different ways to treat obesity. For example, some anti-obesity medications may help you feel less hungry or full longer or decrease your appetite.
A new wave of these anti-obesity drugs have exploded in popularity and have been life-changing for many people who struggle with weight.
“We have begun to leverage drugs that I have been working on as a diabetes doctor for 20 years for managing diabetes to help with weight loss in people without diabetes,” Dr. Buse says.
These medicines mimic the hormones produced in the intestine and the colon that get secreted in response to eating, specifically the gut hormone glucagon-like peptide‐1 (GLP-1), which regulates appetite.
“GLP-1 alters how fast you digest your food from the stomach through the gut—slowing that a little bit—and it increases satiety after you’ve eaten to make sure that you feel full and stop eating at the end of a meal,” Dr. Coviello says. “With the foundation of lifestyle management, these drugs can be very successful.”
While promising, anti-obesity medications can be expensive without insurance, and if you do not meet the Food and Drug Administration’s criteria to take them, you may have trouble getting your insurance to cover the cost.
Weight-loss surgery can be the best solution for some people.
If you have a BMI of 35 to 39.9 and a history of obesity-related conditions such as high blood pressure, type 2 diabetes, infertility, high cholesterol or sleep apnea, or a BMI of at least 40 regardless of any obesity-related diseases, you might be a candidate for weight-loss surgery, according to guidelines set by the National Institutes of Health.
“If you qualify for bariatric surgery, it can be more cost-effective, as you don’t have the ongoing cost of taking a weight-loss drug week after week,” Dr. Buse says. “Most people have an excellent response, have no complications and achieve 30 percent weight loss.”
The goal of treating obesity as a chronic medical disease is not about achieving a certain size. It’s about health.
“Until we had the tools, we often treated obesity as a side issue. We were working on their diabetes or their arthritis and they were overweight, but we couldn’t do much about it,” Dr. Buse says. “But now, we have things we can do about it, and the hope is that we can attack the root of the problem, which is the obesity as opposed to all the manifestations of the problem. If we just took care of the obesity, the rest could go away.”
If you’re concerned about your weight or weight-related health problems, ask your doctor about obesity management. Need a doctor? Find one near you.