Obesity has become a major health concern worldwide, with rates continuing to rise. While many people understand that being overweight or moderately obese can negatively impact health, there is debate around whether someone who is severely obese can still be metabolically healthy. This article will examine the evidence around severe obesity and metabolic health, looking at the risks and complications associated with higher levels of excess weight as well as some of the individual factors that may allow some severely obese individuals to remain relatively healthy.
What is severe obesity?
Obesity is generally defined by body mass index (BMI), which is calculated using a person’s height and weight. A BMI of 30-34.9 is considered obese, while BMI of 35-39.9 is severely obese and BMI over 40 is morbidly obese. This equates to being approximately 100 pounds or more overweight for the average adult.
Severe obesity affects around 6% of adults in the United States. Rates have been steadily climbing along with increases in overall obesity levels. Severe obesity is associated with high risks of developing numerous health conditions including type 2 diabetes, high blood pressure, high cholesterol, heart disease, sleep apnea, osteoarthritis, fatty liver disease, kidney disease, and certain types of cancer.
Health risks of severe obesity
Some of the main health risks and complications associated with severe obesity include:
– Heart disease and stroke: Excess weight puts strain on the heart and raises risks for high blood pressure, heart attack, heart failure, and stroke. People with severe obesity have a higher risk of heart disease than those who are moderately obese or overweight.
– Type 2 diabetes: Obesity is one of the biggest risk factors for developing type 2 diabetes. Higher BMIs correlate to increased risk, and severe obesity has been associated with up to a 12-fold increase in diabetes risk compared to normal weight individuals.
– Metabolic syndrome: Severe obesity increases risks for metabolic syndrome, which is a cluster of conditions including high blood pressure, high blood sugar, unhealthy cholesterol levels, and excess abdominal fat. Metabolic syndrome increases risks for heart disease, diabetes, and stroke.
– Sleep apnea and breathing problems: Excess weight around the neck and throat can obstruct breathing during sleep, leading to sleep apnea. Severe obesity has been linked to very high rates of sleep apnea which can impair sleep quality.
– Joint and mobility issues: Excess body weight places a lot of pressure on joints, often leading to osteoarthritis, pain, and loss of mobility especially in the knees, hips, and lower back. This may limit physical activity.
– Cancer: Severe obesity increases risks for up to 13 types of cancer, especially endometrial, esophageal, pancreatic, colorectal, breast, ovarian, and kidney cancers.
– Fatty liver disease: Carrying substantial excess body fat can lead to the buildup of fat deposits in the liver, causing nonalcoholic fatty liver disease which may progress to cirrhosis and liver failure.
Can you be severely obese and metabolically healthy?
Some research has suggested that a subset of severely obese individuals may be “metabolically healthy” in that they do not show metabolic abnormalities like high blood pressure, cholesterol, and blood sugar typically associated with obesity.
Small studies have found that 10-35% of severely obese adults may be metabolically healthy, with normal insulin sensitivity, lipid levels, and blood pressure despite high BMI. However, there is debate around this concept. Some key points include:
– Being metabolically healthy but severely obese is not necessarily permanent. Studies show the metabolically healthy obese state tends to deteriorate over time.
– Even if bloodwork is normal, severely obese people still face higher risks of joint problems, sleep apnea, and stigma that can impact quality of life and health.
– Criteria for defining metabolically healthy obesity varies between studies. Those with a wider range of “healthy” markers may still face health risks.
– Large long-term studies show that compared to normal weight healthy people, metabolically healthy obese individuals still have higher risks for heart disease, stroke, and overall mortality over time.
– Obese people with normal metabolic markers may be more insulin resistant and at risk than their bloodwork suggests if tests are only done while fasting.
Overall, most evidence indicates severely obese people face increased health risks even in the absence of metabolic abnormalities. However, a subset does exist who may be protected from some short- and medium-term complications of obesity. Long-term risks remain elevated.
Factors that may promote metabolic health in the severely obese
What allows some severely obese individuals to maintain better metabolic health than others? Some contributing factors may include:
– Genetics: Some genetic differences may make people more or less susceptible to obesity-related metabolic abnormalities. However, genetics cannot fully explain metabolically healthy obesity.
– Fat distribution: Carrying more excess fat under the skin rather than viscerally around organs like the liver may promote better metabolic health.
– Lifestyle factors: Eating a very healthy diet, exercising regularly, not smoking, and limiting alcohol intake may help protect metabolic health despite obesity.
– Age and duration of obesity: Younger people who have been obese for a shorter time may be less likely to show complications than older people who have had obesity for decades.
– Ethnicity: Some ethnic groups such as African Americans may have lower obesity-related risk factors on average at a given BMI compared to other ethnicities like Caucasians.
– Access to care: Obese people undergoing frequent health screening and receiving medical management of risk factors when found may show fewer metabolic abnormalities.
Maintaining as healthy a lifestyle as possible can likely optimize metabolic health in someone with severe obesity. However, there are still likely individual differences in susceptibility versus resilience to complications.
Can you be healthy long-term while remaining severely obese?
While a subset of severely obese individuals may show fewer adverse metabolic effects than expected in the short term, remaining severely obese long term still appears to pose hazards to health.
Some research has found that compared with people who are not obese, metabolically healthy obese adults have:
– 2-3 times higher risk of developing heart disease over 10-20 years
– 60% higher risk of stroke over 20 years
– 2-4 times higher risk of developing diabetes over 5-10 years
– 1.5-2.5 times higher risk of dying from any cause over 10-25 years
Additionally, some studies indicate metabolically healthy obesity may be somewhat of a misnomer, as these individuals tend to show:
– Increased systemic inflammation
– Thicker carotid arteries indicating higher cardiovascular risk
– Elevated risk markers for fatty liver disease compared to normal weight
– Twice the risk of heart failure compared to healthy normal weight individuals
Overall, this research suggests that remaining severely obese long term likely eventually results in metabolic deterioration and higher likelihood of obesity-related diseases occurring. Carrying excess weight appears to tax the body over time.
However, developing obesity complications seems to depend on a mix of weight, genetics, environment, behaviors, and access to healthcare. Some people may progress faster than others. There likely is individual variability in thresholds where excess weight becomes harmful.
Can severe obesity be reversed?
Severely obese individuals who wish to improve their health outcomes should be encouraged that significant weight loss is possible and can undo some of the metabolic damage of obesity.
While challenging, every 10% weight loss confers health benefits, and over 20% loss may effectively eliminate higher risks associated with obesity. Just 5-10% weight loss can improve blood pressure, blood lipids, and blood sugar. Losing enough weight to shift BMI category from severely obese to overweight shows dramatic health improvements.
Evidence-based strategies for significant weight loss include:
– Following an overall healthy eating pattern with calorie reduction
– Increasing physical activity levels
– Behavioral therapy and lifestyle modifications
– In some cases, weight loss medications or bariatric surgery under medical supervision
With commitment to lifestyle changes and accessing appropriate medical care and counseling as needed, even severely obese individuals can successfully lose weight and reduce their health risks. The human body demonstrates an impressive ability to heal and regain metabolic function when excessive adipose tissue is shed.
The takeaway on severe obesity and health
Severe obesity is definitively associated with higher risks for developing type 2 diabetes, heart disease, cancer, joint problems, liver and kidney disease, and other complications. While a minority of severely obese adults may show no obvious metabolic abnormalities, available research suggests obesity will exert adverse effects over time if allowed to persist long term.
However, it also appears there is variability between individuals in susceptibility versus resilience to the detrimental impacts of excess weight. Some people’s metabolism seems able to adapt better initially before eventually becoming overloaded and showing dysfunction.
For anyone who is severely obese, focusing on improving overall health can aid in reducing complications in the meantime while weight loss efforts continue. Even modest weight reduction of 5-10% body weight can have meaningful benefits. Prioritizing metabolic factors through healthy lifestyles and medical management can optimize health status until more significant weight reduction is achieved.