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Last updated January 15, 2020. 7 minute read

These are the health risks of having a BMI >30

People with obesity have an increased risk of several medical conditions, including heart disease, type 2 diabetes, high blood pressure, strokes, breathing problems, liver disease, gallbladder disease, cancer, pregnancy issues, arthritis, and depression.

Dr Chimene Richa Md Written by Chimene Richa, MD
Reviewed by Tzvi Doron, DO

Obesity is a common chronic medical condition; according to the Centers for Disease Control and Prevention (CDC) close to 40% of adults and 20% of children (ages 2-19) in the United States are classified as obese; that’s equal to approximately 93.3 million people in the US (CDC, 2016). Obesity is classified by using a person’s Body Mass Index (BMI), which is a measurement of your weight in kilograms (1 kilogram equals 2.2 pounds) divided by your height in meters squared (1 meter equals ~3 feet 3 inches). Several online calculators can help you figure out your BMI; you can click here to calculate your BMI. Using that number, you can determine which of the following definitions applies to you:

  • Normal weight: BMI of 18.5 to 24.9 kg/m2 
  • Overweight: BMI of 25 to 29.9 kg/m2 
  • Obesity: BMI of 30 kg/m2 or higher 

Vitals

  • Obesity is a chronic medical condition that affects close to 40% of adults and 20% of children in the United States.
  • Obesity is defined as having a Body Mass Index (BMI) of 30 kg/m2 or higher.
  • People with obesity have an increased risk of several medical conditions, including heart disease, type 2 diabetes, high blood pressure, strokes, breathing problems, liver disease, gallbladder disease, cancer, pregnancy issues, arthritis, and depression.
  • The best way to lower your risk of obesity-related health problems is to lose at least 5% of your body and adopt healthy diet and exercise patterns.

What are the health risks of obesity?

Studies have shown that as BMI increases, so do your health risks; obesity has been shown to increase the risk of heart disease, type 2 diabetes, high blood pressure, strokes, breathing problems, liver disease, gallbladder disease, pregnancy issues, and depression (Bray, 2017).

Heart disease

People with obesity have a higher risk of heart disease because they tend to have higher levels of the risk factors that contribute to heart disease, including:

  • High blood pressure (hypertension)
  • Elevated low-density lipoprotein (LDL) cholesterol levels
  • High triglycerides
  • High blood sugar (hyperglycemia)

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These risk factors make it more likely that fatty deposits (atherosclerosis) will build up in your arteries, causing them to harder and restrict the flow of blood. Atherosclerosis can lead to a blockage of arteries to the heart, resulting in a heart attack (myocardial infarction), heart failure, chest pain (angina), heart rhythm problems, and death. Furthermore, the heart has to work harder to pump blood throughout the body in people with obesity.

Type 2 diabetes

Obesity is a risk factor for developing type 2 diabetes (Riaz, 2019). In diabetes, your blood sugar is higher than average, and your body is unable to keep the levels in a healthy range. Usually, your body’s cells use the hormone insulin to move sugar out of the blood and into the cells where it can be used for energy. People with obesity often have cells that don’t respond to insulin like they should. This is called insulin resistance, and it can cause blood sugar levels to go up. If your blood sugar stays elevated, the cells that produce insulin may gradually fail from working extra hard to produce enough insulin to move the sugar out of the blood (NIDDK, 2015). Diabetes, in turn, is a risk factor for several health problems, including heart disease, kidney disease, stroke, blood flow problems, and blindness.  

High blood pressure

Due to the excess weight and larger body size, the heart needs to pump harder and move more blood throughout the body to nourish all of the tissues (Bray, 2017). This increased effort and volume results in high blood pressure (how hard the blood pushes on your blood vessel walls) and puts a strain on the blood vessel walls. High blood pressure can also damage your kidneys; the kidneys play an essential role in regulating blood pressure, and damage can cause the blood pressure to elevate further. High blood pressure is also a risk factor for heart disease, kidney disease, and strokes. 

Strokes

Strokes happen when the blood flow to the brain is decreased, either by a blood clot or broken blood vessel in the brain. High blood pressure, diabetes, and high cholesterol increase the risk of strokes. Since obesity increases your risk of these factors, it can also increase your risk of having a stroke. 

Sleep apnea and other breathing problems

Obesity is one of the most significant risk factors for sleep apnea. Sleep apnea is a breathing condition where you repeatedly stop and then restart breathing for short periods during sleep. Over time, these can cause daytime sleepiness, high blood pressure, heart rhythm problems, and even heart failure. Approximately 60% of people with obesity have obstructive sleep apnea (OSA) (Drager, 2013). In one study looking at over 300 people with obesity and diabetes, 86% also had sleep apnea (Foster, 2009). Asthma is another breathing problem that affects people with obesity more than normal weight or overweight people; according to the CDC, 11-14% of people with obesity have asthma compared to 7-8% in the normal weight category (CDC, 2016). 

Liver disease

Fatty liver disease, also known as nonalcoholic steatohepatitis (NASH), is a condition where fat builds up in the liver and may lead to liver damage, scar tissue (cirrhosis), and liver failure. Obesity, along with elevated cholesterol levels and type 2 diabetes, is a significant factor for developing this liver disease (Caldwell, 2004). Also, obesity and diabetes are risk factors for the development of hepatocellular carcinoma (liver cancer); people with fatty liver disease are also at higher risk for developing hepatocellular carcinoma (Caldwell, 2004).

Gallbladder disease

People with obesity are more prone to developing gallstones. Increasing body fat increases the amount of cholesterol in the bile stored in the gallbladder; this increased cholesterol leads to the development of gallstones, which can be painful and require surgery (Bray, 2017).

Cancers

Obesity is a risk factor for multiple cancers; one theory is that fatty tissue produces hormones (like estrogen) along with multiple growth factors that can trigger the abnormal growth characteristic of cancer. According to the CDC, people with obesity are at increased risk for at least 13 different types of cancer, including cancers of the following (Steele, 2017):

  • Breast (in women after menopause) 
  • Colon and rectum
  • Endometrium (lining of the uterus)
  • Gallbladder
  • Kidney
  • Liver
  • Gastric cardia (a type of stomach cancer)
  • Ovary
  • Pancreas
  • Thyroid
  • Esophagus
  • Meningioma
  • Multiple myeloma

Reproductive problems

Obesity can decrease the ability to have an erection (erectile dysfunction) in men and cause abnormal or irregular periods in women; both of these can make it more difficult to conceive a child. Gaining too much weight during pregnancy or having a BMI over 30 before pregnancy are both risk factors for pregnancy problems. Several pregnancy-related complications that can occur in women with obesity include (Rhoton-Vlasak, 2017):

  • Gestational diabetes and hypertension
  • Preeclampsia (very high blood pressure and kidney or liver damage during pregnancy)
  • Increased risk of miscarriage
  • Postpartum depression
  • Increased risk of congenital abnormalities 
  • Stillbirth

Arthritis

Obesity increases the risk of arthritis in mainly two ways; the excess weight increases the load on weight-bearing joints and promotes inflammation. Both of these mechanisms contribute to osteoarthritis and degeneration of joints, especially the hip and knee. One study estimated that 69% of knee replacements and 27% of hip replacement are due to being overweight or obese (King, 2013).

Depression 

Many people with obesity also have depression, and many depressed individuals also suffer from obesity. Social stigma, sexual problems, shame, isolation, and decreased quality of life, all contribute to the development of depression in people with obesity. However, there may be a more scientific link as well; one study has shown a relationship between high levels of leptin, a hormone secreted by fatty tissue, and atypical major depressive disorder.

How to lower your risk of obesity-related health problems

According to the National Institutes of Health (NIH), weight loss of as little as 5% of your body weight can decrease your risk of many of the diseases associated with obesity (NIDDK, 2015); for example, if you weigh 200 pounds, losing 10 pounds can improve your health. Losing weight slowly and steadily, between ½ and 2 lbs a week, is the safest way to achieve weight loss. Adding 150-300 minutes of physical activity a week and performing strengthening exercises can also help you stay healthy.

Diet also plays a role in weight loss and decreasing your health risks. Federal dietary guidelines recommend the following eating pattern guidelines to maintain a healthy weight:

  • A variety of vegetables from all of the different types, including dark green, red and orange vegetables, legumes (beans and peas), starchy vegetables, etc
  • Fruits, especially whole fruits
  • Grains, with at least half being whole grains
  • Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages
  • A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products
  • Use unsaturated fats, like oils, and limit saturated and trans fats
  • Limit sugar and sodium intake

Lastly, smoking and alcohol use are independent risk factors for many health conditions; avoid smoking, and limit alcohol use to maintain a healthy lifestyle.