Non-alcoholic fatty liver disease (NAFLD). Your liver normally has some fat, but when more than 5 to 10 percent of its weight is fat, the condition is called a fatty liver or steatosis. Before the obesity epidemic, drinking alcohol in excess was the primary cause of a buildup of extra fat in liver cells. Non-alcoholic fatty liver disease—fatty liver not caused by alcohol—is now becoming more and more prevalent. NAFLD tends to develop in people who are overweight or obese or who have diabetes, high cholesterol or high triglycerides. It now affects up to 25 percent of people in the United States. NAFLD may cause the liver to swell, a condition called steatohepatitis, which can lead to the scarring of cirrhosis over time and possibly liver cancer or liver failure.
Heart disease. Traditional thinking attributes much of the heart disease seen in severely overweight people to other risk factors, such as diabetes and high blood pressure, both of which often affect people who are obese. However, recently researchers found that obese people without overt heart disease still experience silent cardiac damage that fuels their risk for heart failure in the future. They did this by using a very sensitive blood test that detects the presence of the heart enzyme troponin T, which indicates heart muscle injury. They found that elevated levels of troponin T corresponded to increases in body mass index, or BMI, a measure of body fat based on a person’s weight-to-height ratio, and the higher a person’s BMI, the higher their level of the enzyme. Compared with people of normal weight, people who are severely obese have more than twice the risk of developing heart failure, a condition in which the heart muscle doesn’t pump efficiently over time. All people with elevated troponin levels, regardless of BMI, have a higher risk of developing heart failure. And together the effects of elevated troponin and severe obesity are particularly striking: Severely obese people with elevated troponin levels were nine times more likely to develop heart failure than people with normal weight and undetectable troponin levels.
Shortened lifespan. According to Canada’s Research Institute of the McGill University Health Centre and McGill University, the life expectancy of people who are overweight or obese can be cut short by their extra pounds—people who are very obese could lose up to 8 years of life, people who are obese could lose up to 6 years, and people who are overweight could lose up to 3 years. The age at which the excess weight was gained matters, too—the earlier in life, the worse the health outcome. And, if they also develop diabetes or cardiovascular disease at a younger age, they can be robbed of nearly two decades of healthy life. Using the health records of nearly 4,000 people, the research team was able to develop a computer model to help understand how excess body weight cuts years off your life and leads to heart disease and diabetes earlier in life. Infant mortality. Pregnant women who are overweight or obese may be putting their baby’s health at risk as well as their own. Though the exact causes haven’t yet been pinpointed, obesity in early pregnancy is associated with an increased risk of infant mortality, and the more obese the mom is, the greater the risk to the baby. Babies do best when mom is at a normal body weight before and during pregnancy—that’s why women are encouraged to lose any excess pregnancy weight before getting pregnant again.
Obesity-related cancers. You might not think of obesity as a cancer threat, but it is, particularly for women. Worldwide in 2012, excess weight was responsible for 5.4 percent, or 345,000, of new cancer cases in women, close to three-quarters of which were post-menopausal breast, endometrial and colon cancers, and 1.9 percent, or 136,000, of new cancer cases in men, over two-thirds of which were colon and kidney cancers. Researchers estimate that 25 percent of all these obesity-related cancers were attributable to the rise in BMI in the population over the prior 20 years and could have been avoided. The percentages are far higher in developed countries—nearly a quarter of all new obesity-related cancers globally are occurring in North America. However this is still a global concern—obesity around the world has doubled since 1980.