Obesity can be simply understood as having too much body fat. Dr. Malone, can you tell us about obesity?
Definitely, Major Spencer. Body fat in general can be measured by body mass index, or BMI. A BMI between 18.5 and 24.9 is considered normal weight. Overweight is defined as having a BMI between 25.0 and 29.9. Obesity is diagnosed at a BMI of 30.0 and above. Morbid obesity, defined as a BMI of 40.0 and above, is an additional threshold for patients that is especially dangerous.
Over a period of time, if someone eats more calories than they use or burn, they will store those extra calories as fat, and slowly gain weight. This increases the individual's risk of becoming obese. The optimal balance between calories in and calories out differs for each person because the general ability to burn calories depends on muscle mass, which is initially determined by height. However, factors that contribute to weight gain are often the same for most people, including:
- Activity level
- Lifestyle, and
In some cases, microbiome, a type of bacteria colonized in the gut, may also contribute to weight gain.
When a person consumes more calories from food and drink than they use through physical activity, their body stores the excess calories as fat. A few extra pounds may not seem like much, but over months and years, the effect can be quite significant. Too much fat in the body can cause serious health problems. These problems can include:
- High blood pressure
- High cholesterol
- High blood glucose
- Heart disease
- Type 2 diabetes
- Vascular disease
- Joint problems
- Liver disease
- Some types of cancer, and
- Difficulty getting a good physical exam or accurate interpretation of imaging studies due to the interference of fat tissue
The good news is that if an adult is obese, losing a relatively small percentage of their body weight -- as little as five to 10 percent -- can potentially delay or prevent some of these consequences.