Obesity is a complex health condition involving an excessive amount of body fat that increases the risk of other diseases and health problems. Obesity is clinically defined using Body Mass Index (BMI), which is calculated using a person’s height and weight. BMI provides a reliable indicator of body fat for most people.
Obesity is classified into 3 main classes:
- Class 1 obesity: BMI 30 to
- Class 2 obesity: BMI 35 to
- Class 3 obesity: BMI 40 or higher (also known as severe obesity)
This article will focus specifically on class 2 obesity, covering the definition, causes, health risks, diagnosis, and treatment options.
Definition of Class 2 Obesity
Class 2 obesity is defined as having a BMI of 35.0 to 39.9. To calculate BMI, divide weight in pounds (lbs) by height in inches (in) squared and multiply by a conversion factor of 703:
BMI = (Weight in Pounds / (Height in inches x Height in inches)) x 703
For example, a person who is 5’10” (70 inches) and 220 lbs would have a BMI of:
BMI = (220 lbs / (70 in x 70 in)) x 703 = 31.6
This would be classified as class 1 obesity. To reach class 2 obesity at this height, the person’s weight would need to increase to at least 246 lbs.
Some key facts about class 2 obesity:
- BMI 35.0 – 39.9
- Markedly obese
- Significantly increased health risks
Class 2 obesity is sometimes referred to as severe, morbid, or clinically significant obesity. It represents substantial excess weight that will almost always have negative effects on health.
Causes of Class 2 Obesity
Obesity occurs when a person’s energy intake exceeds the energy expended over time. There are many complex factors that influence energy balance and weight gain, including:
- Genetics – Some people inherit genes that predispose them to obesity.
- Lifestyle habits – Diet, physical activity level, sleep patterns and other behaviors affect weight.
- Medical conditions – Hormonal/metabolic disorders like hypothyroidism can lead to obesity.
- Medications – Some drugs like steroids, antidepressants may increase weight.
- Social/economic factors – Education, income, food environment, and culture influence obesity risk.
- Pregnancy – Gestational weight gain can contribute to long-term obesity.
In most cases of class 2 obesity, there are multiple contributing factors. People may have a genetic tendency towards obesity that is exacerbated by daily habits like overeating calorie-dense fast food, drinking sugary beverages, and getting little physical activity. Social and economic limitations can make maintaining a healthy lifestyle difficult for some people.
Health Risks of Class 2 Obesity
Class 2 obesity is associated with substantially elevated health risks compared to normal weight. Some conditions linked to class 2 obesity include:
- Type 2 diabetes
- High blood pressure
- High cholesterol
- Heart disease and stroke
- Gallbladder disease
- Gastroesophageal reflux disease (GERD)
- Osteoarthritis
- Sleep apnea and breathing disorders
- Some cancers (endometrial, breast, colon, etc.)
- Liver and kidney disease
- Mental health conditions like depression
- Reproductive health complications
- Increased surgical risks
- Premature death
The health risks rise progressively with increasing BMI. People with class 2 obesity have a significantly higher risk of developing obesity-related conditions than individuals with class 1 obesity. Their life expectancy is also considerably reduced compared to normal weight individuals.
Impact on Life Expectancy
One study found that having class 2 obesity at age 40 reduces life expectancy by about 7 years for men and 5 years for women compared to normal weight individuals. The more severe the obesity, the greater the reduction in life expectancy.
Losing weight can help prolong life expectancy. Even a modest 10% weight loss can have meaningful health benefits by lowering disease risks.
Diagnosis of Class 2 Obesity
Class 2 obesity is diagnosed when a person’s BMI reaches 35.0 to 39.9. A doctor will typically calculate BMI at an office visit and determine if a patient has class 2 obesity based on their height and current weight.
Additional assessments may include:
- Waist circumference measurement
- Body fat percentage estimate
- Medical history review
- Physical exam
- Lab tests to assess obesity-related conditions
These evaluations help determine overall health status and risks associated with excess weight. Doctors can then advise on weight management options to improve health.
Treatment for Class 2 Obesity
Treatment for class 2 obesity focuses on long-term lifestyle changes to achieve sustained weight loss and health improvements. Options may include:
Dietary Changes
- Following an evidence-based diet program like the Mediterranean diet or DASH diet
- Working with a dietitian to create a nutritious, calorie-controlled meal plan
- Joining a commercial weight loss program that provides diet guidance
- Keeping a food journal to increase awareness of eating habits
- Learning mindful eating practices
Increased Physical Activity
- Aim for 150-300 minutes per week of moderate exercise like brisk walking
- Incorporate strength training 2-3 times per week
- Add more movement throughout the day (take stairs, park farther away, etc.)
- Try higher intensity interval training if able
- Work with a personal trainer or take exercise classes if needed for motivation
Behavioral Strategies
- Attend individual or group therapy focused on changing eating patterns
- Practice stress management techniques
- Join a support group to help meet weight loss goals
- Limit screen time and get enough sleep
Medications
- Prescription weight loss medications like phentermine, Qsymia, Saxenda can help improve results when combined with lifestyle changes.
- Bariatric procedures may also be an option for some individuals with severe obesity.
A customized, comprehensive approach combining multiple interventions generally leads to the most success. Even losing 5-10% of initial body weight can significantly lower obesity-related disease risks.
Prevention of Class 2 Obesity
Preventing class 2 obesity centers around adopting long-term healthy lifestyle habits, including:
- Eating a nutritious, portion-controlled diet focused on whole foods like vegetables, fruits, lean proteins, whole grains, and healthy fats
- Engaging in regular physical activity and limiting sedentary time
- Weighing yourself weekly to catch weight gain early
- Getting enough sleep and managing stress
- Keeping refined carbs, added sugars, and unhealthy fats to a minimum
Other tips that may help prevent obesity progression include:
- Eating mindfully by paying attention to hunger/fullness cues
- Serving meals on smaller plates
- Chewing food thoroughly and eating slowly
- Meal planning and prep to control portions
- Limiting liquid calorie intake
- Seeking support and enlisting social contacts for motivation
Genetic factors play a key role in obesity risk, so prevention efforts should start early in life by establishing healthy family habits. Ongoing support and policy changes are also needed to promote affordable, accessible healthy food options and physical activity for everyone.
Outlook for Class 2 Obesity
With appropriate treatment, individuals with class 2 obesity can successfully lose weight and reduce associated health risks. However, managing obesity is a lifelong effort. Most people regain some weight over time and require ongoing focus on lifestyle habits to keep weight down.
On average, people who lose weight can expect to keep off about 10% of their body weight long-term. Even small amounts of weight loss of 5-10% can have meaningful health benefits.
Some tips for maintaining long-term weight management include:
- Continuing to monitor body weight weekly or monthly
- Being prepared for challenging life events that may impact habits
- Accepting small lapses and getting back on track quickly
- Having occasional more intensive weight loss efforts to counter gradual regain
- Making changes sustainable by allowing for flexibility and personal preferences
Maintaining as much weight loss as possible over time leads to better health outcomes. Partnering with healthcare providers knowledgeable about obesity can help provide ongoing support.
Conclusion
Class 2 obesity is defined as having a BMI of 35.0 to 39.9. It represents substantial excess weight that significantly raises risks for numerous diseases, health complications, and premature death. Treating class 2 obesity requires comprehensive lifestyle changes supported by healthcare professionals. With commitment to lifelong healthy habits, substantial improvements in health and wellbeing are possible.