What is obesity?

Obesity  is a chronic (long-term) medical disease of having too much body fat. Health care providers can diagnose obesity using a number called the body mass index (BMI). Your BMI is calculated from your current height and weight. For most people, the higher their BMI, the more body fat they have. A person may be considered to have overweight if their BMI is >25 kg/m2 and to have obesity if their BMI is >30 kg/m2. Some bodybuilders and athletes have high BMIs, but they have more muscle mass than average and are not considered to have obesity.

Why is obesity a concern?

About 30-40% or over 2.1 billion adults are estimated to have overweight or obesity. Both overweight and obesity can make it more likely that you will develop serious health complications. These problems include diabetes, high blood pressure, heart disease, stroke, fatty liver, sleep apnea, osteoarthritis, gallstones, high cholesterol, gout, and many types of cancer. Obesity can make many other medical problems harder to treat, lead to increased disability, and even raises the risk of early death.

Obesity is associated with stigma and can affect a person’s mental health and their ability to receive treatment.

What causes obesity?

Obesity is very complex and not just a simple problem of willpower or self-control. In general, it results from a combination of eating too much, getting too little physical activity, and genetics. Overweight or obesity occurs when, over time, the body takes in more calories than it burns. However, some people do gain weight more easily than others.

Another possible cause of obesity is a hormone imbalance, as in hypothyroidism (under active thyroid gland) or Cushing's syndrome. These are rare, though.

Some medications may cause weight gain, such as those used to treat diabetes, psychiatric illnesses, neurologic disorders, or inflammatory conditions. Your doctor may be able to suggest a different medication that has less effect on weight gain.

Our understanding of obesity is growing rapidly. For instance, we now know that fat cells, the gastrointestinal tract, and the brain produce many hormones that play an important role in how much you eat, how much energy (calories) you spend, and how much you will weigh.

Factors that Affect Obesity

Research shows that genetics have a role in obesity. Genes may have a strong role if you had difficulty managing weight throughout your life or if several of your blood relatives are significantly overweight. Studies show that people with a genetic predisposition to obesity may not be able to easily lose weight with traditional forms of diet and exercise. People who are genetically predisposed to obesity may require bariatric surgery to assist in weight management.

Your environment can also influence weight management. Environmental factors can start as early as before birth. Research shows that pregnant mothers who smoke or who have overweight or obesity are more likely to have children who have overweight or obesity as well. Neighborhoods, school systems, workplaces, income, media, and access to health care and healthy foods can all influence health decisions. It is important to create thriving environments to make it easier to engage in physical activity and healthy eating.

Stress and other psycho-social factors
Stress and a lack of sleep can also lead to obesity. Studies have shown that some people are more likely to overeat when affected by mental health issues such as depression, anxiety, or other emotions. A lack of sleep can disrupt ghrelin and leptin, which may cause obesity. People who are sleep-deprived may be less motivated to exercise, which leads to less calories burned.

How is obesity treated?

There is no simple solution or a pill to cure obesity. However, there are effective treatments to help manage it. Obesity needs a long-term approach that combines diet, increased activity, and behavioral changes.

Following various nutrition programs such as the Mediterranean, DASH or portion-controlled diets can help you lose weight and stay healthy. A dietitian may be able to help you meet your weight goals. 
Participating in moderate to physical activity most days of the week together with strengthening exercises can help you lose weight when combined with diet and is very important in maintaining weight loss. Reducing activities that mainly involve sitting, such as screen time or driving, can also be beneficial.

Weight loss medications can also be helpful for some people and your doctor may recommend a drug for you, such as orlistat, liraglutide, lorcaserin, or combination medications such as phentermine-topiramate and naltrexone-bupropion. You will have to stay on these medications in order to keep the weight off.

Some people with obesity may also benefit from bariatric (weight loss) surgery. Gastric bypass and  sleeve gastrectomy are the forms of surgery most commonly used nowadays and they are both very effective. 

Some people with health problems such as diabetes may need to be under a doctor’s care while they lose weight. They also may need a physical exam before they begin physical activity.

Endocrinologists, who are specialists in hormones and metabolism, can help assess the cause of your obesity and the possible complications. They also can direct how you should be treated and prescribe and monitor your medications.

Don’t expect overnight results with a weight loss plan. There are no quick fixes. Weight loss takes time. To keep the weight off, you will need to make any changes in diet and activity a part of your routine for the rest of your life. Modifying your daily habits can be difficult at first. Start with small and measurable weekly goals to reach. Achieving a 5-10% loss in your weight can make a big difference in your risk for complications associated with obesity. 

What can you do to lose weight?

  • Lifestyle Changes: Reduce intake of foods that are high in fat or sugar. 

  • Eat more fruits, vegetables, and whole grains.

  • Spend 30 minutes a day in moderate physical activity (such as brisk walking).

  • Eat three meals each day, including breakfast.

  • Control portions of meals and snacks.

  • Find ways to be more physically active. For instance, take the stairs whenever possible or park your car farther out in the parking lot.

  • Get your household members involved to make changes sustainable.

Questions to ask your doctor

  • Do I need to lose weight?
  • What is the healthiest way for me to start losing weight?
  • How much weight should I try to lose each week?
  • What physical activity is safe for me?
  • Are there any hormonal conditions that can be causing the weight gain?
  • Are there any medications I am on that can be causing the weight gain?
  • What weight loss treatment options are best for me?
  • What are the risks and benefits of each of these treatment options?
  • Are weight loss medications or bariatric surgery an option for me?
  • Should I see a registered dietitian? Should I see an endocrinologist?
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