Obesity is the excessive accumulation of fat in the body. Though obesity cannot be considered dangerous on its own, it has been attributed to the development of various chronic health conditions over time.
Obesity and BMIBasal Metabolic Index (BMI) is the measure of your body fat in comparison to your height. It helps screen people to various weight categories which may make the person susceptible to certain diseases.
For an adult, obesity is defined as a BMI of 30 or higher (normal range 18.5 – 24.9). The worldwide incidences of obesity are on the rise and its cases have increased by over 3 times worldwide in the last 3 decades. It is a common health problem in the United States.
In children and adolescents, obesity is defined as weight for height greater than 3SD and 2 SD above the WHO-defined growth reference median. Age is an important factor in determining obesity in children.
Complications of ObesityAs mentioned earlier obesity is not dangerous just on its own but it can lead to long term health complications, which includes:
- Type-2 Diabetes
- High blood pressure
- Coronary artery disease
- Fatty changes of the liver and the gallbladder
Causes of ObesityTechnically, obesity is caused as a result of not burning enough of the calories through daily activities that you take in through your diet. These calories add up over time and lead to weight gain. Leading a sedentary life considerably increases the risk of obesity.
The cause of obesity however is not limited only to calories and lifestyle, it is a complex multifactorial condition influenced by genetics and other socio-cultural factors. These may include:
- Hereditary: Results of various studies have shown obesity to be a very heritable condition. Various genes have been identified that controls how your body processes and stores energy obtained from food.
- Aging: Slowing of metabolism as one ages, leads to a decrease in energy output and calorie excess; as a result, more weight gain is seen in the older population.
- Insomnia: Lack of adequate sleep has been shown to cause an increased craving for food due to hormonal imbalances.
- Endocrine disorders: Various diseases of the endocrine system (system controlling the levels and processes of hormones in the body) have shown to lead to obesity. Some of which are Cushing syndrome (excess cortisol hormone), polycystic ovarian syndrome (imbalance in levels of female reproductive hormones), and hypothyroidism (low thyroid hormone level). The mechanism of causation of obesity is different for different endocrine disorders.
- Depression: Depression may lead to weight gain when patients turn to food to relieve them of emotional difficulties. Also, patients undergoing drug therapy for depression may experience weight gain, as weight gain is a known complication of many first-line drugs of depression.
- Poverty: Poverty can lead to obesity due to higher unemployment, lower education, and less access to fitness activities.
- Education: Adults who have not completed high school have the highest rate of obesity, while college graduates have the lowest.
Diagnosing ObesityMeasuring BMI is a standard tool in diagnosing obesity. Other simple methods of measuring body fat include:
- Skinfold thickness: The thickness of fat just beneath the skin is measured from different parts of the body using a device called the caliper. The measurement helps assess body fat percentage.
- Waist: Hip ratio: It is calculated using a simple measuring tape. The ratio of more than 1 in males and 0.8 in females is considered significant for obesity.
In addition to these commonly performed tests CT, MRI, Bioelectric impedance analysis, DEXA scan, and air densitometry can also be done.
Your doctor may advise blood tests, kidney function tests, liver function tests, lipid profile, thyroid hormone levels, vitamin D levels, urine analysis, ECG or sleep studies to rule out and evaluate for the presence of other associated comorbidities.
Managing ObesityThe treatment of obesity is highly individualized and focuses on treating the underlying cause and treating associated comorbidities. Treating obesity may require diet and behavior modifications, medications, or even surgery.
- Diet and behavior modification: A diet low in calories is recommended, along with constant monitoring for weight loss. Intense behavioral interventions in the form of cognitive-behavioral therapy and interpersonal psychotherapy may be required to motivate obese people to change high-risk behaviors. Combining behavioral therapy with diet and exercises has shown to be effective in bringing lifestyle changes in the patients.
- Medications: Medications are used in cases where the BMI is greater or equal to 30. FDA-approved drugs for long-term management of obesity include Orlistat, phentermine, diethylpropion among others. These drugs work by decreasing food absorption or by reducing appetite. Orlistat is generally the drug of choice owing to the presence of fewer side effects.
- Surgery: Bariatric surgery is weight loss surgery done to make the stomach smaller. It is usually reserved for patients with a BMI of 35 or over or in obese patients with considerable health problems.
Recent Advances and Clinical TrialsIndividual Drug therapy: A study is being carried out to determine the best medication for a certain phenotype. The study assesses the efficacy of FDA-approved medications in treating obesity in different phenotypes and helps select the best medication for individual phenotypes. It is currently in Phase-3 of the clinical trial.
Phentermine-Topiramate Extended-Release drugs: The efficacy of anti-obesity drug Phentermine-Topiramate in extended-release forms is being assessed in treating obesity in comparison with a placebo. The patients in the clinical trial will be provided with an activity tracker and lifestyle intervention methods. It is currently in Phase-4 of the clinical trial.
Liraglutide: Liraglutide is an FDA approved anti-obesity medication. A clinical trial is currently underway to assess the efficacy of 3 grams liraglutide in stomach emptying, and reducing obesity compared to placebo therapy. It is currently in phase-2 of its clinical trial.
Acetaminophen Dosing in childhood obesity: Acetaminophen is a commonly used medicine in the pediatric population. Multiple studies are assessing the pharmacokinetics of acetaminophen in normal populations but none in the obese population. A study is currently underway that aims to assess optimal dosing of acetaminophen in obese children and adolescents to produce desired effects. It is currently in Phase-3 of the clinical trial.
Sleep restriction in obesity: Insufficient sleep is thought to be a preventable cause of obesity. A clinical trial is currently underway to assess the effects of sleep restriction in obesity and devise methods to reduce associated risks.
Kiran K. Panuganti, Minhthao Nguyen, Ravi K. Kshirsagar. Obesity. StatPearls Publishing; 2020 Jan-.