Obesity

Obesity is defined by having an excessive amount of body fat in an individual. A formula based on body height and weight -called the body mass index (BMI) – is normally used to determine if a person is obese or not. A BMI between 25-30 kg /m2 is considered overweight (or pre-obese); a BMI between 30-40 kg/m2 is considered obese; and a BMI 40 kg/m2 or greater is considered morbidly obese. Obesity occurs when a person eats and drinks more calorie than burns it on daily activities such as maintaining a baseline body metabolism and exercise. The extra calories are converted to fat and stored. Obesity is more than just a cosmetic concern; it increases the likelihood of various diseases, particularly cardiovascular disease, type 2 diabetes, obstructive sleep apnea, osteoarthritis and certain types of cancer.

BMI Calculator

The World Health Organization (WHO) predicts that overweight and obesity may soon replace more traditional public health concerns such as under nutrition and infectious diseases as the most significant cause of poor health.

What cause obesity?

The fundamental cause of obesity is body energy surplus: if the calories a person takes in are not completely used, it will be stored as fat.  When the fat accumulates to a certain point, overweight, then obesity develops.

In dealing with body energy surplus, individual differences do exist. For some people, it is especially hard to keep the weight off.  For people who live in the same place and eat the same foods, some become overweight and obese while others do not. Human bodies have a complex system to help keep weight at a healthy level. In some people, this system doesn’t seem to work well. This is because obesity is the result of interplay between genetic and environmental factors.

Variations in genes controlling appetite and metabolism predispose some people to higher risk for obesity. A person’s genes affect food preference and eating behaviors. For example, some people with certain genetic variants naturally prefer to energy-dense foods and others have diminished satiety. Genetics also determines the metabolism such as how body converts food into energy and how calories are consumed during exercise. The amount and the location where the storage fat will be distributed are also controlled by genes. Many genes associated with obesity have been identified.

Life style is another important factor that contributes to obesity.  When live in an environment surrounded by highly processed foods and constantly bombarded by ads for them, over eating became epidemic. In addition to the excess calorie intake, relaying on car for transportation, staying longer time in front of computer and TV screens led to much less calorie expenditure. Overeating and insufficient physical activity ultimately make people gain more weight.

Genetics aside, obesity can be caused by:

• Eating more food than your body can use
• Drinking too much alcohol (alcohol is very high in calories)
• Not getting enough exercise
• Certain medical problems or treatments including:
• Underactive thyroid gland (hypothyroidism)
• Taking medicines such as antidepressants, antipsychotics, diabetes medications, steroids, beta blockers and birth control pills.
• Other situations including:
• Quitting smoking
• Stress, anxiety, feeling sad, or not sleeping well can lead to overeating and weight gain
• For women, during menopause or not losing the weight gained during pregnancy

Health risks of obesity

Obesity is a major health threat. The extra weight puts added stress on every part of your body.
People with obesity are at increased risk to develop a number of potentially serious health problems, including:

• High cholesterol and triglycerides
• Type 2 diabetes
• High blood pressure
• Metabolic syndrome - a combination of high blood sugar, high blood pressure, high triglycerides and high cholesterol
• Heart disease
• Stroke
• Cancer, including cancer of the uterus, cervix, ovaries, breast, colon, rectum and prostate
• Sleep apnea
• Gallbladder disease
• Gynecologic problems, such as infertility and irregular periods
• Nonalcoholic fatty liver disease
• Osteoarthritis
• Skin problems, such as poor wound healing

In addition, obesity may cause depression, disability, physical discomfort, sexual problems, shame and social isolation.

Dieting and physical exercise are the mainstays of treatment for obesity. Weight loss programs often promote lifestyle changes and diet modification. This may involve eating smaller meals, improving diet quality by reducing the consumption of energy-dense foods such as those high in fat and sugars, and by increasing the intake of dietary fiber, making a conscious effort to exercise more.

When it comes to maintaining a healthy weight for a lifetime, the bottom line is – calories count! Weight management is all about balance – balancing the number of calories you consume with the number of calories your body uses or "burns off". When energy intake from foods is less than the energy expenditure from excises and normal activities, creating a calorie deficit, you lose weight. However, extreme diets (fewer than 1,100 calories per day) are not safe or to work very well. Most people who lose weight through extreme diet return to overeating and become obese again.

Calculate your Recommended Daily Calorie and see how many calories you can burn through various Physical Activities.

In general, eating more fruits and vegetables and less high energy density foods, drinking water instead of sugared drinks, being more physically active, reducing time sitting in front of a screen (TV, computer and video games) all help to keep weight off. 

It is well known that some people respond well to low fat diets while others benefit more from high fat diets.  What the best diet is for you depends on your genetic makeup. If you know your genetic profile of the obesity related genes, you may want to try a personalized diet regimens designed at GB Lifesciences.

If weight loss goals are not achieved by dietary and physical exercise approaches, anti-obesity drugs may be taken to reduce appetite or inhibit fat absorption.  In severe cases, surgery is performed or an intragastric balloon is placed to reduce stomach volume and/or bowel length, leading to earlier satiation and reduced ability to absorb nutrients from food.

In a clinical practice guideline by the American College of Physicians, the following five recommendations are made:

• People with a BMI of over 30 should be counseled on diet, exercise and other relevant behavioral interventions, and set a realistic goal for weight loss.
• If these goals are not achieved, pharmacotherapy can be offered. The person needs to be informed of the possibility of side-effects and the unavailability of long-term safety and efficacy data.
• Drug therapy may consist of sibutramine, orlistat, phentermine, diethylpropion, fluoxetine, and bupropion. For more severe cases of obesity, stronger drugs such as amphetamine and methamphetamine may be used on a selective basis. Evidence is not sufficient to recommend sertraline, topiramate, or zonisamide.
• In people with a BMI over 40 who fail to achieve their weight loss goals (with or without medication) and who develop obesity-related complications, referral for bariatric surgery may be indicated. The person needs to be aware of the potential complications.
• Those requiring bariatric surgery should be referred to high-volume referral centers, as the evidence suggests that surgeons who frequently perform these procedures have fewer complications.

Obesity costs about $150 billion a year in United States, or almost 10 percent of the national medical budget. Approximately one in three adults and one in six children are obese. Obesity is epidemic in the United States today. Obesity rate has dramatically increased in past three decades. 

Although obesity has strong genetic determinants, the genetic composition of the population does not change rapidly. Therefore, the dramatic increase in the prevalence of obesity must reflect major changes in environmental factors.

Learn obesity epidemic and steps to take to reduce or prevent obesity.