Definition of Obesity and Overweight: What is Obesity?

Obesity has been arbitrarily interchanged with overweight. However, at the medical point of view they are supposed to be defined differently. The term obesity refers to the medical condition where there is an accumulation of excess body fat. Being overweight may refer to the inappropriate or too much weight for one’s height. Additionally, being overweight may due to other structures in the body such as the muscle and the bone rather than fats.

Overweight Woman Body Fat Measurement

Overweight can also be a “pre-obesity” stage in a standard classification, but the risks of associated diseases increase as an individual became categorized as obese. The excess fat build-up associated with obesity may cause adverse health effects where in many cases can lead to other metabolic, cardiovascular and respiratory diseases. Thus, obesity may reduce the life expectancy of an individual.

To further define obesity, a crude population measure known as the body mass index (BMI) is used. It is done by comparing weight with height and by a standard table, the level of obesity can be determined.

Here Is the Formula for Calculating BMI:

[box type=”important”]BMI = weight in kilograms ÷ height in meters2[/box]

The BMI of an individual is correlated to the total body fat and percentage body fat. The result of one’s BMI is categorized and classified using the standard table below:

 BMI Classification

<18.5 Underweight
18.5 – 24.9 Normal weight
25 – 29.9 Overweight
30 – 34.9 Class I obesity
35 – 39.9 Class II obesity
>40 Class III obesity


Further classification of class III obesity has been broken down into categories, though the exact values remain under investigation.

Class III Obesity

Any >35 or 40 Severe obesity
A BMI of >35 or 40-44.9 or 49.9 Morbid obesity
A BMI of >45 or 50 Super obesity

The fat distribution of an individual can also be assessed using the waist-hip ratio (WHR). In WHR, the body fat distribution determines the associated risk for health problems such as diabetes, hypertension and coronary heart disease. Below is a chart that determines the body fat distribution according waist-hip ratio and their associated health risks.

Waist-Hip Ratio Vs. Health Risk

MALE FEMALE Health Risk Based Solely on WHR
0.95 or below 0.80 or below Low risk
0.96 to 1.0 0.81 to 0.85 Moderate Risk
1.0+ 0.85+ High Risk

To measure waist-hip ratio, the waist circumference at a level midway between the lowest rib and the iliac crest is determined. Then, the hip circumference at the level of the great trochanters with the legs close together is determined. The waist circumference is divided by the hip circumference and equals to waist-hip ratio.

The Health Risks of Obesity

While a lot of people may have considered obesity to be just disfiguring cosmetic issue, the real problem of being obese is the risks it poses on one’s health. As mentioned earlier, there are other diseases directly associated with obesity.

[box type=”important”]These diseases cause approximately 300,000 deaths annually in the US alone. It has also been observed that the life expectancy of people with BMI over 40 is significantly reduced.[/box]

Chronic Diseases Associated with Obesity:

  • Diabetes – the adult onset or type 2 diabetes mellitus
  • Hypercholesterolemia – or high cholesterol levels in the blood
  • Hypertension – also known as high blood pressure
  • Cerborvascular accident – or stroke
  • Coronary heart disease – or cholesterol build up in the blood vessels of the heart
  • Insulin resistance – insulin maintains the normal blood glucose levels. In this disease, the effectiveness of insulin is diminished. It is also a pre-diabetes condition.
  • Congestive heart failure
  • Osteoarthritis – inflammation of the joints, due to pressure points from excessive weight
  • Gallstones
  • Gout
  • Sleep apnea
  • Cancer – though inconclusive, studies have shown that obesity is associated with colon cancer, rectal cancer, prostate cancer, cancer of the gallbladder, cancer of the uterus, and breast cancer.

[box type=”important”]To read more about Natural Remedies for Gout, follow the link.  [/box]


The Causes of Obesity

Obesity may root from both lifestyle and genetics. It is usually the interplay of the two factors that bring about the excessive fat gain; thus, obesity. An individual usually eat more than his/her body needs, exercise less, and practice a sedentary lifestyle. The metabolism of a person greatly adds to the factors to be considered. A person who eats more and acquire more calories than he can metabolize, will gain stored energy. Our body stores calories as fats. Additionally, if a person is genetically predisposed to having a heavy built, he/she can likely to become obese. To sum it up, hereditary predisposition together with overeating and less physical activity are the main causes of obesity.

Other causes of obesity can be due to certain organic diseases, such as hypothyroidism, Cushing’s syndrome, polycystic ovary syndrome, and insulin resistance.

Medications Associated with Obesity

Certain medication can also be associated with obesity and weight gain. Among these drugs include: antidepressants, anti-seizure such as Carbamazepine and Valproate, hypoglycemic (drugs that lower blood sugar) such as Sulfonylureas, certain oral contraceptives, corticosteroids such as Prednisone, certain anti-hypertensive drugs and antihistamines.  Other medication that can cause significant weight gain include antipsychotic drugs which are used for people with Schizophrenia or Bipolar disorder such as Olanzapine, Clozapine, and Risperdal.

Gender-wise, women are more prone to become obese than men. The fat distribution among women is more prominent than among men; and women are less muscular than men. The muscles greatly help in burning calories than any other tissues in the body, that’s why men have this advantage over women. Moreover, the hormones of pregnancy and the use of oral contraceptives in women add to the factors of weight gain.

Ethnicity also has its bearing on obesity. It has been observed that African American women and Hispanic women are more prone to experience weight gain earlier in life than Asians and Caucasians. On the other hand, Hispanic men are observed to be obese earlier in life than Caucasian and African American men.

Treatments for Obesity

Although dieting and physical exercise are the most obvious remedy to obesity, other weight loss programs are now being practiced alongside with medical treatments. One of the most popular medications that is approved for long term use and currently widely available is Orlistat. Diet programs create a short term effect on weight loss unless they are successfully combined with religious exercise and medical regimen. The desired results usually take longer than expected to some, if not most, obese people.

Bariatirc surgery or weight loss surgery is considered the most effective treatment for obesity. The objective of bariatrics is long-term weight loss and decreased overall mortality. There are different techniques available to provide the best results. This procedure is combined with a program that consists of dieting, exercise and regular follow-ups with the surgeon. Though quite costly, the desired result is achievable in a much shorter period of time compared to the usual diet-exercise-medical regimen. The associated risks are minimized when the best bariatric technique is chosen and the entire bariatric program is adhered to accordingly.

Preventing Obesity

Since most of the causes are associated with eating habits and lack of exercise, lifestyle modification considerably help in the prevention of obesity. People with much associated risk factors can start following a healthy way of living by exercise and dieting. The ideal body weight should be maintained in order to avoid getting into the “overweight” bracket that is considered to be a prelude to obesity.

The prevention is not a short term fix but should be observed as a life-long process. Avoiding unhealthy foods and throwing away a sedentary lifestyle can greatly add to the prevention of obesity. The goal of maintaining the ideal body weight should always be kept in mind. There should be an inner determination to get away from gaining unnecessary weight in order to totally prevent obesity and live a more healthy and productive life.


We are the content managers of, a weight loss surgery resource. We help patients through the enormous process of undergoing bariatric surgery.

7 thoughts on “Definition of Obesity and Overweight: What is Obesity?

  • December 5, 2011 at 2:53 am

    Thanks for making us understand this classification about obesity.This classification should be made official & data should be shared with the people so that they will understand on what level we are & will show their effort in controlling obesity.

  • August 19, 2011 at 9:16 am

    Thanks for this very informative post. The rise in obesity, particularly amongst young people, is alarming and something I have campaigned against for a long time. I believe that a good diet and exercise in moderation is the best way to combat this plague in society, but it requires education to get the massage across.

  • March 28, 2011 at 9:33 am

    During the course of my research, I’ve found that there’s two main villains causing overweight and obesity problems. They are: poor diets / food choices and a lack of physical activity. Sadly, I’ve found research that suggests children and preteen adolescents are eating more food away from the home, snacking more habitually on junk food, and drinking more sugar-sweetened beverages. Convenience has become a major theme for our food choices today, thus leading more of us to consume fast food, restaurant meals, or cheap prepackaged meals to prepare in the microwave. Did you know that only 21 percent of young people eat the recommended five or more servings of fruits and vegetables each day? (Centers for Disease Control and Prevention. (2004). Physical activity and good nutrition essential elements to preventing chronic disease and obesity.) Also, nearly half of all vegetable servings consumed by children are fried potatoes (aka french fries!!!) To a large extent, these choices frequently contain substandard nutritional value for the human body. In order to win the war on childhood obesity, families need to cook healthy, fresh, nutritious meals at home, have healthy snacks on hand, and also find fun activities to do as a family like bike riding, hiking, walking, golf, swimming, playing catch, skateboarding, etc. – Anything to stay active and away from the couch.
    If you or someone you love needs help for obesity, please contact your physician and make a plan of action to improve your health.

  • March 22, 2011 at 2:14 pm

    It’s quite clear that obesity is out of control. It’s a modern plague and in 20 years or so we’ll see how much it hurts us as a complete society.

  • March 10, 2011 at 5:12 am

    I definitely agree that obesity is a huge issue today (no pun intended). However, I also think that certain issues can assist in overweight and obesity that go undiagnosed. I was diagnosed with Celiac Disease about two years ago, but until then, I could never lose weight no matter what I tried. After cutting gluten out of my diet, inside a month I lost 30 pounds without even trying.


  • March 7, 2011 at 11:25 am

    Obesity is a huge problem today. People really need to exercise daily and learn that there are plenty of unhealthy foods that should be avoided instead of eating them in moderation.

  • March 3, 2011 at 7:22 pm

    yes…Obesity can occur at any age, lifestyle and eating habits are things that can aggravate this situation.


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