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Obesity : Classification, Causes, Complications, Treatment- Diet Control, Medications, Exercises, Surgery

What is Obesity?

Obesity is a metabolic disorder resulting in excess body fat deposits in subcutaneous (under the skin) tissue. The layer of body fat is also known as adipose tissue. Fatty cells and lipid deposits lies within fatty or adipose tissue. Adipose tissue is made up of lipids, connective tissue, capillaries, blood vessels and adipose cells. Adipose cells store energy in the form of lipid, which lies in connective tissue surrounded by adipose cells.


Classification of Obesity

Obesity is classified as obesity class 1 to class 3 when BMI is increased from 25 to 40. Obesity is also known as morbid or super morbid obesity when BMI is higher than 40. Classification of obesity depends on amount of lipid deposited in connective tissue all over the body. Obesity is counted as Body Mass Index. Body Mass Index (BMI) is calculated as a ratio of weight in Kg and Height in meter.

  • BMI (Kg/m2) = Weight in Kg/Height in meter.
  • Normal BMI- 19 to 25
  • Underweight BMI- less than 19
  • Overweight- 25 to 29
  • Obesity Class I – 29.1 to 35
  • Obesity Class II – 35.1 to 40
  • Obesity Class III – 40.1 and above
    1. Morbid Obesity- 40 to 45
    2. Super Obesity- 45 to 50

Causes of Obesity

Obesity is caused by energy imbalance resulting from eating more than needed or inactive life style. The causes are as follows-

A. Energy Imbalance- Metabolism of carbohydrate and fat results in production of energy, which helps to maintain normal body temperature and various cellular functions. Unused fat is stored for emergency use as an adipose or fatty tissue. The stored fat is used and replaced. Adipose or fatty tissue becomes denser when consumption of stored fat is less than the fat deposited in fatty tissue. Energy imbalance results when less amount of deposited fat is consumed and simultaneously excess fat is stored in connective or adipose tissue. In addition surplus carbohydrate is converted and stored as glycogen and fat for future use. Causes of energy imbalance are as follows-

a. Too Much Food or Calories

  • Sweet drinks- Intake of food and drinks containing high concentration of sugar promote fat deposits in connective tissue. Surplus sugar is converted to fat.
  • French Fries- French fry contains fat plus carbohydrate. Fat comes from absorption of oil, which is used to fry the sliced potatoes.
  • Junk Food- Junk food is minced food that contains high fat concentration from minced animal guts and fat.
  • Processed Food- Processed foods are made of starch or carbohydrate. Most of the processed food are fried and stored in dry form.
  • Night Eating- Sleeping late and sleeping less, results in frequent intake of food. Small portion may cause less harm than large portions. Intake of frequent processed food results in intake of excess carbohydrate and fat, which eventually is stored as adipose or fatty tissue.

b. Less Vegetables

  • Vegetables bring volume in consumed food. Full stomach suppresses appetite. Vegetable diet fills stomach and reduces appetite. Exclusion or minimum intake of vegetables increases appetite. Volume of meal to be filled by vegetables is now replaced by food containing carbohydrate or fat resulting in increased absorption and deposits of additional fat in adipose tissue.

c. Less Activities

  • Inactive life style results in production of less energy and burning of less fat. Less active life style also presents more idle time, which is often used for munching small or large portion of tasty sweet food containing fat and carbohydrate.
  • Reasons for less active life style are as follows-
  1. Sedentary life style.
  2. Disability.
  3. Pain following injury.
  4. Severe cold or hot weather.

B. Genetic Susceptibility Causes of Obesity

Abnormalities of gene and gene expression can influence appetite, metabolism and endocrinal hormone secretions resulting in obesity.
Examples of changes in gene expression are as follows-

  • Polymorphism of gene controlling appetite- increased appetite.
  • Polymorphism of gene controlling metabolism- decreased metabolism.
  • Polymorphism of gene controlling endocrinal secretions- Increased or decreased secretions of hormones resulting in obesity.

C. Medications Triggering Obesity

Following medications causes obesity-

  • Insulin
  • Sulfonylureas
  • Steroids
  • Antidepressants
  • Anticonvulsants
  • Estrogens

Complications Of Obesity

Obesity results in following complications and diseases.

A. Endocrine Disorder 2

  • Parathyroidism- Increased parathyroid hormone
  • Hypothyroidism– Low thyroid hormone.
  • Cushing Syndrome– Results following exposure of body to increased secretion of corticosteroid hormones.
  • Growth Hormone Deficiency- Growth hormone secretion is significantly reduced.
  • Testosterone Deficiency- Less secretion of testosterone hormones.

B. Metabolic Disorder

  • Diabetes– Obesity alters response to insulin resulting in increase of blood sugar and symptoms of diabetes.
  • Increases Cholesterol- Obesity interferes with liver metabolism of fat and causes increased cholesterol in blood.
  • High Triglycerides- Triglyceride level is higher in patients suffering with obesity.

C. Cardiac Disease

Following cardiac diseases are caused by obesity:

  • Hypertension
  • Cardiomegaly
  • Congestive Heart Failure

D. Respiratory Disease

Following respiratory diseases are associated with obesity.

E. Vascular Disease

Obesity causes peripheral vascular disease and deep vein thrombosis (DVT).

F. Psychiatric Illness

Following psychiatric diseases are caused by obesity

  • Anxiety
  • Depression
  • Social Stigma

Obesity Related Diseases

Following diseases are directly caused by obesity:

Life Expectancy- Obesity Reduces Life Expectancy

Treatment for Obesity

Treatment for Obesity

Diabetes is one of the most difficult illnesses to treat effectively with one treatment. Multiple treatments may be necessary. Choices of treatment are as follows-

Diet Control Treatment for Obesity

  • Less Sugar
  • Less Carbohydrate
  • Less Fat
  • Less Junk Food
  • More Fiber Diet
  • More Vegetables

Medication Treatment for Obesity

Anti Obesity Drugs

  • Better results are seen with Qsymia ( Phentermine + Topiramate)
  • Other anti obesity medications- Xenical (Orlistat) and Belviq (Lorcaserin)

Side Effects-

  • Gastrointestinal Side Effects- Nausea, vomiting and diarrhea
  • Kidney Effects- Increased BUN
  • Cardiovascular Effects- Abnormal heart valve function.

Exercises for Obesity

  • Exercise at Gym under supervision
  • Daily outdoor exercises like walking, jogging and garden work
  • Daily indoor exercises at home

Surgery for Obesity

  • Balloon
  • Bariatric Surgery
  • Long term weight loss is observed 2
  • Weight loss up to 25%3
  • Complications- 17% Cases 3

Advantage of Weight Loss-

  • Recovery from diabetes
  • Improvement of cardiac function
  • Reversal of hypertension to normal blood pressure

Also Read:


  1. Persons successful at long-term weight loss and maintenance continue to consume a low-energy, low-fat diet”. Shick SM, Wing RR, Klem ML, McGuire MT, Hill JO, Seagle H (April 1998). ” J Am Diet Assoc 98 (4): 408–13.
  2. “The Effectiveness and Risks of Bariatric Surgery”. Chang, Su-Hsin, Stoll, Carolyn R. T., Song, Jihyun et al., 18 December 2013JAMA Surgery.
  3. “Effects of bariatric surgery on mortality in Swedish obese subjects”. Sjöström L, Narbro K, Sjöström CD et al. (August 2007). N. Engl. J. Med. 357 (8): 741–52.
  4. Safety and effectiveness of the intragastric balloon for obesity. A meta-analysis. Imaz, I, Martínez-Cervell, C, García-Alvarez, EE et al. (July 2008). ” Obes Surg 18 (7): 841–6.
  5. Increases in morbid obesity in the USA: 2000- 2005 Sturm R (July 2007. Public Health 121 (7): 492–6.
  6. Use of relative weight and Body Mass Index for the determination of adiposity. Gray, DS, Fujioka, K (1991). ” J Clin Epidemiol 44 (6): 545–50.
  7. Body mass Index and mortality among 1.46 million white adults. Berrington de Gonzalez A (December 2010). N. Engl. J. Med. 363 (23): 2211–9.
  8. Body- Mass Index and mortality in a prospective cohort of US adults. Calle, EE, Thun, MJ, Petrelli, JM et al. (October 1999N. Engl. J. Med. 341 (15): 1097–105.
  9. Grundy SM (2004). “Obesity, metabolic syndrome, and cardiovascular disease”. J. Clin. Endocrinol. Metab. 89 (6): 2595–600.
  10. Z. Obesity and endocrine disease. Kokkoris P1, Pi-Sunyer FX., Endocrinol Metab Clin North Am. 2003 Dec;32(4):895-914.
Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:July 14, 2023

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