In Western countries, people are considered obese when their body mass index (BMI) exceeds 30 kg/m2, with the range 25-30 kg/m2 defined as overweight. BMI is closely related to both percentage body fat and total body fat.

Obesity increases the likelihood  of various diseases , such as heart disease, diabetes and cancer, sleep apnea, along with other illnesses such as joint problems or high blood pressure. There are several factors contributing towards obesity and interaction between these factors is very complex. Obesity is most commonly caused by a combination of excessive  food energy intake, lack of physical activity, and genetic susceptibility, although a few cases are caused primarily by genes, endocrine disorders, medications, or psychiatric illness. Evidence to support the view that some obese people eat little yet gain weight due to a slow metabolism is limited. On average, obese people have a greater energy expenditure than their thin counterparts due to the energy required to maintain an increased body mass. Moreover, social, economic, environmental factors and behavioural factors are also contributing to obesity. For instance, sedentary lifestyle plays a significant role in obesity.

Associated Diseases

Heart disease, type 2 diabetes, high blood cholesterol, sleep apnea, certain types of cancer, asthma, stroke, migraines, and osteoarthritis. It can also lead to polycystic oavarian syndrome, menstrual disorders, infertility or erectile dysfunction. Binge eating disorder can increase obesity risk. In general, it can reduce life expectancy, lead to social stigmatizazion and it is considered to be a leading preventable causes of death.


Obesity can cause several complications including  breathlessness, difficulty doing any activity, increased level of exhaustion or low self-esteem.

Risk factors

  • genetics
  • family lifestyle
  • unhealthy diet
  • medications
  • physical inactivity
  • stress
  • age

Obesity leads to infertility in both men and women. This is primarily due to excess estrogen interfering with normal ovulation in women and altering spermatogenesis in men. It is believed to cause 6%of primary infertility. The most frequent anovulatory cycles are related to polycystic ovary syndrome (PCOS) occurrence, commonly associated with obesity and hormonal disturbances in the course of obesity. Obese women also have increased risk of preterm births and low birth weight infants. On top of that, women who are obese during pregnancy have a greater risk of having child malformations.

Obesity was also found to be associated with male infertility related to erectile dysfunction, hormonal disturbances and a reduction in sperm count and quality.The risk factors of male infertility include age, some chronic diseases, especially obesity and its related disorders as well as infectious diseases, use of some medications, environmental factors (lead, arsenic, aniline dyes, ionizing radiation, electromagnetic fields, exposure), and lifestyle factors (high-fat and high-caloric diet, low physical activity, smoking, drinking and drug use, as well as tight and plastic clothing)

It is well known that obesity is associated with erectile dysfunction. The risk factors of erectile dysfunction include obesity grade, visceral obesity, low testosterone level, and physical inactivity.

Obesity-related hormonal disturbances are not restricted to androgen deficiency. It was suggested that decreased sex hormone-binding globulin (SHBG) and increased free testosterone levels in consequence favor testosterone to estradiol conversion in adipose tissue. Decreased testosterone-to-estradiol ratio contributes to impaired spermatogenesis and infertility development.

Both obesity and infertility are the important risk factors of psychological disturbances and poor quality of life among women and men in reproductive age. On the other hand, the mood disorders may exacerbate the hormonal disturbances and worsen the effectiveness of infertility management.

Multiple reproductive dysfunctions have been associated with obesity including anovulation, and infertility. Obese patients undergoing IVF or intracytoplasmic sperm injection (ICSI) treatment are known to have increased FSH requirement, fewer collected oocytes, and frequent cycle cancellation, lower pregnancy rate and increase miscarriage rate than their non-obese counterpart.

Traditionally, obesity prevention is aimed at behavioural changes and lifestyle modification at a personal level and it is still the case today, leading to widespread stigma directed at obese individuals even by health professionals. Much time, money, and effort is risked into believing that obesity is a matter of personal responsibility while crucial opportunities to make key environmental changes and have a greater impact on obesity prevention are missed. The situation is further exacerbated by different concepts of obesity prevention made available to the obese person through public health authorities, the food and marketing industry, and, lastly, the government. Obese individuals are unable to make healthy choices when they are wrongly influenced towards unhealthy ones. Concerns have also been raised over the use of BMI as an obesity indicator. Much bias may arise due to BMI variations arising as a result of ethnicity, age, sex, and differences in body build.

People are considered obese when their BMI is 30 or higher.  

  • Any BMI ≥ 35 or40 kg/m2 is severe obesity.
  • A BMI of ≥35 kg/m2 and experiencing obesity-related health conditions or ≥40–44.9 kg/m2 is morbid obesity.
  • A BMI of ≥ 45 or50 kg/m2 is super obesity

Other symptoms are:

The main treatment for obesity consists of diet modification, lifestyle changes and doing physical exercise. Diet programs may produce weight loss over the short term, but maintaining this weight loss is frequently difficult and often requires making exercise and a lower calorie diet a permanent part of an individual's lifestyle. Dietary and lifestyle changes are effective in limiting excessive weight gain in pregnancy and improve outcomes for both the mother and the child.

With use, muscles consume energy derived from both fat and glycogen. Due to the large size of leg muscles, walking, running, and cycling are the most effective means of exercise to reduce body fat.


Also stress frequently triggers overeating which can lead to obesity. Psychological causes of stress eating and other types of emotional eating include poor awareness of internal physiological states and inability to differentiate between the hunger cues and emotional arousal. Some individuals are more susceptible to stress-induced eating than others and may adopt a self-regulation strategy for coping with aversive states in which attention is shifted away from negative self-appraisal or affect and towards the immediate stimulus environment, such as food.  Mindfulness-based intervention may be effective in reducing stress and improving stress-related overeating. Mindfulness training reduces psychological stress and enhances psychological well-being for a variety of health conditions, may improve cortisol patterns, may reduce binge eating and other eating disorder symptoms among patients with eating disorders, and may reduce weight among obese and non-obese adults. Besides that yoga, meditation and other mind-body therapies could help in treatment of obesity; nevertheless, more research need to be done on these form of therapies in treatment of obesity.


Three medications, orlistat (Xenical), lorcaserin (Belviq) and a combination of phentermine and topiramate (Qsymia) are currently available and have evidence for long term use. Weight loss with orlistat is modest, an average of 2.9 kg (6.4 lb) at 1 to 4 years. Its use is associated with high rates of gastrointestinal side effects and concerns have been raised about negative effects on the kidneys. The other two medications are available in the United States but not Europe. Lorcaserin results in an average 3.1 kg weight loss (3% of body weight) greater than placebo over a year; however, it may increase heart valve problems. A combination of phentermine and topiramate is also somewhat effective; however, it may be associated with heart problems. There is no information on how these drugs affect longer-term complications of obesity such as cardiovascular disease or death.

Surgical Therapy

Batriatric surgery

Bariatric surgery ("weight loss surgery") is the use of surgical intervention in the treatment of obesity. As every operation may have complications, surgery is only recommended for severely obese people (BMI > 40) who have failed to lose weight following dietary modification and pharmacological treatment. Weight loss surgery relies on various principles: the two most common approaches are reducing the volume of the stomach (e.g. by adjustable gastric banding and vertical banded gastroplasty), which produces an earlier sense of satiation, and reducing the length of bowel that comes into contact with food (gastric bypass surgery), which directly reduces absorption. Band surgery is reversible, while bowel shortening operations are not. Some procedures can be performed laparoscopically. Complications from weight loss surgery are frequent.

For patients who do not respond to diet, lifestyle modification, therapies, surgery and/or medication, in vitro fertilisation with ICSI can be performed. This usually includes controlled ovarian hyperstimulation with FSH injections, and oocyte release triggering with human chorionic gonadotropin (hCG) or a GnRH agonist. IVF- ICSI and other related ART fertilization techniques (IVF-PICSI, MACS etc.)  must be used  in the case of alteration of sperm values in obese men.
Severe cases of obesity are associated with unfavorable IVF/ICSI cycle outcome as evidenced by lower pregnancy rates.

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