Genetics

Obesity is the result of interplay between genetic and environmental factors. Studies that have focused on inheritance patterns rather than on specific genes have found that 80% of the offspring of two obese parents were also obese, in contrast to less than 10% of the offspring of two parents who were of normal weight. Different people exposed to the same environment have different risks of obesity due to their underlying genetics.

ByPass Surgery Diet

To be a By pass Surgery  viable candidate, you should also be ready to re-learn your dietary habits. New dietary habits can help ensure the surgery has positive and lifelong effects. Before your surgery, you need to make plans for a special diet to follow both pre- and post-surgery. The pre-surgery diet is geared toward reducing the amount of fat in and around your liver. This reduces the risk of complications during the surgery. After the surgery, your doctor will tailor the general diet guidelines for you. The post-surgery diet usually consists of several weekly phases. It helps you recover, meet the needs of your now smaller stomach, and gain healthier eating habits.

Psychiatric Disorders

The risk of overweight and obesity is higher in patients with psychiatric disorders than in persons without psychiatric disorders. Certain medications may cause weight gain or changes in body composition; these include insulin, sulfonylureas, thiazolidinediones, atypical antipsychotics, antidepressants, steroids.Certain anticonvulsants (phenytoin and valproate), pizotifen, and some forms of hormonal contraception.

Gut Bacteria

Gut Bacteria is the study of the effect of infectious agents on metabolism is still in its early stages. Gut flora has been shown to differ between lean and obese people. There is an indication that gut flora can affect the metabolic potential. This apparent alteration is believed to confer a greater capacity to harvest energy contributing to obesity. Whether these differences are the direct cause or the result of obesity has yet to be determined unequivocally. The use of antibiotics among children has also been associated with obesity later in life.

Sedentary Lifestyle

A sedentary lifestyle plays a significant role in obesity. Worldwide there has been a large shift towards less physically demanding work, and currently at least 30% of the world's population gets insufficient exercise. This is primarily due to increasing use of mechanized transportation and a greater prevalence of labor-saving technology in the home. In children, there appear to be declines in levels of physical activity due to less walking and physical education. In both children and adults, there is an association between television viewing time and the risk of obesity.

Diet

Diet on societies become increasingly reliant on energy-dense, big-portions, and fast-food meals, the association between fast-food consumption and obesity becomes more concerning. Dietary energy supply per capita varies markedly between different regions and countries. It has also changed significantly over time. Total food energy consumption has been found to be related to obesity. An increase occurred in the average amount of food energy consumed. Most of this extra food energy came from an increase in carbohydrate consumption rather than fat consumption. The primary sources of these extra carbohydrates are sweetened beverages, fruit drinks, and iced tea is believed to be contributing to the rising rates of obesity and to an increased risk of metabolic syndrome and type 2 diabetes.  Vitamin D deficiency is related to diseases associated with obesity.

Survival paradox

The paradox of  negative health consequences of obesity in the general population are well supported by the available evidence, health outcomes in certain subgroups seem to be improved at an increased BMI, a phenomenon known as the obesity survival paradox. The paradox was first described in 1999 in overweight and obese people undergoing hemodialysis and has subsequently been found in those with heart failure and peripheral artery disease (PAD).

Nutrition

Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It includes ingestion, absorption, assimilation, biosynthesis, catabolism and excretion. The science that studies the physiological process of nutrition is called nutritional science