Name: Larry Ball
Bio 271- WA 2017SP
Obesity / Pre-obesity
Energy balance is a fundamental principle of physics that regulate weight gain and loss. An organism will stock fat when absorbing more energy through feeding than what it consumed by physical activity and its basal metabolism.The opposite is also true: reducing calorie intake and increasing physical activity creates a negative balance that translates into weight loss. Even when admitting that the main cause of obesity is an inadequacy between energy intake and expenditure, there remains a lot to be learned in order to properly manage the epidemic. Research is barely shedding light on the mysteries of this complex disorder. In Canada, between 1981 to 2004, daily calorie intake got up of 17%, that is 381 calories per day. The theory may sound simple, but reaching and maintaining a healthy weight remains difficult in the present environment. Research on the influence of physiological, behavioural and environmental factors on energy balance is essential to the development and implementation of effective prevention and treatment programmes. Despite significant recent advancements made towards unraveling the complexity of obesity, there still remain a large number of unanswered questions. The available data suggest that multiple systems regulate energy homeostasis. Familial clustering and the high concordance of body weight among monozygotic twins provide strong evidence for a genetic component to human obesity and a number of genes associated with human obesity have been identified. Research must advance knowledge within and across these domains in order to understand the interactions of known homeostatic mechanisms, recognize new ones, and place these into the context of the human-environment interface. The obesity epidemic did not occur overnight. Obesity and overweight are chronic conditions. Overall there are a variety of factors that play a role in obesity. This makes it a complex health issue to address.
Breathing disorders (e.g., sleep apnea, chronic obstructive pulmonary disease), certain types of cancers (e.g., prostate and bowel cancer in men, breast and uterine cancer in women), coronary artery (heart) disease, depression, diabetes, gallbladder or liver disease, gastroesophageal reflux disease (GERD), high blood pressure, high cholesterol, joint disease (e.g., osteoarthritis), and stroke. People who are obese may have the symptoms of the medical conditions mentioned above. High blood pressure, high cholesterol levels, breathing problems, and joint pain (in the knees or lower back) are common. The more obese a person is, the more likely they are to have medical problems related to obesity.
Aside from the medical complications, obesity is also linked to psychosocial problems such as low self-esteem, discrimination, difficulty finding employment, and reduced quality of life.
Skeletal System
Vertebral Column:
Excessive body mass (hence weight) causes compression wear to the vertebrae of the spine. This can lead to conditions such as scoliosis and/or trapped sciatic nerve(s).

Hip Joints:
Obesity can increase risk of fracture of the head of the femur, especially in post-menopausal women.

Knee Joints:
The risk of degenerative diseases affecting the knee joints is higher in people who are significantly overweight.

Vascular System (Blood Supply)
Increased risk of heart disease and heart attack:

Arteries (& arterioles):
Obesity is associated with increased risk of:

atherosclerosis (hardening of artery walls due to accumulation of fatty materials, e.g. cholesterol, making artery walls thicker)
arteriosclerosis (stiffening of arteries)
hypertension (high blood pressure).

These conditions increase the risks of thrombosis, strokes and brain hemorrhages - any one of which can be debilitating or even fatal.

Obesity increases the risk of varicose veins
Respiratory System
Obesity can increase the risk of lung infections because significantly larger body mass restricts movement of the diaphragm, in turn limiting flow in and out of the lungs.
Digestive System
Hiatus Hernia:
A hiatus hernia is an abnormality in which where part of the stomach protrudes through a defect in the diaphragm and up into the chest. This can increase the possibility of "reflux acid" into the esophagus, causing heartburn and other symptoms. Obesity is a "risk factor" re. development of a hiatus hernia (Ref.

Chronic liver disease (cirrhosis) is associated with obesity as well as with excessive consumption of alcohol.

Obesity is associated with various pancreatic conditions including pancreatic cancer and impaired endocrine function leading to diabetes.

Gallstones are more common in people who are significantly overweight, and especially in those who