What are the health risks for being too skinny, and too fat? and how do they affect your daily like style?

Anorexia/Anorexia nervosa
The term anorexia denotes a loss of appetite. If a person is lacking a drive to eat through a non-mental health standpoint, the person has anorexia. Many people, when they are ill, have anorexia. Extreme/long term anorexia follows the same disease process as anorexia nervosa. Anorexia nervosa is the mental health term used as a diagnosis of a person with a willful desire to not eat in order to be skinny. The person with anorexia nervosa will always see themselves as fat no matter if they are grossly malnourished and void of adipose (fat) and muscle mass. These people are at an extreme risk of death, even in treatment. While suffering from the mental illness, they are depleting all stores of energy. The body will first use the sugar stored in the body and made in the liver by glycogenesis. Then the body will turn to the metabolism of protein, often found in muscle. After the protein stores are exhausted, the body turns to the fat to metabolize. This is why many ‘diets’ fail due to the fact that the fact that the body utilizes the fat stores last. Throughout this process of the body metabolizing itself, the kidneys are working to excrete the nitrogenous wastes from the protein and the ketones from the fat breakdown. Ultimately, the kidney fail and the person may need to resort to dialysis. The liver is also attempting to keep the body in homeostasis by filtering the blood of the byproducts of the breakdown of tissue. The liver will fail and will result in cirrhosis, needing to be replaced. The gastrointestinal tract will atrophy and the normal flora will escape it confines and be released into the systemic circulation causing sepsis. Sepsis is a whole other disease process with a high mortality rate. The heart is depleted of its energy reserves and becomes weak, which can lead to heart failure and cardiogenic shock. The brain, which uses a vast amount of sugar to operate, slows and is unable to regulate normal body function. This is why if a person’s blood sugar falls too low, they generally act drunk – slurring words, stumbling, incomplete thoughts, and such. If a person is brought into treatment for anorexia nervosa care must be taken not to cause refeeding syndrome. This is a potentially fatal process that occurs when the patient is fed too much too quickly causing an influx of electrolytes and hormones.
Overweight/Obesity
Excess body fat can cause numerous health issues from type 2 diabetes to heart failure. Type 2 diabetes happens when the insulin producing cells of the pancreas are decreased in number or the body’s general cells become resistant to the effects of the insulin. This may cause an increase in blood glucose (sugar) and may lead to hyperosmolar hyperglycemic non-ketotic syndrome (HHNS) where the blood glucose level is extremely elevated, sometimes up to 900 mg/dL as opposed to the normal range of 70 – 100 mg/dL. This is a life threatening situation which requires hospitalization. People with HHNS will have polyphagia (extremely hungry), polydipsia (extremely thirsty), and polyuria (excessive urination) due to the physiological need to replenish reserves, dilute the sugar, and excrete the excess sugar, respectively. In obesity, cirrhosis of the liver may result as it attempts to store fat and filter toxic substances from the blood. The heart becomes overloaded due to the miles of extra blood capillaries needed to feed the excess fat tissue. This will lead to heart failure which in turn floods the lungs with excess blood causing atelectasis, shortness of breath, and possible syncope due to inadequate oxygenation of blood. The heart and arteries fill with plaque causing atherosclerosis that may lead to a myocardial infarction (MI/heart attack) or stroke. The kidneys may fail due to the decrease in blood supply and exhaustion from filtering the blood.
Summary
All in all, being too skinny or too fat is unhealthy. Neither is better or worse. Both lead to a substandard quality of life whether it is minor inconveniences or major heath disparities. This is a simple overview of a few specific disease processes that are involved with being outside a healthy weight. If further information is desired, a true medical textbook or dictionary is recommended.