Dietary imbalance and over nutrition may lead to diseases like obesity. Aesthetic considerations aside, obesity is defined as an excess of adipose tissue that imparts a health risk, a body weight of 20% excess over ideal weight for age, sex and height is considered a health risk.
Obesity results when caloric intake exceeds utilization. The imbalance of these two components can occur in the following situations:
- Inadequate pushing of oneself away from the dining table causing overheating.
- Insufficient pushing of oneself out of the chair leading to inactivity and a sedentary lifestyle.
- Genetic predisposition to develop obesity.
- Diets largely derived from carbohydrates and fats than protein-rich diet.
- Secondary obesity may result following a number of underlying diseases such as hypothyroidism, Cushing’s disease, insulinoma and hypothalamic disorders.
- Hyperinsulinaemia: Increased insulin secretion is a feature of obesity. Many obese patients exhibit hyperglycemia. This is due to a state of insulin resistance consequent to tissue insensitivity.
- Non-insulin dependent diabetes: There is a strong association of non insulin dependent diabetes mellitus with obesity.
- Hypertension: A strong association between hypertension and obesity is observed, which is perhaps due to increased blood volume. Weight reduction leads to significant reduction in systolic blood pressure.
- Hyperlipoproteinaemia: Obesity is strongly associated with VLDL and mildly with LDL. Total blood cholesterol levels are also elevated in obesity.
- Atherosclerosis: Obesity predisposes to development of atherosclerosis.
- Coronary artery disease and stroke: As a result of atherosclerosis and hypertension, there is increased risk of myocardial infarction and stroke in obese individuals.
- Cholelithiasis: There is six times higher incidence of gallstones in obese individuals, mainly due to increased body cholesterols.
- Hypoventilation Syndrome (Pickvickian syndrome): This is characterized by hypersomnolence both at night and during the day in obese individuals along with the features of hypercapnia, hypoxia, polycythaemia and eventually right-sided heart failure.
- Osteoarthritis: these individuals are more prone to develop degenerative joint disease due to wear and tear following trauma to joints as a result of large body weight.
- Cancer: Certain cancers such as endometrial and breast seem to be related to obesity.
It is a state of overall deprivation of nutrients and can affect all ages. A starve individual has lax, dry skin, wasted muscles and atrophy of internal organs.
- During fasting state, insulin independent tissues such as the brain, blood cells, etc. Continue to utilize the glucose, while insulin dependent tissues like muscles stop taking glucose. This results in the release of glycogen stores in the liver to maintain normal blood glucose level.
- Proteins break down to release amino acids, which are used as fuel for hepatic gluconeogenesis so as to maintain glucose needs of the brain. This results in nitrogen imbalance due to excretion of nitrogen compounds as urea.
- After about one week of starvation, protein breakdown is decreased while triglycerides of the adipose tissue breakdown to form glycerol and fatty acids. Starvation can then continue till all the body fat stores are exhausted following which death occurs.