Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Body mass index (BMI), a measurement which compares weight and height, defines a person as overweight (pre-obese) when their BMI is between 25 kg/m2and 30 kg/m2, and obese when it is greater than 30 kg/m2.
Obesity increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, breathing difficulties during sleep, certain types of cancer, and osteoarthritis. Obesity is most commonly caused by a combination of excessive dietary calories, lack of physical activity, and genetic susceptibility, although a few cases are caused solely 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.
The primary treatment for obesity is dieting and physical exercise. To supplement this, or in case of failure, anti-obesity drugs may be taken to reduce appetite or inhibit fat absorption. In severe cases, surgery is performed or an intragastric balloon is placed to reduce stomach volume and/or bowel length, leading to earlier satiation and reduced ability to absorb nutrients from food.
Obesity is a leading preventable cause of death worldwide, with increasing prevalence in adults and children, and authorities view it as one of the most serious public health problems of the 21st century. Obesity is stigmatized in the modern Western world, though it has been perceived as a symbol of wealth and fertility at other times in history.
Obesity is defined by body mass index (BMI) and further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. BMI is closely related to both percentage body fat and total body fat.
| BMI | Classification |
| < 18.5 | underweight |
| 18.5–24.9 | normal weight |
| 25.0–29.9 | overweight |
| 30.0–34.9 | class I obesity |
| 35.0–39.9 | class II obesity |
| > 40.0 | class III obesity |
Any BMI ≥ 35 or 40 is severe obesity A BMI of ≥ 35 or 40–44.9 or 49.9 is morbid obesity A BMI of ≥ 45 or 50 is super obese
The rate of obesity also increases with age at least up to 50 or 60 years old and severe obesity in the United States, Australia, and Canada is increasing faster than the overall rate of obesity. Once considered a problem only of high-income countries, obesity rates are rising worldwide and affecting both the developed and developing world.
The main treatment for obesity consists of dieting and physical exercise. Diet programs may produce weight loss over the short term, but keeping this weight off can be a problem and often requires making exercise and a lower calorie diet a permanent part of a person’s lifestyle. Success rates of long-term weight loss maintenance are low and range from 2–20%. In a more structured setting, however, 67% of people who lost greater than 10% of their body mass maintained or continued to lose weight one year later. An average maintained weight loss of more than 3 kg (6.6 lb) or 3% of total body mass could be sustained for five years. Some studies have found significant benefits in mortality in certain populations with weight loss. In a prospective study of obese women with weight related diseases, intentional weight loss of any amount was associated with a 20% reduction in mortality. In obese women without obesity related illnesses a weight loss of greater than 9 kg (20 lb) was associated with a 25% reduction in mortality. A recent review concluded that certain subgroups such as those with type 2 diabetes and women show long term benefits in all cause mortality, while outcomes for men do not seem to be improved with weight loss. A subsequent study has found benefits in mortality from intentional weight loss in those who have severe obesity
The most effective treatment for obesity is bariatric surgery; however, due to its cost and the risk of complications, researchers are searching for other effective yet less invasive treatments.
Management
Very low calorie diets provide 200–800 kcal/day, maintaining protein intake but limiting calories from both fat and carbohydrates. They subject the body to starvation and produce an average weekly weight loss of 1.5–2.5 kilograms (3.3–5.5 lb). These diets are not recommended for general use as they are associated with adverse side effects such as loss of lean muscle mass, increased risks of gout, and electrolyte imbalances. People attempting these diets must be monitored closely by a physician to prevent complications.
A meta-analysis of 43 randomized controlled trials by the Cochrane Collaboration found that exercising alone led to limited weight loss. In combination with diet, however, it resulted in a 1 kilogram weight loss over dieting alone. A 1.5 kilogram (3.3 lb) loss was observed with a greater degree of exercise. Even though exercise as carried out in the general population has only modest effects, a dose response curve is found, and very intense exercise can lead to substantial weight loss. During 20 weeks of basic military training with no dietary restriction, obese military recruits lost 12.5 kg (27.6 lb). High levels of physical activity seem to be necessary to maintain weight loss. A pedometer appears useful for motivation. Over an average of 18-weeks of use physical activity increased by 27% resulting in a 0.38 decreased in BMI.
A number of popular programs exist, including Weight Watchers, Over-eaters Anonymous, and Jenny Craig. These appear to provide modest weight loss (2.9 kg, 6.4 lb) over dieting on one’s own (0.2 kg, 0.4 lb) over a two year period. Internet-based programs appear to be ineffective. The Chinese government has introduced a number of “fat farms” where obese children go for reinforced exercise, and has passed a law which requires students to exercise or play sports for an hour a day at school.
Weight loss with these drugs is modest. Over the longer term, average weight loss on orlistat is 2.9 kg (6.4 lb), sibutramine is 4.2 kg (9.3 lb) and rimonabant is 4.7 kg (10.4 lb). Orlistat and rimonabant lead to a reduced incidence of diabetes, and all three drugs have some effect on cholesterol. However, there is little information on how these drugs affect the longer-term complications or outcomes of obesity. In 2010 the FDA noted concerns that sibutramine increases the risk of heart attacks and strokes in patients with a history of cardiovascular disease.
There are a number of less commonly used medications. Some are only approved for short term use, others are used off-label, and still others are used illegally. Most are appetite suppressants that act on one or more neurotransmitters. Phendimetrazine (Bontril), diethylpropion(Tenuate), and phentermine (Adipex-P) are approved by the FDA for short term use, while bupropion (Wellbutrin), topiramate (Topamax), and zonisamide (Zonegran) are sometimes used off-label.
The usefulness of certain drugs depends upon the comorbities present. Metformin (Glucophage) is preferred in overweight diabetics, as it may lead to mild weight loss in comparison tosulfonylureas or insulin. The thiazolidinediones, on the other hand, may cause weight gain, but decrease central obesity. Diabetics also achieve modest weight loss with fluoxetine(Prozac), orlistat and sibutramine over 12–57 weeks. Preliminary evidence has however found higher number of cardiovascular events in people taking sibutramine verses control (11.4% vs. 10.0%). The long-term health benefits of these treatments remain unclear.
Fenfluramine and dexfenfluramine were withdrawn from the market in 1997,while ephedrine (found in the traditional Chinese herbal medicine má huáng made from the Ephedra sinica) was removed from the market in 2004. Dexamphetamines are not approved by the FDA for the treatment of obesity due to concerns regarding addiction. The use of these drugs is not recommended due to potential side effects. However, people do occasionally use these drugs illegally.
Surgery for severe obesity is associated with long-term weight loss and decreased overall mortality. One study found a weight loss of between 14% and 25% (depending on the type of procedure performed) at 10 years, and a 29% reduction in all cause mortality when compared to standard weight loss measures. A marked decrease in the risk of diabetes mellitus,cardiovascular disease and cancer has also been found after bariatric surgery. Marked weight loss occurs during the first few months after surgery, and the loss is sustained in the long term. In one study there was an unexplained increase in deaths from accidents and suicide, but this did not outweigh the benefit in terms of disease prevention. When the two main techniques are compared, gastric bypass procedures are found to lead to 30% more weight loss than banding procedures one year after surgery.
The effects of liposuction on obesity are less well determined. Some small studies show benefits while others show none. A treatment involving the placement of an intragastric balloon via gastroscopy has shown promise. One type of balloon lead to a weight loss of 5.7 BMI units over 6 months or 14.7 kg (32.4 lb). Regaining lost weight is common after removal, however, and 4.2% of people were intolerant of the device.
Way of Life Eating
Designed by Dr. Milton Moore
Most people starve themselves into being obese. Their body does not know when it will be fed after the one meal that is eaten, which is usually too many calories. Therefore some of the calories are stored as fat. It is imperative that every two to three hours some intake of calories is required to help speed up your metabolism. Some foods that can be used to provide calories between meals are:
- Granola Bar
- ½ of a Banana
- 5 to 10 almonds
- ½ handful Mixed Nuts
- ½ handful Raisins
The quantity of these foods should be small but enough to add at least 50 to 100 calories so that your body will not fear when it will be fed. Thereby not tending to store calories as fat, because it knows, it will be fed on a regular basis which allows your metabolism to speed up and burn calories. A small increase in exercise is essential to burn more calories on a regular daily basis.
- Walking several blocks after eating increasing in time.
- Cleaning the house, Yard work, etc.
- Not sitting at TV or going to bed immediately after eating.
The reason for the exercising is to prevent all of the blood from going to the stomach to absolve all of the calories. Your muscles will require some of this blood circulation, therefore depriving some of the blood flow. You should attempt to eat three to four meals a day six to eight hours apart.
In order to lose weight you must reduce the volume of food which would reduce the total calories to 1/2 of what you are currently eating.
Drinking water prior to eating will help to achieve the sensation of being full. It is important not to see any additional food when consuming this amount of food to prevent your brain from craving the food it sees. When eating at a restaurant, have the server cut in half the meal and put the other half in a container to go before eating. Take a pen and write down the time and date when you will consume the other half which should be at least eight hours later. Many restaurants are now offering half entrees on their menus. You can also order an appetizer as your meal instead of an entree.
If you desire to eat fast food, have them to split the order into two bags. Eat one and put time and date on the other bag as to when it is to be consumed (six to eight hours later). If you would like to have french fries ask for a quarter or half size instead of the full size. It is better to pay for than discard excess food than to consume and harm your body.
Try to identify trigger foods that you abuse on a daily or weekly basis (soft drinks, cookies, candy, ice cream, potato chips, etc.). You may enjoy these foods at a reduced rate of once or twice a week or on a specific day in small specific quantities (6 oz soft drinks, 3 – 6 cookies, 2 pieces of small or reasonable size candy, etc.)