Weight loss

Related Terms

Adipex-P®, adjustable gastric banding, biliopancreatic diversion, bitter orange, BMI, body mass index, dexfenfluramine, dietary supplements, diethylpropion, Dietrine Carb Blocker with Phase 2®, ephedra, ephedrine, ephedrinum, fenfluramine, gastric bypass surgery, hoodia, jaw wiring, liposuction, ma huang, Meridia®, obesity treatment, orlistat, phentermine, phenylpropanolamine, Pondimin, PPA, redux, sibutramine, Tenuate®, vertical banded gastroplasty, waist circumference, weight loss, weight loss drugs, weight loss supplements, weight loss surgery, Xenical®.

appetite suppressants background

Appetite suppressants are agents that promote weight loss by decreasing appetite or increasing the sensation of fullness. About one-quarter of the U.S. population can be considered obese (BMI of >30). Four million of these people may be classified as morbidly obese (BMI of >40). Obesity is associated with increased risk of hypertension, type 2 diabetes and heart disease. The use of appetite suppressant medications to treat obesity in combination with physical activity and diet modification is often recommended to lose and maintain weight successfully over the long term.

appetite suppressants theory/evidence

Several prescription medications are currently approved for treatment of obesity. In general, the effects of these medications are modest, leading to an average initial weight loss of between 5 and 22 pounds; though studies show that weight returns after cessation of the drugs. There is considerable individual difference in response to these medications; some people experience greater weight loss than others.
Short-term use of appetite suppressant medications has been shown to modestly reduce health risks for obese individuals. Studies have found that these medications can lower blood pressure, blood cholesterol, blood fats (triglycerides), and decrease insulin resistance (the body's ability to utilize blood sugar). Long-term studies need to be conducted to determine if weight loss assisted by appetite suppressant medications can improve health long-term.
Weight loss tends to be greatest during the first few weeks or months of treatment, leveling off after about six months. Research suggests that if a patient does not lose at least four pounds during the first four weeks on a particular medication, that medication is unlikely to be effective over the long run.
Short-term use (few weeks to few months): Examples include diethylpropion (Tenuate®), and phentermine (Adipex-P®).
The mechanism of action of diethylpropion and phentermine appears to be secondary to CNS (central nervous system) effects, specifically stimulation of the hypothalamus to release catecholamines into the central nervous system. Appetite suppressing effects are mediated via norepinephrine and dopamine metabolism.
Long-term use (up to one year or more): Examples include orlistat (Xenical®) and sibutramine (Meridia®).
Orlistat is the first prescription treatment for obesity that does not act as an appetite suppressant. It works by interfering with the action of gastrointestinal (GI) lipase in the GI tract. As a result of this mechanism of action, 30% of ingested dietary fat is not absorbed.
Sibutramine and its two primary metabolites also appear to be secondary to CNS effects by blocking the neuronal uptake of norepinephrine, serotonin, and dopamine.
OTC (over-the-counter): It is believed that "P57" molecule in Hoodia mimics the effect that glucose has on your brain, telling part of your brain (the hypothalamus) that you feel full. Consequently, you have no desire to eat. However current available evidence on hoodia's effectiveness and safety is lacking.
Dietrine Carb Blocker with Phase 2®: An ingredient extracted from white kidney beans is thought toneutralize the digestive enzyme alpha amylase before it can convert starch into glucose and then fat.

gastric bypass surgery background

Gastric bypass surgery is the most common weight loss surgery which uses bands or staples to create food intake restriction. The bands or staples are surgically placed near the top of the stomach to section off a small portion that is often called a stomach pouch. A small outlet, about the size of a pencil eraser, is left at the bottom of the stomach pouch. Since the outlet is small, food stays in the pouch longer and you also feel full for a longer time.
This surgery is often performed in those who have a BMI ≥40 (extremely obese) or BMI between 35 and 39.9 and with weight related health problems such as diabetes or high blood pressure.
Surgical candidates go through an extensive screening process. Not everyone who meets the criteria for the surgery is psychologically or medically ready for the surgical procedure. A team of professionals, including a physician, dietitian, psychologist and surgeon, evaluate whether the surgery is appropriate. Following surgery, physical, nutritional and metabolic counseling are given to prevent nutritional deficiencies. Lifelong use of nutritional supplements such as multivitamins, vitamin B12, vitamin D and calcium is recommended.
Researchers have found greater weight loss in gastric bypass (93.3 pounds) compared to gastroplasty (67 pounds) after one year. Over two years, gastric bypass surgery patients have been shown to lose two-thirds of excess weight. The success rate for weight loss for RGB is 68 to 72% of excess body weight over a three-year period, and 75% for BPD. After five years, the average excess weight loss from gastric bypass surgery ranges from 48 to 74%.
The improvements observed in type 2 diabetes, high blood pressure and high blood cholesterol may significantly decrease the risk of cardiovascular events in individuals who have undergone gastric bypass surgery compared with those treated through other means. Gastric bypass surgery has also shown to improve mobility and quality of life for people who are severely overweight.

risks of gastric bypass surgery

A risk of death has been associated with gastric bypass surgery. The risk varies depending on age, general health and other medical conditions. Talk to your doctor about the exact level of risk gastric bypass surgery may pose for you.
Blood clots in the legs are more likely to occur in very overweight people. Blood clots can be dangerous. In some cases, they travel to the lungs and lodge in the lungs' arteries causing a pulmonary embolism, a serious condition that damages lung tissue and can lead to death. Walking and using leg wraps that apply intermittent pressure to the leg can help reduce this risk of blood clots in the legs.
Leaking at one of the staple lines in the stomach has occurred and can be treated with antibiotics. Most cases heal with time. Sometimes, the leak can be serious enough to require emergency surgery.
Excess weight places extra stress on the chest cavity and lungs. This means a higher risk of developing pneumonia after the surgery.
Narrowing of the opening between the stomach and small intestine has occurred. This rare complication may require either an outpatient procedure to pass a tube through your mouth to widen (dilate) the narrowed opening or corrective surgery.
Gastric bypass can also cause dumping syndrome, a condition where stomach contents move too quickly through the small intestine causing nausea, vomiting, diarrhea, dizziness and sweating.
Other common complications include vitamin and mineral deficiency, dehydration, gallstones, bleeding stomach ulcer, hernia at the incision site, and intolerance to certain foods.

other types of weight loss surgery

Adjustable gastric banding: The surgeon uses an inflatable band to partition the stomach into two parts. He or she then wraps the band around the upper part of your stomach and pulls it tight, like a belt, creating a tiny channel between the two pouches. The band keeps the opening from expanding and is designed to stay in place indefinitely. But it can be adjusted or surgically removed if necessary. Most surgeons perform this operation using a laparoscope.
Biliopancreatic diversion: In this procedure, a portion of your stomach is removed. The remaining pouch is connected directly to your small intestine, but completely bypasses your duodenum and jejunum where most nutrient absorption takes place. This weight-loss surgery offers sustained weight loss, but it presents a greater risk of malnutrition and vitamin deficiencies and requires close monitoring.
Jaw wiring: This is a form of food intake restriction for temporary use in patients without respiratory problems. It can be effective for short-term weight loss. However, weight regain occurs soon after the wires are removed.
Liposuction: This is the most frequent cosmetic operation in the United States in which fat tissue is removed. Relatively small amounts of total body fat can be removed safely, however, and little weight is lost.
Vertical banded gastroplasty: This operation divides the stomach into two parts - limiting space for food and forcing you to eat less. There is no bypass. Using a surgical stapler, the surgeon divides your stomach into upper and lower sections. The upper pouch is small and empties into the lower pouch (the rest of the stomach). Surgeons use this procedure less commonly than gastric bypass, partly because it does not lead to adequate long-term weight loss.