The weight loss is the process of losing body weight, typically by losing fat. The weight loss can be achieved by consuming low-calorie diets and completely expending the consumed calories. There are different methods to achieve weight loss. It can be achieved by reducing the amount of food consumed, increasing physical activity or a combination of the two. The experts recommend a combination of healthy eating patterns and regular physical exercise for a healthy weight loss.
The Weight loss can also be achieved by surgical methods. Liposuction removes targeted area of fat and tissue while bariatric surgeries can result in large weight loss by reducing the size of the stomach or reducing the absorption of food energy. The surgical and drug options may have serious side effects.

Weight Loss Pills or drugs: The weight loss diet pills are one of the methods of losing weight. The Weight loss pills are medication or drug that helps losing weight. The Weight loss pills may also termed as anti-obesity drugs. The anti-obesity drugs include all pharmacological treatments intended to reduce or control weight. The weight loss pills or anti-obesity drugs may be prescribed or herbal drugs or chemicals that decrease appetite and/or increase physical activity, such as fenfluoramine, ephedra, nicotine or cocaine.

As these drugs are intended to alter one of the fundamental processes of the human body, the weight loss drugs are medically prescribed only in cases of morbid obesity, where weight loss is life-saving.

The Weight loss pills or Anti-obesity drugs operate through one or more of the following mechanisms:
Suppression of the appetite.
Increase of the body's metabolism.
Interference with the body's ability to absorb specific nutrients in food.

Anorectics: The Anorectics are substances that reduce the desire to eat. The Anorectics are also known as Anorexigenics. The Anorectics primarily intended to suppress the appetite, but most of the drugs in this class also act as stimulants (dexedrine, e.g.), and patients have abused drugs “off label” to suppress appetite (e.g. digoxin). These appetite suppressants are used to treat obesity.

Amphetamine: Amphetamine is a synthetic drug used as an appetite suppressant. Amphetamine and its derivatives (amphetamines) are part of a broader class of compounds called phenethylamines.

Fen-phen: Fen-phen, an anorectic, was an anti-obesity medication, which consisted of two drugs: fenfluramine and phentermine.
Fenfluramine, also known as Pondimin, was introduced on the U.S. market in 1973. Fenfluramine was withdrawn from the U.S. market in 1997 after reports of heart valve disease and pulmonary hypertension.
Phentermine is still available by itself in most countries, including the U.S. Internationally. Phentermine is a Schedule IV drug under the Convention on Psychotropic Substances

Ephedra: Ephedra is a genus of gymnosperm shrubs, the only genus in the family Ephedraceae and order Ephedrales. These plants occur in dry climates over a wide area mainly in the Northern Hemisphere, across southern Europe, north Africa, southwest and central Asia, southwestern North America, and, in the Southern Hemisphere, in South America south to Patagonia. They are also called Joint-pine, Jointfir, or Mormon-tea. The Chinese name is ‘ma huang’, which means "yellow hemp". Ephedra is also sometimes called sea grape (from the French raisin de mer), although that is also a common name for Coccoloba uvifera.

Ephedra was found in many popular weight control products. On December 30, 2003, the US Food and Drug Administration announced a ban (effective from 12 April 2004) on the uncontrolled sale of supplement products containing Ephedra, citing "an unreasonable risk of illness or injury" from the use of the drug. On 14 April 2005, this ban was struck down on procedural grounds by Utah federal judge Tena Campbell.

Ephedrine is considered a performance-enhancing drug and is prohibited in most competitive sports. In the 1994 FIFA World Cup, the Argentine footballer Diego Armando Maradona tested positive for ephedrine in a doping control for using one dietary supplement product containing the substance.

Cocaine: Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. It is a stimulant of the central nervous system and an appetite suppressant.

Side Effects: The use of the weight loss medication can cause some serious side effects including physical illness or disorders, heart valve disease, pulmonary hypertension etc.

Many amphetamines produce side effects including addiction, tachycardia and hypertension, making prolonged unsupervised use dangerous.

A loss of weight can also be the symptom of some mental or physical diseases or disorders, such as anorexia nervosa or the cachexia associated with cancer or AIDS.