Caffeine Diet

Caffeine, a substance naturally occurring in tea leaves, kola nuts, coffee and cocoa beans, is commonly used as an appetite suppressant. The human body has no nutritional requirement for caffeine, however over 90 percent of the population regularly consume caffeine in the form of coffee, tea, soda and chocolate. Caffeine in moderation is not harmful; however, it should not be used for dieting purposes alone, but rather in conjunction with a healthy lifestyle, including exercise and a balanced diet.

Weight Loss

Caffeine may temporarily suppress appetite, and increase thermogenesis, the process by which your body burns additional calories through the production of heat and energy from food. The "American Journal of Clinical Nutrition" concluded that increases in caffeine may lead to a small reduction in long-term weight gain, although there is no medical research that proves that caffeine can produce long-term weight loss.

Water Weight Loss

Caffeine is a diuretic and can cause increased urination, which may promote temporary loss of water weight; however, it is important to guard against dehydration, which may negatively affect weight loss efforts. According to a German study published in the "Journal of Clinical Endocrinology & Metabolism", metabolic rate was increased by 30 percent after drinking two glasses of water.

Long-Term Weight Gain

Caffeine causes a release of the neurotransmitter adrenaline, which in turn promotes increased cortisol levels. According to Eugene Wells, author of "The Decaf Diet: Is Caffeine Making You Fat?," elevated cortisol levels promote appetite and may lead to overeating. Wells explains that prolonged elevated cortisol levels also contribute to breakdown of lean muscle mass, resulting in a lowered metabolic rate. Lastly, elevated cortisol levels promote more fat storage in the center of the body, causing an increase in belly fat. Although caffeine may assist with short-term weight loss, in the longer term, heavy caffeine consumption is more likely to lead to weight gain.

Side Effects

According to Mayo Clinic, a moderate amount of 200 to 300 mg, or two to four cups, of brewed coffee per day is not harmful. However, excessive caffeine consumption, or consuming more than 500 mg, or 4 cups, of coffee may lead to symptoms of insomnia, irritability, nervousness, fast heart beat and upset stomach. Avoid diet pills, which often contain high levels of caffeine and other ingredients that may have dangerous side effects, such as headaches, heart problems, high blood pressure, liver damage, breathing problems and nausea.