Trying to get ripped up for a competition or for personal goals can be an extremely difficult feat to accomplish. Everyone wants to have that ripped look where your skin is paper-thin and veins popping out everywhere. However, achieving that look takes an extreme amount of will power, guts, and dedication in the gym. Your body does not understand the mind of a bodybuilder, and thinks, "I starving, there is a drought, calories are insufficient, I am losing bodyfat…slow down all metabolic systems until bodyfat return to normal." Your own body tries to sabotage your competition goals of losing fat by slowing down your metabolism and breaking down lean muscle mass as an energy source. During a calorie-restricted diet the sympathetic nervous system is decreased, resulting in a reduced metabolic rate, thus conserving reserves of nutrients - although this is not necessarily true for adipose tissue (1). During fasting or calorie restriction, adipose tissue readily releases stored energy. That is where thermogenic supplements come in handy because they increase sympathetic nervous system activity and restores sympathetic tone. One of the ways caffeine and ephedrine stimulate lipolysis is by increasing the release of ‘fight-or flight’ hormones called catecholamines. The major catecholamines are dopamine, norepinephrine, and epinephrine (also known as adrenaline). Maintaining or increasing lean body mass should be one of the most important strategies for any weight reduction program. By maintaining lean muscle, mass during dieting maintains the body's thermogenic response to food and basal metabolic rate.
Catecholamines' and Adipose Tissue Regulation

Stimulating fat metabolism is the result of mobilizing fat stores in which stored fat is mobilized by the hydrolysis of free fatty acids and glycerol. This is initiated by the rise in a variety of hormones such as norepinephrine, epinephrine, ACTH, and glucagon. The mechanisms of these lipolytic hormones are believed to be mediated by an increase in cAMP. Lipolytic hormones activate adenylate cyclase, resulting in increased synthesis of cAMP-dependent protein kinases and subsequent phosphyorylation and activation of hormone-sensitive lipase, resulting in the hydrolysis of stored triglycerides to glycerol and free fatty acids (2). See figure 1 for details.

Hormone sensitive lipase is the rate-limiting enzyme in triglyceride breakdown and lipolysis. Adenylate Cyclase is an enzyme that activates cAMP or Cyclic Adenosine Monophosphate in the cell. cAMP promotes breakdown of stored fats, regulates thermogenic responses to food, increases the body's basal metabolic rate, and increases the utilization of body-fat.

Catecholamines increase fat lipolysis and reduce adipogenesis or the creation of new fat (3). During calorie-restricted diets, there is normally a rise in free fatty acids and glycerol, as fats are mobilized as an energy source. Catecholamines are so important to stimulating lipolysis that if a person is fasting and is administered a ? adrenergic blockade drug such as propranolol (i.e. a drug that blocks the sympathetic nervous system), the rise in serum fatty acids and glycerol is abolished (4). The use of GH is a great drug for stimulating lipolysis. Chronic exposure to GH increases the responses to catecholamines; the mechanism in unclear, but the hormones can increase the ? adrenergic receptor number and increase cAMP production (5). Interestingly, glucocorticoids such as cortisol also increase ? adrenergic receptor number, but decrease maximal adenylate cyclase activity and reduce cAMP production in fat cells reducing fat loss (6).