If you love to drink a tall, cool one after playing sport, you're not alone. Either exploiting this or creating it, advertisers have for years used the image of healthy, young people downing a few after sport. Alcohol's also heavily involved in sponsoring professional athletes and sporting events such as Grand Prix, tennis tournaments such as the Australian Open, and the Rugby World Cup (backed by Heineken and Bundaberg) in Australia starting this month. Yet, while the taste may be appealing, alcohol in any form is detrimental to many aspects of physical activity. The stuff in alcohol that makes you drunk is ethanol, a chemical compound that comes from the fermentation of grains. As soon as it enters your body, it's treated differently to other nutrients. To begin with, it's a highly concentrated source of calories containing seven calories per gram compared with four for protein and carbohydrates and nine for fat. Alcohol calories aren't used for muscle contraction but instead are used by the body for heat production. Overloading the metabolic pathways of the liver makes the organ convert these calories quickly into fat, so they can be easily stored before being carried away to permanent fat storage sites. Secondly, all these calories are empty. Alcohol doesn't contain any significant amounts of vitamins or minerals and robs your body of these crucial trace elements and enzymes. Alcohol causes intestinal cells to stop absorbing thiamin, folacin and B12. Your kidneys excrete an increased amount of magnesium, calcium, potassium and zinc, leaving your body empty of these vital minerals. While some may argue that beer contains B vitamins, you need to drink at least 11 cans of beer to get the same amount of B2 (riboflavin) you would in a piece of whole grain bread. Alcohol affects a number of hormones in the body. Since it's a diuretic, it causes you to lose more fluid (along with electrolytes and minerals) than it contains. It also decreases production of an antidiuretic hormone found in the brain that regulates fluid balance. Alcohol use has been shown to reduce muscular protein synthesis in certain fast-twitch fibres by influencing two growth hormones, insulin and growth hormone. For anyone looking to increase muscle strength, power and speed, abstaining from alcohol for a while, especially right after exercise, will aid in the process. Reading this, you may think, 'but a few drinks won't hurt!' And the occasional glass of red wine has been shown to be healthy. True, but when it comes to sport, studies have shown that even a very small amount of alcohol can impair psychomotor skills, reaction time, hand-eye co-ordination, visual tracking, balance and alertness, because of the way alcohol affects the central nervous system. Drinking also accentuates fatigue by increasing lactic acid production. Blood vessels are dilated, diverting circulation to the skin. So when it's cold, there's an increased risk of hypothermia and when it's hot, sweating is increased, resulting in further dehydration. Whether you're celebrating or crying, alcohol in excess after a sports event can set your body's recovery back by weeks, because when alcohol is in the body, the healing process stops. Any athlete who hasn't been affected by alcohol can safely say they haven't achieved a very high level of activity in the first place. But if you must have that beer after the game, at least make sure you're well hydrated.