Glutamine is an amino acid that is found in your muscles. Research has shown that after an intense workout, the glutamine levels in your body can drop by as much as 50%. Glutamine is also essential to keep your immune system functioning properly. As we all know, a poor immune system can leave you feeling weak and sick. According to a study by Trinity and All Saints University College, a routine supplementation of glutamine post-workout can help lessen the change of injury, improve immune function and help you recover faster after over training. 2 grams of L-glutamine daily is all that you need.
Triathlons combine cycling, swimming and running for a grueling test of fitness and speed. Harvard University assigns half-hour calorie deficits for these activities based on body weight. Cycling at 16 to 19 mph will cost you 360 calories at 125 pounds and 533 calories at 185 pounds. Swimming vigorous laps uses 300 calories and 444 calories, respectively. Running a 6-minute mile eats up 495 to 733 calories each half-hour based on your weight. Sustaining that level of intensity for hours is not realistic; calorie count decreases right along with speed and effort expended.
The conversion efficiency of energy from respiration into mechanical (physical) power depends on the type of food and on the type of physical energy usage (., which muscles are used, whether the muscle is used aerobically or anaerobically ). In general, the efficiency of muscles is rather low: only 18 to 26% of the energy available from respiration is converted into mechanical energy.  This low efficiency is the result of about 40% efficiency of generating ATP from the respiration of food, losses in converting energy from ATP into mechanical work inside the muscle, and mechanical losses inside the body. The latter two losses are dependent on the type of exercise and the type of muscle fibers being used (fast-twitch or slow-twitch). For an overall efficiency of 20%, one watt of mechanical power is equivalent to kcal (18 kJ) per hour. For example, a manufacturer of rowing equipment shows calories released from 'burning' food as four times the actual mechanical work, plus 300 kcal (1,300 kJ) per hour,  which amounts to about 20% efficiency at 250 watts of mechanical output. It can take up to 20 hours of little physical output (., walking) to "burn off" 4,000 kcal (17,000 kJ)  more than a body would otherwise consume. For reference, each kilogram of body fat is roughly equivalent to 32,300 kilojoules or 7,700 kilocalories of food energy (., 3,500 kilocalories per pound).