9 Months to Tri

[Jamie]  Hello all! In light of Chris’ recent post regarding weight changes, body composition, and overall progress, I thought this post would be worthwhile. The foods and beverages we consume serve dual functions: 1) immediate fuel sources for the body, and 2) later sources of energy (read: calories) for the body, i.e. our “energy stores.” Energy stores play multiple important roles as they relate to exercise performance. Why, you may ask? Our energy stores contribute to:a. Our size and physique (e.g. body fat and muscle mass)b. Our function (e.g. muscle mass)c.) Fuel used for exercise (e.g. we store extra carbohydrate in our muscles and liver for times when our immediate supply runs out). How much food an athlete needs to eat varies depending on his or her energy needs. There are formulas to estimate these, but unfortunately our bodies are not machines so its difficult to obtain 100% accuracy here. Energy (remember, energy = calories) needs depend not only on the intensity of planned exercise, but also on energy expenditure outside of these activities. As such, for those who train frequently, and also when training sessions are long and hard, energy demands are high. On the other hand, for those who don’t train as much (i.e. during times of injury or during an “off season”), or for those who engage in lower intensity activities, energy needs are lower and food intake must be modified appropriately during those times. 2 key points to remember here: 1) Body weight, although it CAN be telling, is NOT a 100% reliable indicator of energy balance (if we are in energy balance, our calories in = calories out; if negative EB we lose weight, and if positive EB we gain weight). Monitoring body weight can be misleading at times, and the information may be misinterpreted. 2) Monitoring body fat across a training period, when taken by the same (trained) person, can give up useful information about changes in body fat stores. There are times when it becomes necessary to manipulate energy intake to achieve specific goals, such as increasing muscle mass or losing body fat. Keep in mind that losing body weight will not be helpful for the swimmer who wants to increase power and sprinting (I think you can sprint in a pool! ) speed if the weight is lost as muscle rather than body fat. Therefore, simply eating less will not necessarily be the solution. Likewise, gaining body weight may make sense for some athletes at some point in their careers, but if the weight is gained as fat, it will do more harm than good. When an athlete wants to reduce body fat, this should be achieved gradually and without compromising his/her ability to consume an adequate intake of fuel and important nutrients. Careful management of both diet and activity levels in the off season and during most stages of training can help an athlete achieve ideal body weight/body fat levels without negatively influencing performance. Lastly, as an FYI for the technical geeks (aka, me): Evidence from recent research shows that there are significant impairments of metabolic and hormonal function when energy availability drops below a daily intake of 30 calories per kg of fat free mass. Keep in mind that Energy Availability = total dietary energy intake - energy used in daily activities and training. This deficiency can affect performance, growth and overall health.

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