| A: Maintaining body weight during periods of intense exercise and competition can be a challenge for athletes. Additionally, weight gain may occur during periods of rest or time off. Many factors influence body weight including gender, age, duration and intensity of exercise, body size, body composition, and hydration status. Body weight depends on energy balance, which is the difference energy intake and energy expenditure. Energy intake comes form calorie containing foods and fluid, where as energy expenditure consists of basal metabolic rate, the thermic effect of food, and calories burned during exercise and movement.
The calories intake recommended per day for men and women of various ages are listed below:
| Age |
Women |
Men |
| 15-18 |
2200 |
3000 |
| 19-24 |
2200 |
2900 |
| 25-50 |
2200 |
2900 |
| 51+ |
1900 |
2300 |
*Values are adapted from Recommended Dietary Allowances, national Academy of Sciences, 1989.
These values do not include calories associated with exercise. The number of calories for a given activity varies depending on the type of exercise, your body size, and the duration and intensity of the exercise. Listed below are various activities and the estimated calories consumed during 30 minutes of exercise for different body weights. Keep in mind that these values are only estimates. The actual calories consumed during exercise depend on the individual.
| Activity (with minutes per mile) |
Calories burned by Weight Class |
| 120 lb. |
140 lb. |
160 lb. |
190 lb. |
| Walking 30 min/mile |
72 |
84 |
96 |
114 |
| Walking 20 min/mile |
96 |
112 |
128 |
152 |
| Walking 15 min/mile |
120 |
140 |
160 |
190 |
| Jog/walk 12 min/mile |
222 |
259 |
296 |
352 |
| Running 10 min/mile |
276 |
322 |
368 |
437 |
| Running 7.5 min/mile |
366 |
427 |
488 |
579 |
| Running 6.7 min/mile |
396 |
462 |
528 |
627 |
| Running 6 min/mile |
420 |
490 |
560 |
627 |
| Stair climbing machine |
192 |
224 |
256 |
304 |
| Hiking, no load |
186 |
217 |
248 |
294 |
*Values are estimates based on body weight, adapted from www.nutribase.com.
Estimating your calorie needs for weight maintenance can be done using these values. For example, a 160 pound 45 year old male that runs 90 minutes per day averaging 7.5 minutes per mile will need to consume approximately 4400 calories (e.g. 2900 + 1464 kcal) each day to maintain weight. Of the 4400 calories approximately 1464 calories are associated with running. If he consumes ~4400 calories, he will be in energy balance and his weight will remain stable. Conversely, if he eats less than 3900 calories weight loss will occur over time. A calorie deficit of 500 calories per day over a week will result in a 1-pound per week weight loss. Additionally, an increase in calories above what is burned will result in weight gain. For athletes, weight maintenance is important to prevent muscle loss, protect immune function, and promote optimal physical performance. Persistent sub-optimal intake of calories can contribute to a loss of strength and endurance, and possible nutrient deficiencies.
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