As we have discussed in other sections, the benefits of regular exercise are many and varied. However, performing general exercise activities compared to intense athletic ones such as those athletes do, can mean an extra energy demand for the body. This may require extra food intake, extra vitamins, minerals and other food stuffs.

Progressing from a sedentary type lifestyle to a very fit one will require extra energy due to greater exertion, which will allow you to reap even more health benefits. As a note, a good diet won’t substitute for neither training nor genetic makeup. However, a poor diet can harm athletic performance.

Athlete versus General Fitness

Initially, the key difference between the energy demands for athletes versus general fitness practitioners is due to the intensity of exercise performed. This is important because of the association with weight gain versus energy output. For example, a small person might need only 1800 kcal daily to sustain normal daily activities without losing body weight, while a large, muscular man may need 4000 kcal daily. Thus, there is a wide range in caloric needs.

If you are 100 pounds and perform typical exercises for either aerobics, average jogging, or circuit-weight training using machines, your total daily caloric needs on activity days may be up to 1800 kcal. However, an athlete that performs 4 hours of cycling over steep terrain can require an additional 1300 calories per day. As a result, some athletes, especially those ranging up to 200 pounds or more, may require up to 7000 kcal daily just to maintain body weight during training, whereas others may need only 1800 kcal or less.

How Do We Know If One is Consuming Enough Food Energy?

There is a simple procedure to answer this question. First, measure your body fat. For male athletes, it should range from about 5-15% and for female athletes, about 10-25%. If you are a general fitness practitioner the respective ranges would typically be 15-20% and 20-28%. Second, monitor your body weight on a regular basis, i.e., weekly. Third, if your body weight starts to fall, food energy must be increased; if it rises, food energy should be decreased. However, if weight increases, check to see if body fat has also increased. If it has, you should eat less.

A logical approach is to decrease food intake by 200-500 kcal per day, while maintaining regular exercise programs, until you reach the desirable body-fat percentage. Reducing fat intake is the best nutrient-related approach to lowering body fat, but not to the point of exclusion. If you need to gain weight, add the above amount of food energy per day. However, if you are an athlete, increase food intake by 500-700 kcal per day, which will eventually lead to weight gain. Make sure that you have a good mix of carbohydrates, fats and proteins, as well as enough exercise training to ensure that any weight gain is mostly from lean tissue and not adipose (fat) tissues.