been shown to consume significantly fewer calories compared with eumenorrheic athletes (14) while similar energy intakes between
the two groups have been reported as well (15). Specific nutrients,
such as fiber, protein, calcium, colecalciferol, and vitamin K, have
been shown to contribute to menstrual irregularities and low bone mineral density, also producing conflicting results (4, 16). Only
little evidence exits up to now to support the hypothesis that dietary deficiencies, in particular calcium intake, favor osteoporosis in
healthy recreational and professional athletes, even though abnormal and restrictive eating behaviors seem to be related to a larger
probability of fractures (17).
From a practical perspective, the exact energy requirement of
an athlete is not easy to quantify but a general consensus exists
on the minimal energy availability needed for a female athlete
(8). This is the energy required for living in a healthy way without
taking the energy spent during physical activity into account. The
energy available is therefore the total energy intake brought by
nutrition minus the energy spent during physical activities. The
target for an athlete should be at least 45 kcal/kg of fat free mass
per day (Table 1). Concretely for an athlete of 50 kg having a fat
percentage of 15% and a fat free mass of 42.5 kg, the energy available should be above 1900 kcal/day. Having an energy expenditure of 500–600 kcal during sport activities would increase the daily
total energy intake to 2400–2500 kcal.