The Mediterranean diet (MD) pattern is widely acknowledged by the scientific community as a healthy one.1-3 Ancel Keys, an American biologist and nutritionist, was the first to describe the MD as a combination of eating habits traditionally followed by individuals in the olive-growing areas bordering the Mediterranean Sea characterized by a low saturated lipid diet that was conveying protection against coronary heart disease by lowering plasma cholesterol levels.4 Its health and preventive effects are probably related in part to a high intake of food rich in bioactive compounds (such as polyphenols, phytosterols, and carotenoids) mainly present in vegetables, fruits, nuts, whole grains, and legumes that may have anti-inflammatory effects owing to their antioxidant profile. Also, the MD's characteristically has a low content of meat and meat products and regular intake of fish may help to lower risks.5-7 Carbohydrates and lipids are the principal sources of energy intake (around 30%-40% of total energy intake from lipids and 50%-60% from carbohydrates). Proteins contribute less than 20% of total energy intake (around 10%-15% of calories). It is clear that the relationship between the different macronutrients characterize the MD more than any each single food isolated from the whole. In particular, the protein-carbohydrates ratio can vary from 1:3 to more than 1:6. However, in its original form, the MD was not only a food pattern but a "way of life," which includes regular physical activity.8 Athletes can be considered as part of the population most exposed to oxidative stress simply due to the higher level of physical activity.

Therefore, could the MD be a good choice for athletes?

When scientists talk about sports nutrition, one must consider the type of sport and the volume of training. In general, people who are involved in training sessions shorter than 60 minutes per 3 to 4 times a week should have a carbohydrates intake of 3 to 5 g per kg of bodyweight daily.9

Athletes involved in high volume (2-3 h/d of exercise performed 5-6 days per week) of moderate to vigorous intensity (65%-80% VO_2max) training should consume at least 5 to 8 g/kg per day of carbohydrates to restore muscle and liver glycogen consumed. Athletes involved in training programs that include a combination of moderate to vigorous intensity (65%-85% VO_2max), repeated bouts of exercise per day (1-2 sessions per day) over an extensive time frame (3-6 h/d), and workout 5 to 6 d/wk (as is common with elite athletes) need to consume a higher amount of carbohydrates, on average 10 g/kg per day, in some cases up to 12 g/kg per day, depending on the athlete and the activity.10,11 Athletes need to consume high amounts of carbohydrates daily as well as adequate amounts of fiber to maintain glucose homeostasis; thus, most dietary carbohydrates should come from whole grains, vegetables, fruits, and so on.

The timing of meals has also been studied. Carbohydrates eaten many hours before exercise have been shown to increase carbohydrate oxidation, decrease the perception of fatigue, and in general improve performance.12 During long sessions of exercise training (2-3 hours) 60 g of carbohydrates are oxidized every hour, on average 1 g every minute.13 There are specific recommendations for exercise or competition longer than 60 minutes that include 1 to 4 g of carbohydrate/kg of body weight in the 1 to 4 hours before activity.14

The MD food pattern is an overall food pattern characterized by high consumption of plant-based foods such as vegetables, legumes, fruits, nuts, and nonrefined cereals as main source of carbohydrates (such as whole grain bread, whole-grain pasta, brown rice) that fits well with the exercise research.15

Regarding fat, the ratio of the beneficial monounsaturated to the nonbeneficial saturated lipids is high compared with total daily fat intake. Several studies have shown how the adoption of the MD can improve antioxidant defense and fight oxidative stress induced by heavy physical activity.16,17 Moreover, recent studies show how the n-3 polyunsaturated fatty acids (PUFAs) attenuate blood markers of muscle damage (skeletal muscle slow troponin I, myoglobin, creatine kinase), inflammation (tumor necrosis factor [alpha]), and delayed-onset muscle soreness.18 For this reason, a high intake of n-3 PUFAs has been recommended for athletic populations by some authors.19 Interestingly, the MD is high in n-3 PUFAs because it includes regular consumption of fish.

Although the theory is controversial, some studies report that different types of dietary fat elicit different effects on mitochondrial health and that a diet high in saturated fatty acids promotes mitochondrial dysfunction associated with increased oxidative stress, whereas a diet rich in n-3 PUFAs improves mitochondrial function.20,21 Oxidative stress reflects an imbalance between production of reactive oxygen species (ROS) and the antioxidant defense. Regular physical activity improves antioxidant defenses, but acute and strenuous bouts of aerobic and anaerobic exercise can induce ROS overproduction. Indeed, this ROS production is important because it modulates the skeletal muscle contractile function and promotes the mitochondrial biogenesis and the normal skeletal muscle restoring postexercise.22 An adequate intake of micronutrients through a balanced diet is the best way to maintain an optimal antioxidant status.23 The MD includes fat and foods rich in compounds with important antioxidant properties, such as the tocopherols, carotenoids, and several phenols.24

Regarding protein intake, the International Society of Sports Nutrition has identified a range of intake from approximately 1.4 g/kg per day (for endurance athletes) to 2.4 g/kg per day (strength/power athletes) of proteins, which allows optimizing exercise training-induced adaptations.25

According to the recommendations of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine, the dietary protein intake for athletes ranges from 1.2 to 2.0 g/kg per day, which is slightly lower than the protein intake proposed by the International Society of Sports Nutrition on average. Protein intake should be divided during the day in order to provide a constant supply of high-quality proteins,26 especially at the end of training sessions to maximally stimulate muscle protein synthesis.11,27 For active people who practice resistance training for 3 to 4 times a week, it appears that a protein intake of 1.25 g/kg per day is sufficient to compensate for the enhanced muscle protein degradation during prolonged training sessions.28

Further, the MD has a flexible protein to carbohydrate ratio (from 1:3 to 1:6 or more) that can be adapted to the type of sport practiced and built to satisfy the specific nutritional needs of each athlete following the international guidelines.

Our conclusion is that the MD diet pattern can easily be adapted to the needs of athletes. However, at the moment, there is no scientific evidence that shows how the adoption of the MD can have short-term effects on performance. Therefore, more studies are needed on this topic.

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