The zone diet and athletic performance.

Area of Science:

• Sports Nutrition
• Exercise Physiology
• Endocrinology

Background:

• The Zone diet (40% carbohydrates, 30% protein, 30% fat) is marketed to enhance athletic performance by altering hormonal responses.
• It proposes increased vasoactive eicosanoid production for improved oxygen delivery to muscles, contrasting with traditional high-carbohydrate sports diets.

Purpose of the Study:

• To evaluate the scientific validity of the Zone diet's claims regarding athletic performance enhancement.
• To assess the impact of the Zone diet's macronutrient composition on hormonal milieu and eicosanoid production relevant to exercise.

Main Methods:

• Analysis of existing peer-reviewed literature on the Zone diet, sports nutrition, and hormonal responses to macronutrient intake.
• Critique of the proposed mechanisms linking the Zone diet to improved athletic performance, focusing on hormonal and eicosanoid pathways.

Main Results:

• The Zone diet is characterized as low-carbohydrate and calorie-deficient, contradicting established sports nutrition principles.
• Available evidence does not support the Zone diet's ability to favorably alter pancreatic hormone response or significantly contribute to active muscle vasodilation via eicosanoids.
• The key eicosanoid implicated in the Zone diet's proposed benefits is not found in skeletal muscle.

Conclusions:

• The Zone diet's purported benefits for athletic performance are not supported by robust scientific evidence.
• The diet's macronutrient distribution and proposed hormonal mechanisms are unlikely to enhance, and may potentially impair, athletic endeavors.
• The Zone diet is considered potentially ergolytic rather than ergogenic for athletic performance based on current scientific understanding.