Effects of a Vegan Diet on Body Composition, Performance, and Menstrual Cycle

A 12-week controlled trial.

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This study investigated the impact of transitioning from an omnivorous to a vegan diet on body composition, physical performance, and menstrual cycle in young, recreationally trained women over 12 weeks. It aimed to explore the challenges of adopting a vegan diet and its short-term effects on trained women.

PMID: 39663646

Key Points

• Aim: To examine how an 8-week vegan dietary intervention affects body composition, performance (squat and countermovement jump), and menstrual cycle in recreationally trained women transitioning from an omnivorous diet.

• Participants: Ten healthy women (aged ~24 years) with at least two years of strength training experience.

• Methods:

  • A 12-week controlled trial divided into a 4-week omnivorous phase and an 8-week vegan phase.

  • Participants received guidance on balanced diets but were responsible for independently maintaining macronutrient intake.

  • Measurements included body weight, skeletal muscle mass (SMM), fat mass, squat performance, countermovement jump height, and menstrual cycle tracking.

• Results:

  • Protein intake decreased significantly during the vegan phase (from 1.39 g/kg BW to 1.06 g/kg BW).

  • Carbohydrate consumption increased significantly.

  • Body weight and skeletal muscle mass slightly decreased during the vegan phase.

  • Squat performance remained unchanged, but countermovement jump height decreased.

  • No significant changes were observed in menstrual cycle hormone concentrations.

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