The American Journal of Clinical Nutrition
Self-selected vegan diet reduced muscle in older adults
Thigh muscle volume fell 0.61 liters on the vegan diet versus 0.01 liters on the omnivorous diet over 12 weeks.Thigh muscle volume fell 0.61 liters on the vegan diet versus 0.01 liters on the omnivorous diet over 12 weeks.

Randomized trial · 72 peopleVegan diet
Who was studied72 healthy older adults, 12 weeks, against adults following an omnivorous diet
What changedThigh muscle volume fell 0.61 liters on the vegan diet versus 0.01 liters on the omnivorous diet
The catchProtein intake also fell, so the trial cannot isolate effects of excluding animal foods