Subscribe to NutritionFacts.org’s free newsletter to receive our B12 infographic that covers the latest research takeaways and Dr. Greger’s updated recommendations: https://nutritionfacts.org/subscribe/ DESCRIPTION: Lower levels of the cancer promoting growth hormone IGF-1 in those eating vegan is not expected to affect their accumulation of muscle mass. Why might we want low levels of IGF-1 in adulthood? See IGF-1 is a One Stop Cancer Shop (http://nutritionfacts.org/video/igf-1-as-one-stop-cancer-shop/). As we saw in How Plant-Based to Lower IGF-1? (http://nutritionfacts.org/video/how-plant-based-to-lower-igf-1/), vegan men have higher testosterone levels, which can be a risk factor for prostate cancer and enlargement, but given the average IGF-1 levels of those eating plant-based diets this may not be an issue. See Ex Vivo Cancer Proliferation Bioassay (http://nutritionfacts.org/video/developing-an-ex-vivo-cancer-proliferation-bioassay/) and Prostate vs. a Plant-Based Diet (http://nutritionfacts.org/video/prostate-versus-a-plant-based-diet/). Having said that, if they eat excess “high quality” protein, they may not retain their IGF-1 advantage. See Higher Quality May Mean Higher Risk (http://nutritionfacts.org/video/higher-quality-may-mean-higher-risk/), Animalistic Plant Proteins (http://nutritionfacts.org/video/animalistic-plant-proteins/), Too Much Soy May Neutralize Benefits (http://nutritionfacts.org/video/too-much-soy-may-neutralize-plant-based-benefits/), and How Much Soy Is Too Much? (http://nutritionfacts.org/video/how-much-soy-is-too-much/). Have a question for Dr. Greger about this video? Leave it in the comment section at http://nutritionfacts.org/video/plant-based-bodybuilding/ and he’ll try to answer it! Image Credit: Dan Bennett, dbking and Larry He’s So Fine via Flickr; alanpoulson via Shutterstock; auremar via Fotolia; Derek Tresize by Josh Avery, Ed Bauer and Nathane Jackson via veganbodybuilding. Images have been modified. https://NutritionFacts.org • Subscribe: https://nutritionfacts.org/subscribe • Donate: https://nutritionfacts.org/donate • Podcast : https://nutritionfacts.org/audio • Facebook: www.facebook.com/NutritionFacts.org • Twitter: www.twitter.com/nutrition_facts • Instagram: www.instagram.com/nutrition_facts_org • Books (including the NEW How Not to Diet Cookbook): https://nutritionfacts.org/books • Shop: https://drgreger.org