Veggie Blog

The old post argued that soy products offer plenty of healthy protein, so you can build big muscles without eating meat, and that there is a soy version of nearly everything. It is partly right, and here is what the research says.

What does soy offer?

According to Harvard’s Nutrition Source, soy is a nutrient-dense source of protein that can be eaten several times a week, especially in place of red and processed meat. Soy protein is a complete protein, with all nine essential amino acids. Harvard’s table gives the protein content of common soy foods: one cup of soy milk has 7 grams, three ounces of soft tofu 8 grams, half a cup of boiled edamame 11 grams and three ounces of cooked tempeh 13 grams.

Can you build muscle on soy?

Yes, as long as you train and eat enough protein overall. A 2018 meta-analysis of nine studies with 266 participants found that soy protein supplements produced similar gains in strength and lean body mass during resistance training as whey protein, and the studies lasted at least six weeks. Training is what drives the gains, and the protein is the building material. For more, see our post on supplements for building muscle.

Is soy safe?

For most people, yes. Harvard says that the fears that soy causes breast cancer, thyroid problems or dementia have not been substantiated, and that soy can safely be eaten several times a week. It adds that the type of soy matters, because whole soy foods, protein powders and soy burgers differ, which makes blanket statements hard. If you have a thyroid condition or take medication, ask your doctor or dietitian about soy.

What about soy products that imitate meat?

The old post celebrated soy “chicken” and other imitations. They can be convenient, but they are usually more processed than tofu or tempeh, so read the label for salt and added ingredients. The old post also asked about animals and the climate: our post on vegetarianism and the environment looks at the evidence.