Yes, There's Pea Protein in Our Chili. Here's Why I'm Good With That.

A note from Rip Esselstyn, Founder of Plant Strong

Some of you have asked me about the pea protein we added to our chilis and the soy protein in one of our granolas. I love that you're reading labels. So let me tell you why I'm comfortable with both.

A lot of the worry comes from The China Study, and I get it. I've cited Colin Campbell's protein research myself. His landmark experiments gave rats a powerful liver carcinogen and then fed them casein, the main protein in cow's milk. Rats fed a 20% casein diet developed roughly six times as many precancerous lesions as rats fed 5% casein (Appleton and Campbell, 1983). That work was done in rats exposed to a carcinogen that ate casein as their only protein.

So what happens when people eat isolated pea and soy protein, the same kind in our foods? Let’s start with the big one: cancer. Researchers gave men at high risk of prostate cancer recurrence a daily shake made with 20 grams of soy protein isolate, or a placebo shake, for up to two years. In both groups, the cancer came back at almost exactly the rate researchers predicted before the study began (Bosland et al., 2013). The soy isolate showed no sign of feeding the cancer.


The news for women is just as good. Postmenopausal women who took soy protein every day for three years had no thickening of the uterine lining and no rise in precancerous changes or cancer (Quaas et al., 2013). A review of eight trials found that isoflavones didn't change breast density, a well-known marker of breast cancer risk, in postmenopausal women (Hooper et al., 2010). Survivors can take heart too. In a study of 9,514 survivors in the US and China, women who ate the most soy had a 25% lower risk of their cancer coming back than women who ate the least (Nechuta et al., 2012).

And pea protein? It isn't a meaningful source of the isoflavones that put soy under the microscope, and we couldn't find a single human study suggesting it raises cancer risk.

The rest reads like a highlight reel. A review of 46 trials in postmenopausal women found that isolated soy protein lowered LDL cholesterol (Moradi et al., 2020). Soy didn't budge testosterone or estrogen in men across 41 studies (Reed et al., 2021). Pea protein built muscle as well as whey in a 12-week strength-training trial (Babault et al., 2015).


So why add protein at all? In 12 years as a firefighter, I never answered a call for protein deficiency, and I still get mine from oats, beans, greens, and brown rice. After 60, though, the game changes. Muscle and strength quietly slip away with age, and that decline predicts falls and lost independence. Experts recommend that adults over 65 get 1.0 to 1.2 grams of protein per kilogram of body weight daily (Bauer et al., 2013). A little pea or soy protein makes that target easier to reach, and can help protect our muscle mass, especially when paired with strength training.

Our chilis are still built on beans and vegetables, and our granola is still made from whole grains. Keep the questions coming. That's how we all stay Plant Strong.

-Rip