Protein Is Not Protein: Amino Acids, the Starck Factor, and What Your Body Actually Does With What You Eat

In this episode of The Signal, host Andy Feltovich sits down with Dr. Carlene Starck — proteinbiochemist, metabolic nutrition scientist, and founder of Starck Science. Carlene holds a PhD inBiochemistry from Massey University, spent her postdoctoral years at the Hospital for SickChildren in Toronto, and trained under two of the giants of protein metabolism research:Professor Paul Moen and Dr. Robert Wolfe. She recently published a landmark factorial modelof amino acid requirements in the Journal of Nutrition — a paper nine years in the making. Thisconversation starts with a provocation: the gram of protein you ate and the gram of protein yourbody used are not the same thing. And most of what you think you know about protein qualitystops exactly where the interesting science begins.What You’ll Learn:• Why protein quality scores like DIAAS are a useful step — and where they stop tellingthe story: first-pass metabolism, liver handling, and what ‘utilization’ actually meansbeyond the gut wall• The Starck Factor: the practical conversion rate between essential amino acidsupplements and whole protein targets — and why the ratio is not 1:1• Glycine — the smallest amino acid and the most overlooked: why the factorial modelfound it may have the largest obligatory losses of any amino acid, including the essentialones, and what that means for glutathione production, methylation, and the real reasoncollagen supplementation might actually work• How amino acids build more than muscle: tryptophan, tyrosine, serotonin, dopamine,and the cognitive case for protein that nobody is making loudly enough• Why catabolism is just as important as anabolism — and why resistance training’s mostimportant job may be the constant remodeling and quality control it runs on your body’sentire protein inventory• The plant vs. animal protein debate, stripped of ideology: what the science actuallyshows about digestibility, amino acid composition, and why ‘you can get everything fromplants’ is true — with an asterisk that matters• Fiber: what it actually does (digestive health, gut lining integrity, short-chain fatty acids),what it doesn’t do (the observational associations are heavily confounded), and whyfibermaxxing may be solving the wrong problem• Bioactives and phytonutrients — the final frontier: why the colors of your vegetables aretelling you something, why isolating them tends to fail the same way isolatingantioxidants did, and why the answer keeps coming back to the whole food• The politics of protein: why a landmark model took nine years to publish, howinstitutional inertia keeps outdated requirements in place, and what actually has tochange for the science to catch up with the evidenceIf you’ve ever tracked protein grams without asking what your body does with them — orwondered whether the plant-based protein on your shelf is doing what the label implies — thisepisode will change how you think about the question. The science is more complicated thanthe guidelines. It’s also more actionable.Guest Links:Starck Science: starckscience.comLinkedIn: https://www.linkedin.com/in/drcarlenestarck/