Thanks to Mark Sisson for explaining this rationally so I don’t have to…
What’s up with the alkaline diet?
When we metabolise foods, we produce metabolic waste products of various pH levels. Foods like meat, fish, grains, legumes, and dairy generate what’s called an acidic ash, and they’re often lumped together under the label of “acid-forming foods.” Many proponents of the alkaline diet argue that regularly eating these foods causes the body to become chronically acidic, leading to bone loss, poor performance, and degenerative disease.
But here’s what’s actually true.
Your Body Regulates Blood pH on Its Own
The body has multiple overlapping systems for regulating pH. First, there’s respiration. The lungs maintain blood pH by modulating how much carbon dioxide (CO₂) we exhale. This is instantaneous and incredibly precise.
Then there are the kidneys. They excrete hydrogen ions when the body’s too acidic and regenerate bicarbonate ions to buffer the blood. This takes a little longer, but it’s highly effective.
As long as your lungs and kidneys are functioning properly, the pH of your blood doesn’t budge. It doesn’t matter what you eat. Yes, eating more meat can make your urine more acidic, but that’s proof your kidneys are doing their job and offloading the excess acid.
Chronic acidosis, the kind that alkaline diet proponents are talking about, only happens when these systems fail. These failures don’t happen because of “increased acidity” from grass-fed steaks and yogurt. Instead, they’re caused by untreated diabetes, alcohol abuse, and other serious maladies.
Acidic Diets and Bone Health
The other big claim is that acid-forming diets leach calcium from the bones in an attempt to buffer the acidic load. This sounds plausible at first. Studies show that urine calcium increases after eating protein. Peeing out calcium sounds bad, right?
Yes, eating protein increases urinary calcium, but it also increases calcium absorption in the gut. The net effect is neutral, or even positive, for bone health. You’re not peeing out bone calcium. You’re urinating out the excess calcium that the protein helped you absorb.
We know this because real-world studies consistently show that higher animal protein intake improves bone mineral density and reduces fracture risk, especially when paired with adequate calcium. It helps that most of the protein-rich foods we recommend, like meat, eggs, dairy, and gelatinous bone broth, also come bundled with the very nutrients you need to metabolise and buffer any acid they generate.
What About People With Compromised Kidneys?
Here’s where the concern might be warranted. People with kidney disease or declining renal function do have a reduced ability to excrete acid. That can lead to low-level acidosis and real consequences.
However, in people with healthy kidneys, adding “extra” animal protein actually improves kidney function and makes it even easier to buffer acidity by providing ammonia substrates. The alkaline diet people would predict the opposite, and they would be entirely wrong.
A Rant About Biohacking pH
The alkaline diet crowd ultimately believes they can improve upon millions of years of human evolution and physiological development by top-down micromanaging your acid-base balance.
Like every other group that tries to wrest control of an incredibly intricate system, this will end badly. You don’t outsmart your kidneys. You support them with a nutrient-dense diet and trust them to do their job.
Sodium Bicarbonate for Performance
There is one valid use case for “alkalising” your body: intense training. One of the most consistent findings in sports nutrition is that taking sodium bicarbonate (baking soda) before a workout improves performance, power output, and endurance. It buffers the acute acidity that builds up during intense exercise, delaying fatigue.
The sweet spot seems to be between 0.2 and 0.4 grams per kilogram of bodyweight. Too much can cause bloating, nausea, and full-blown GI distress.
Final Thoughts
You can’t alter your long-term blood pH through diet. If you could, you’d be in the ER. If the alkaline diet helps someone eat more whole foods and vegetables, that’s a win. But it’s not because they’re “neutralizing acid” in their bloodstream—and since they’re also omitting meat, seafood, dairy, and eggs, they’re actually worsening their nutrient intake.
If you’re worried about acidity dissolving your bones, focus on mineral intake—magnesium, potassium, calcium, and sodium—and getting enough quality dairy and animal protein. Don’t avoid steak because someone on Instagram told you it turns your bones into chalk.
It’s total nonsense, and the opposite is true.