With the off season approaching, it’s time to start thinking about making small changes that can help you to improve upon your 2015 running performances. One area that’s always good to strive to learn more about: diet.
On this topic, one of my pet peeves revolves around fad diets based on cool sounding pseudoscience that over-simplify what it actually takes to consume a well-rounded, complete, healthy diet. In reality, it’s a challenge to consume a diversity of fruits and vegetables, consume adequate but not excessive calories, jam in enough protein, etc. Even though this is a challenge, and sometimes seemingly impossible, it is not a reason to stop striving to achieve it.
I think that while most of us know this, when the going gets tough, these over simplified fad diets can suck some of us in.
The Alkaline Diet
One fad diet that at least partially falls into this category is the alkaline diet.
The premise of this diet is simple: replace “acid forming foods” with “alkaline foods” to improve health.
According to supporters of the alkaline diet, foods like meat, dairy, and eggs lower our internal pH (they are more acidic), while alkaline foods such as fruits and vegetables raise our internal pH (they are more basic) making us healthier for an array of reasons.
And how do they propose you measure your internal pH? Testing your urine! If your urine pH is low (acidic) that means your body is in an overall acidic state and you need to, as an example, stop eating meat and eat more vegetables!
Science of pH Balance
While this kind of sounds convincing, and while it’s cool to see urine pH go up and down depending on what we eat, it is very misleading to suggest that the pH of your urine is any indication of the pH of your body.
The pH of our blood, no matter what we eat, is kept within a very narrow range of 7.35-7.45 on the 0-14 pH scale. Urine pH generally varies from 4.6-8.0 (usually 5.5-8.0). If your urine is in this 5.5-8 range, you may or may not be healthy, and where you are on that range says nothing about how healthy you are, or the acidity of your blood.
There are internal mechanisms that our bodies use to buffer blood pH to keep it within that narrow healthy range, which Wikipedia does a great job of summarizing here. So if you are otherwise healthy, and have a urine pH of 6.5 or 8.0 or 5.9, your blood pH will still be within that 7.35 and 7.45 range no matter what.
Urine pH simply doesn’t indicate internal pH.
Is there any benefit this diet?
The scientific mechanism involving urine testing and the concept of altering internal pH that the alkaline diet relies on is faulty. That being said, does this mean we should totally throw out urine testing along with the dietary changes they encourage? Maybe not entirely.
First of all, it is important to note that what we eat DOES change the pH of our urine. Check out this study along with this one. What we know (in an somewhat unpredictable way) is that in an acute situation, if you consume lots of meats, cheeses etc, the acidity if your urine is likely to go up, while the opposite is likely true for fruits and vegetables.
Now remember, the acidity of our urine does not tell us anything about our overall health. In reality, it gives us a vague idea of what/if we just ate (influenced by other factors as this study and this one shows). In other words, testing your urine’s pH is kind of like a short-term, non-specific, messy diet log.
However, the one benefit I can see of this involves the notion that most of North American diets are heavy on the fats/processed foods, light on the fresh fruits and vegetables. So if somebody tests their urine, sees an acidic pH, and thus eats 2 salads/ day for a week, well that’s not a bad thing at all.
For instance, take a look at this study, which shows some of the benefits of an alkaline diet (including benefits to bone health, reducing muscle wasting, increasing growth hormone, and possible added benefits to chemotherapy agents). So if you eat more fruits and vegetables, good things happen to the average person.
It is important to note that this study did not evaluate with the urine pH test as their outcome measure. They merely evaluated the benefit of increasing alkaline foods. It even references studies that question the urine test’s validity, including this one on how urine pH does not predict bone health (despite mentioning how the alkaline diet improves bone health). In my mind, the study would have better been labeled “Eating enough fruits and vegetables improves health in the following ways…” because really that’s all they are saying. If to you an alkaline diet means increasing your fruits and vegetables, and not using urine pH as a guideline to evaluate and manipulate your internal pH, then that I can agree with!
The danger of pseudoscience leading to good outcomes
The danger of trusting the pseudoscientific basis for the alkaline diet: discovering an acidic urine pH value after a healthy meal involving much-needed needed “acid-forming” food (such as chicken breast) could falsely lead that individual to believing that they need to eat less of it (i.e. cut out chicken).
Yes, an acidic urine test value might pop up after you eat the chicken. Whether you need the protein or not, alkaline diet supporters would say this result indicates an over-acid state that needs to be corrected in part by eating less chicken. This is not good since as runners, depending on how much one trains, we need ~0.7-1g protein/lbs of body weight whether you have an acidic urine pH or not!
If you take the average North American individual, put them on an alkaline diet, will their overall health improve? Statistically, there’s a really good chance that the answer is yes, as it will make that individual eat more fruits and vegetables. Is the benefit because they altered the acidity in their body using urine pH as a valid indicator of internal pH? No.
Even though the alkaline diet may encourage many to be healthier, I really don’t see a difference between it and other more obviously damaging pseudoscientific fad diets. Another good example of one of these is dietary cleanses. For the type of cleanses I am thinking of, supporters say not eating for a day and drinking their shakes “cleanses and detoxes” the body, and leaves them feeling great while shedding pounds along the way. In reality, you are starving yourself, and thus losing weight due to being in a state of acute, non-sustainable, unhealthy caloric restriction.
Severe caloric restriction is obviously dangerous, and having your urine pH falsely tell you to eat less chicken can be too.
So when looking to make changes to improve your running next year, should you subscribe to the alkaline diet protocol? No. Should you try to eat enough fruits and vegetables? Definitely. Forget urine pH as an outcome measure, forget about trying to alter your internal pH, and stick to the diet log!