The Alkalinity Diet

Vani Hari (aka "Food Babe") is the latest in sell-ebuties (thanks Kevin Faulta) who are capitalising on the human instinct of fear to drive associated sales and self promote.

She is somewhat my muse for this topic – the myth surrounding acidity and alkalinity of the body, which was re-highlighted in her absolutely crazy rant about babyfood on facebook recently.

Here I was thinking that once the founder of this crackpot theory had been arrested it would have died an early death – wrong. So it's debunking time.

What is the theory?

Let’s take a step back to basic chem class…no snoozing!

Substances can be acidic or alkaline based on their pH. Acid substances have a pH of below 7 whilst alkaline (or basic) substances have a pH of more than 7.

Traditionally we’ve used this scale to talk about chemicals in test tubes, but recently it has been discussed in terms of the food we eat. Everything around us is made of chemicals, including our own body, so it is unsurprising that food (which is also made of chemicals) has a pH level.

Now as this theory goes, the pH level of a food doesn’t matter so much as the residue it leaves in the body. So some foods may be acidic in nature, but leave an alkaline residue.

As with most food scams there is a hint of truth in them. This is what proponents latch on to to justify that the claim in its entirety is true.

What is this residue??

What foods cause an ‘acidic’ residue and which leave an ‘alkaline’ residue?

It is not unusual that these bogus theories fall at the first hurdle. What is surprising is that many people don’t see this as a red flag. This part of the theory falls down in two ways.

First, there are many lists put out by proponents of this diet, and quite a few contradict themselves.

Second, none of the lists provide verified scientific evidence to back up why that food leaves an acidic or alkaline residue.

Hmmm. What does the science say?

Yes food does leave a residue! However we hardly ever eat a single component of a food in isolation (Vitamin C for eg) and as such foods tend to even out over a meal. Second - and this is most important, our body is well equipped to handle the pH of food remnants in our system.

Let’s keep going…

Yes, but do acidic foods harm us??

This theory rests on the concept that you want your body to be alkaline to ward off nasties such as cancer and osteoporosis.

This is quite easily false.

Many different body systems have varying pH levels. Your stomach, for example, is wonderfully acidic – and this is great! You wouldn’t be able to digest your food without your stomach having a pH somewhere near 2 (strongly acidic).

Other parts of your body are acidic to stop harmful bacteria and yeasts growing inside of them.

Surely this theory is able to prove sugar is pure evil?

One of the common devil foods at the moment has still not escaped persecution here either. Sugar has been deemed as leaving acidic residue.

Again quite easily false.

Sugar has a neutral pH, however as with any other substance, when mixed with other foods the overall pH will change.

Right, but doesn't this food affect blood ph?

And here is the crux of the issue – you can change your blood’s pH.

Now what I fail to understand is how proponents of this diet can keep peddling this without ever actually questioning the sheer stupidity of this statement. It does speak to their complete lack of medical and nutritional knowledge however.

Of note, I have seen people shifting away from speaking of blood pH to now speaking of tissue pH (this is yet another tactic of scams). The reason for this shift is that quite obviously blood pH is stable.

Anyone whose blood pH deviates from approximately 7.4 – even by a small amount – would need to be hospitalised to prevent death. As such your kidneys and other organs work really well to ensure this does not ever happen.


Again so many wrongs with this statement.

If it were true then we would all have stomach and vagina cancer (two very acidic parts of our body). If this were true we would be able to alter our body’s pH (see previous debunk). If this were true no one would have cancer or the blood as it is an alkaline 7.4 ALL THE TIME. *Unless you have a serious medical condition require hospitalisation.

The hint of truth behind this claim is that indeed some cancers do seem to grow faster in acidic environments.

However this proponents of this theory form a slightly back to front argument. What science is showing is that cancer itself produces the acidic environment which promotes its growth, not that the acidity of the body is causing the cancer.

In that cancer forms quite happily in alkaline environments (this has been proved in numerous high level studies – see links below), but then excretes acidic compounds which it can feed on…and most importantly can’t be influenced by the food you eat.

Yes but isn't this causing stress on our body leading to it having to leach calcium from our bones to make our blood pH 7.4?

Again, this couldn’t be further from the truth. The idea behind this myth (it really is a myth inside of a massive myth) – is that the body leaches calcium due to its alkaline properties to help neutralise the acidity of the body.

There are huge issues with this theory. I would like to start out by saying there is absolutely no evidence to suggest this happens in the body.

So how does the body regulate acidity?

Well the kidneys are the integral part to this process.

They release bicarbonate ions which neutralise acidity in the body. The respiratory system is also crucial in this process, breathing out the bi-product of this process – carbon dioxide, the other bi-product being salt which leaves the body in urine.

In fact one of the main drivers of osteoporosis is the loss of collagen from bones. This loss can actually be amplified by low acidity diets – as protein is one of the key factors in bone strength and regrowth.

So why do I have an acidic pH when I pee on that stick??

Urine pH is simply not a reliable measure of blood pH. There are two reasons for this;

As previously stated different parts of our body have different pH levels (for good reason).

Part of the process of excreting the acidity from foods is through urine - so if you eat food with protein for example (acidic residue) they will always make your pee have a lower pH. This process is completely normal and very natural.

How to spot a fake claim?

Ask yourself: Is there something being sold with it? Are there accessible peer reviewed (preferably meta-anlysis) studies supporting this belief?

Enter “Alkaline Water”. This miracle substance is said to make your body more alkaline, cleaning up the damage from acidic foods.

Errm okay.

So I guess there has been high level, peer reviewed, research done to back up that amazing claim right?

Ah nope.

In reality alkaline water is no different to the hydrogenated water fad doing the rounds. Save your money on this get rich quick scheme and donate it to charity instead. Perhaps a cancer research center or safe drinking water project are good places to start.


Leave a comment