The Alkaline Diet – what’s it all about?

But when slight changes to our blood’s composition can actually be fatal, is this something that we want to achieve, or even can?

Let’s take a look at the alkaline diet and whether it’s all it’s cracked up to be. 

What is the alkaline diet?

When we eat or carry out any function in our body, there is metabolic waste.  Think of it like a car engine.  You put fuel in, and then you need an exhaust to get rid of the waste fumes. The alkaline diet is based on the idea that metabolic waste can be acidic, alkaline, or neutral.  If the metabolic waste is acidic, it can result in your blood becoming acidic and acidic blood is thought to result in disease.

This kind of diet proposes a range of foods to promote alkalinity in the blood, and therefore offset disease.

Can this really be achieved?

It is critical for your health that your blood pH remains constant.  If it were to fall outside the normal range, it could be fatal.  Actually, it is fatal. 

For this reason, the body has a number of ways to closely regulate this pH balance and it is known as acid-base homeostasis.  

Excreting acids through urine is one of the ways that the body regulates its blood pH, which is where part of this story becomes a little more accurate.  

Whilst the foods you eat can’t change your blood pH, they can change the pH of your urine.  If you eat a beef steak, your urine will be more acidic several hours later due to the composition of the metabolic waste of processing this food.  

Your kidneys play a key role in managing blood pH; for example, they produce bicarbonate irons that neutralise acids in your blood. When these bicarbonate ions bind to acids, they form carbon dioxide and are breathed out through the respiratory system. They also form water, which is then excreted when you go to the toilet.  

We also only have to consider the journey that food must go on when it enters the body.  In the stomach, food is covered in stomach acid, which, by definition is acidic.  The stomach has an average pH of 2-3.5.  Are foods still alkaline at this point?

Debunking Myths


Improving Kidney Health

The alkaline diet is thought to support kidney health and there is merit in this suggestion.  Raising urine pH may be of benefit as data suggests that the typical Western-style diet can be acidic which ultimately places an additional burden in cases of chronic kidney disease. (i)

Again, the note to make is that alkaline foods are altering urine pH, not blood pH.  

Preventing Cancer

The school of thought here is that cancer thrives in acidic environments, but there is no data to confirm this claim at present.  Cancer grows in normal body tissue which has an average pH of 7.4 and many clinical experiments have successfully grown cancer in alkaline environments.  

Whilst there is some theory around tumors growing faster in acidic environments, the cancer cells themselves create the acidity. (i)

The bottom line?

To date, there is no reliable data that suggests an alkaline diet lives up to the claims made, however, there is merit in the diet design.  

The alkaline diet suggests the inclusion of:

👉 fruits

👉 vegetables

👉 seeds

👉 legumes, such as lentils

We know there are a number of health benefits from the inclusion of fruit and vegetables in the diet, along with seeds and legumes. 

Fruit and vegetable consumption enhances well-being.  Largely due to their fibre content.  Fibre is what the (good) bugs in our gut adore!  Yes, you read that correctly.  Our gut is home to billions of bugs.  


Now when we usually think of bugs, we think they are bad for us, but we are host to both good bugs and potentially harmful bugs.  The good bugs keep the bad bugs in check and through their normal daily activities they contribute to a range of functions in our body.  They feed on the fibre that we eat as discussed before. As they ferment the fibre, they produce metabolites that talk to our brain and ultimately affect how we feel and behave.  This mechanism is known as the gut-brain axis and is bidirectional communication between our gut and brain – it’s also why we call our gut the second brain!  The gut and brain are like two peas in a pod; they also ride or die together; we can’t care for one without the other.  

In addition

When we fill up on fibre rich foods, we may be less likely to consume other food products, which could in fact be of detriment to our mood and well-being.

We also know that fruit and vegetable consumption is associated with a lower risk of all-cause mortality, particularly cardiovascular mortality.      

So, we know that fruit and veg is great for your body as well as your mind!

But the issue with the alkaline diet is that it suggests excluding groups of foods too:

👉 dairy products such as cheese and milk

👉 processed foods

👉 fish

👉 alcohol

👉 soda

👉 coffee

Some of these should be limited like we know how alcohol consumption can damage attempts at weight loss – remember protein and carbohydrates provide 4 calories per gram and fat provides 9 calories per gram, well alcohol provides 7 calories per gram! 

Processed foods are worth limiting in your diet; they are regularly linked to weight gain, mood disorders, diabetes, heart disease, and more.  The long and the short of it, there are no known benefits of eating processed foods. (i)

But excluding other food groups like dairy and fish can result in many nutrient deficiencies.  There may be valid reasons for excluding these food groups, like food sensitivities, but in this instance, nutritional supplementation may be appropriate.  

All things considered

A diet rich in variety is the best option for optimising your health.  It should include a range of proteins, grains, fruits, vegetables, vitamins, and minerals.  Removing any food groups can compromise nutritional status, especially without the guidance of a qualified practitioner.  

Whilst the alkaline diet doesn’t do much to change your blood pH (we have far more complex mechanisms to manage that), it does promote the inclusion of a range of plant-based foods, which we know to be beneficial to health.