The Alkaline Diet (aka the pH diet, acid-alkaline diet), is one of the latest eating plans to have gained popularity amongst celebs and Instagrams. Some say that by replacing acid-forming foods with alkaline foods you can reduce weight, curb inflammatory conditions and even help to overcome cancer. So what’s the go?


What is it?

The basic premise of the alkaline diet is that what a person eats can influence the pH of their blood. It suggests that certain foods can influence how much compensating the body has to do in response to eating the particular foods. For example, when we indulge in too many acid-forming foods, the body then has to work harder to neutralize the pH, mainly by releasing alkalising minerals into the blood to buffer the acid.

  • Acid-forming’ foods: meat, rice, pasta, bread, cheese, soft drink, alcohol, coffee and sugar.
  • ‘Alkalising’ foods: most fruits and vegetables, almonds, chestnuts, tofu, herbal tea, some seeds and apple cider vinegar.

The diet encourages its followers to achieve an alkaline state and a ratio of 80:20 (alkaline to acidic foods) is recommended.


What are the claims?

The diet is based on the theory that acid forming foods place stress on the body leading to weight gain, inflammation and ultimately acidosis (increased blood and tissue acidity). Followers believe that we can ‘alkalise’ our bodies by consuming a greater proportion of alkaline foods. The diet claims it can help protect bone density and muscle mass, lower risk of hypertension and stroke, lower inflammation, assist with weight loss.


What does the science say?

The pH of human blood is very tightly regulated to stay within the narrow range of 7.35 to 7.45, making it slightly alkaline. No foods can influence your blood pH, otherwise it could be fatal.

  • pH 0 – 7 = acidic
  • pH 7 = neutral
  • pH 7 – 14 = alkaline

After eating certain foods, whether they are acidic or alkaline, your stomach acid, gall bladder, liver and kidneys will naturally maintain the this pH within a very tight range. Those partaking in this diet often measure their urine to determine the pH level (aiming for their urine to be alkaline). The flaw with checking the pH of urine is that it is not correlated to the pH of the blood. In fact the pH of your urine changes, depending on what you eat – that’s how your body keeps the level in your blood steady (for example if you eat a large steak, your urine will be more acidic as the body is  ensuring it’s pH stays within a healthy range). The other important thing to understand is that pH levels differ greatly in different parts of our body. Your stomach is very acidic (pH 3.5 or below) so it can break down food.



Bottom line

The idea that a food can be acid or alkaline is irrelevant because the human body regulates this. Nothing you eat is going to substantially change the pH of your blood. Your body works hard to keep that level constant. With the myriad of health advantages offered by a diet rich in fresh vegetables and minimally processed foods it’s impossible to argue with this positive message that the diet promotes. Additionally, avoiding sugar, alcohol and processed foods is healthy weight loss advice too. However, the Alkaline diet severely limits many important foods such as dairy, meat, poultry and restricts grains and fruit, which can result in some nutrient deficiencies and make it difficult to maintain long term.

Let us know if you would like us to write about any other diets or food trends! For more of our nutrition blogs, click here.

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