Does the alkaline diet stack up?

Promising weight loss, reduced inflammation and more, the alkaline diet has been spruiked worldwide. But what do the experts say?

The alkaline diet, also known as the alkaline ash diet or the acid-alkaline diet, is touted as a way to improve health, reduce inflammation and treat a range of chronic health conditions.

Advocates believe that avoiding acid-promoting food reduces inflammation in the digestive system leading to an overall improvement in health, and its fans include Gwyneth Paltrow, Victoria Beckham and Elle Macpherson.

What is the alkaline diet?

The alkaline diet works on the premise of maintaining an “optimal” pH level in the body.

Proponents claim that because the body’s blood is slightly alkaline (ranges between 7.35 and 7.45), people should eat alkaline foods.

Alkaline foods include selected fruits and vegetables, nuts and legumes as well as foods regarded as “neutral” such as certain fats, starches and sugars.

Foods characterised as “acidic” are minimised or forbidden – including meat, poultry, fish, eggs, milk, cheese, yoghurt, grains and alcohol.

What do experts think about the alkaline diet?

Nutritionist Rosemary Stanton warns the alkaline diet is not based on science.

“It is vitally important for the pH of the blood to remain within the limits, but that is controlled by the kidneys and respiratory system,” Dr Stanton says.

She says it’s not possible for a style of eating to change your body’s pH levels.

“Its authors appear not to understand how the body’s pH regulation works and the claims they make about their alkaline diet being good for cancer, bone health etc are not valid,” she says.

Dietitians Australia spokesperson Joel Feren says there have been no clinical trials to date to test the validity of the alkaline diet.

“For most people there’s no need to restrict healthy foods, use supplements and alkalise your water, or to remove whole food groups from your diet,” he says.

What are the dangers of the alkaline diet?

The experts warn eliminating whole foods can lead to nutritional deficiencies.

Dr Stanton says a lack of protein is particularly bad for children, teenagers and over 70s.

“The lack of nutritious grains also means some types of dietary fibre will be missing and this can have adverse effects on the ‘good’ bacteria in the intestine,” she says.

Dr Stanton says while cutting out large food groups may lead to initial weight loss, the diet would be hard to follow for life – so the weight would return once previous eating habits resume.

Joel says there is no need to avoid dairy, grains, or legumes unless you have a recognised allergy or intolerance.

“These are all nutritious foods, and without them, it’s likely your diet will be low in important nutrients like calcium, B vitamins, and fibre,” he says.

He says cutting out red meat and whole grains could lead to iron deficiency, while shirking calcium-rich dairy foods can increase the risk of osteoporosis.

“While you don’t have to include dairy in the diet, you must compensate by eating a range of calcium-rich foods,” he says.

Studies have found no evidence an alkaline diet protects bone health.

Joel also says overly restrictive diets can also lead to poor relationships with food.

Dr Stanton says the diet can even be dangerous for sick people who put their faith in the diet instead of medical treatment.

A Canadian study found claims the alkaline diet can prevent or treat cancer have no scientific backing. Unfounded claims landed alkaline diet book author Robert Young in trouble after he admitted he had no medical or scientific qualifications.

So does the alkaline diet have any benefits at all?

Despite the alkaline diet’s shortcomings, the experts agree there are a couple of good take-aways.

Increasing your fruit and vegetable intake is a big plus, says Joel, while Dr Stanton points out that restricting your processed food intake is also beneficial.

A 2020 study found Aussies whose diets included large amounts of processed food were 61 per cent more likely to be obese.

Written by Bianca Carmona.