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- There is no scientific evidence to support the alkaline diet's purported health benefits.
- The alkaline diet focuses on eating foods with low acidity.
- Cutting out as many food groups as the diet recommends can lead to nutritional deficiencies.
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The alkaline diet has become a trend among celebrities like Gwyneth Paltrow, Jennifer Aniston, and Tom Brady as a way to lose weight, boost energy, and prevent disease.
But like most things that sound too good to be true, the alkaline diet is a prime example. Experts say there is no scientific evidence behind the idea that alkaline foods are healthier than acidic ones.
"It is not based on anything besides anecdotal evidence at this time," says Tracy Lockwood Beckerman, a registered dietitian in New York City.
The alkaline diet is pseudoscience
The idea behind the alkaline diet is that the foods you eat can change your blood pH level and thus change your health.
All you have to do is avoid foods that the diet categorizes as acidic, limit neutral foods, and focus on more alkaline foods. The alkaline diet categorizes foods according to pH as follows:
- Acidic: Meat, fish, dairy, eggs, grains, alcohol
- Neutral: Natural fats, starches, sugars
- Alkaline: Fruits, nuts, legumes, vegetables
And while the foods you eat can affect the pH of your urine, this is not the same as changing your blood pH. Your blood pH level stays close to neutral at around 7.4, and you cannot shift your overall blood pH through your diet, as the alkaline diet suggests, says Beckerman.
"That's because our body is sharp and has built-in mechanisms to keep pH levels in check."
Moreover, alkaline diet proponents say that acidic foods leave behind an "acid ash" in the body, which may promote diseases like osteoporosis. Since then, several studies have shown that this assumption is not true.
The alkaline diet makes dangerous claims about cancer
In 2013, Victoria Beckham tweeted a picture of an alkaline cookbook, setting off a widespread diet trend that ended up influencing scores of celebrities including Kate Hudson, Gweneth Paltrow, and Tom Brady.
The founder of the alkaline diet, Robert Young, made the false claim that the diet aids in cancer treatment. As a result, some cancer patients have turned to the alkaline diet for treatment and found no relief.
In some cases, a strict alkaline diet only caused muscle loss and back pain. Young was later sued and arrested for practicing medicine without a license.
Moreover, the American Institute for Cancer Research also rejects claims that eating acidic foods can lower the body's pH and promote cancer.
Just about the only health condition that an alkaline diet might help is kidney stones. Throughout the 20th century, researchers conducted numerous studies on pH levels in food and their effect on the kidneys. They discovered that eating more alkaline foods can help prevent kidney stones.
The alkaline diet can lead to nutritional deficiencies
Any time you cut food groups out of your diet, you need to be cautious, Beckerman says. "It could be setting you up for nutritional deficiencies if you don't prioritize your food choices."
For example, the alkaline diet cuts out some healthy food options such as eggs and fish while encouraging followers to adhere to strict diet rules. Without careful planning, an alkaline diet can cause muscle loss from a lack of protein and improper nutrition overall.
However, there is anecdotal evidence that the diet has helped people lose weight, stay healthy, and feel better. But this has nothing to do with consuming alkaline foods and everything to do with switching to the plant-based and whole-food options that the diet promotes.
Insider's takeaway
The alkaline diet won't change your body's pH level and could lead to nutritional deficiencies. If healthy, plant-based eating is your goal, there are other diets out there - like the Mediterranean diet or vegetarianism - with the science to back their health benefits.