Are the Alkaline Diet Benefits Legit?

And, uh, do you really need to test the pH of your pee to follow this celeb-loved diet?

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For better or worse, when celebrities praise a diet or specific way of eating, people listen. That's what happened when A-listers like Jennifer Aniston, Victoria Beckham, and Gwyneth Paltrow promoted cookbooks, programs, and even bottled water inspired by the alkaline diet in the early 2010s.

And for some reason, this eating style has true staying power. "We've seen dozens of diet trends rise and fall, but the alkaline diet remains a topic of conversation for those looking to get healthy, change their body composition, or use it as a hope to cure or delay disease," says Claire Fudge, BSc RD, an advisor to Caliber Fitness.

But what does the diet entail, and are the alkaline diet benefits real? Nutrition pros weigh in, ahead.

What is the alkaline diet?

"The alkaline diet is a whole food, primarily vegan, typically gluten-free diet with a primary focus on plant foods," says Lauren O'Connor, MS, RDN, author of The Healthy Alkaline Diet Guide.

The diet emphasizes fruits and vegetables, which are considered "alkaline-forming." But what does that mean exactly?

"The alkaline diet originates from the acid-ash hypothesis, which claims that our typical diet causes us to create excess acid, which lowers our blood pH," explains Aja Gyimah, RD, MHSc, an expert at kuudose. (That would mean our blood is more acidic than it should be.)

You might remember pH from high school, Fudge says. It's measured on a scale from 0 to 14. 7 is neutral, below 7 is acidic, and above 7 is a base.

The acid-ash hypothesis says that excess acid in our blood must be neutralized, otherwise, it might cause issues such as osteoporosis, cancer, diabetes, cardiovascular disease, and more, according to Gyimah. So the idea of the alkaline diet is to prevent long term health problems by eating foods that do not produce acid in the body.

In practice, that doesn't look so different from your typical healthy diet. "The alkaline diet promotes eating fruits and vegetables and limiting saturated fats, trans fats, refined sugars, and high intakes of red meat," O'Connor says.

The difference, though, is that the diet bases its guidelines on the type of residue left behind when the body metabolizes a given food: either acid or alkaline.

  • Foods considered acid-forming include: beef, pork, poultry, dairy, highly-processed foods, and alcohol
  • Foods considered alkaline-forming include: fruits, vegetables, nuts, and legumes
  • Foods that are considered neutral include: natural fats, starches, and sugars

Following the diet is simple: Eat alkaline and neutral foods, and avoid acid-forming foods. People will often test their urine or saliva using pH strips to check if they are in an "alkaline" state.

Alkaline diet drawbacks: The downsides

So, there are a few big problems with the alkaline diet. Most importantly...

Science doesn’t support it.

Though minimizing processed foods and eating more plants isn't a bad thing, the reasoning behind the alkaline diet's food categories doesn't hold up.

"To date, there is no scientific research that has shown an alkaline diet to alter the body's pH," says Maya Feller, MS, RD, CDN of Brooklyn-based Maya Feller Nutrition. "The alkaline diet has been shown to have some impact on the pH of urine, but not the blood." That's because the kidneys, lungs, digestive system, and liver ensure a healthy individual maintains a blood pH of 7.35 to 7.45, Feller says. "Deviations outside of that narrow pH range can be fatal, but are very rare unless the body is seriously compromised with a medical or congenital condition."

In other words — the foods we eat don't impact blood pH in a meaningful way, so even if your urine is testing "alkaline," it doesn't mean you're getting health benefits from the diet.

It’s super restrictive.

In general, nutrition pros are not big fans of diets that cut out entire food groups without the presence of a food intolerance or sensitivity. A one-size-fits-all approach, like the alkaline diet, is unlikely to be successful long-term. "This diet is quite restrictive with regard to the consumption of meat, dairy, and whole grains," Feller points out. Though it's definitely possible to have a healthy eating pattern that excludes those foods, the diet's flawed hypothesis isn't a good reason to nix them.

It requires careful planning.

Because many protein sources are excluded from the alkaline diet, following this eating pattern and meeting your protein needs can be tricky. You'll need to consider alternative sources for complete proteins, or essential amino acids, Feller says. "Essential amino acids are the building blocks of protein that cannot be synthesized in the body, and play a number of critical roles in the body."

Specialized alkaline products are pricey.

"Supplement companies have popped up promoting products and foods that claim to have alkalinization capabilities," Gyimah points out. "However, considering there's little research to support the acid-ash hypothesis, consuming these products likely won't provide the benefits consumers are looking for, and may be quite expensive."

Alkaline Diet benefits: The upsides

It emphasizes whole foods.

Due to the lack of evidence for the alkaline diet, Gyimah wouldn't recommend it to her clients. "However, the alkaline diet encourages people to eat plenty of fruits, vegetables, and legumes and to consume less processed foods and alcohol, which aligns pretty well with healthy eating guidelines," she says. "A diet high in fruits, vegetables, and legumes is beneficial to our health even though it may not affect our pH."

It may help with some health issues — but not because of pH.

"Research continues to be quite clear that plant-based diets have a positive effect on blood pressure, bone health, and acid reflux management due to their nutrient content — not their pH," O'Connor says. "For example, there is significant, substantial scientific evidence that potassium (a mineral highly present in many of your fruits and vegetables) has a role in both sodium-balance and vasodilation — thus ideal for blood pressure control."

It might help with weight loss.

Another side effect of focusing on fruits and vegetables and eliminating processed foods: "It would certainly decrease the likelihood of overconsuming calories, and it would be likely to increase the intake of essential micronutrients and fiber," Fudge says. While reducing calorie intake is required for weight loss, the addition of fiber, which is highly satiating, can also help.

The Bottom Line

"Diets such as the alkaline diet make healthy eating harder than it needs to be," Gyimah says. "I'm a big fan of easy, healthy eating and you can do this by eating more plants and whole grains." In other words: Eating healthy doesn't have to be this complicated — or require testing your urine.

Updated by Julia Malacoff
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