What Is the Alkaline Diet? Review, Research, Food List, and More

The alkaline diet, also called the alkaline-ash diet or alkaline-acid diet, was made popular by its celebrity followers. Big names like Victoria Beckham, Kate Hudson, and Tom Brady have said that they’ve tried the diet with positive results.

In 2013, Victoria Beckham tweeted that the alkaline cookbook Honestly Healthy: Eat With Your Body in Mind, the Alkaline Way, written by vegetarian chef Natasha Corrett and nutritionist Vicki Edgson, was her favorite. Since then, the alkaline diet has become much more common.

But celebrity diets don’t necessarily work for everyone or yield long-term results. Not to mention, there’s a lack of research behind the main principles of the alkaline diet — and for some people, the approach may come with health risks.

So, is it healthy or not? This guide will help you decide whether trying the alkaline diet is right for you.

The premise of the alkaline diet is that the foods we eat affect our blood’s pH balance. You may recall from chemistry class that pH is a measure of how acidic or alkaline something is. It ranges from 0 to 14.

• 0 is extremely acidic
• 7 is neutral
• 14 is very alkaline

Proponents of the alkaline diet believe that diets high in certain foods, such as meat and grains, and low in others, such as potassium-rich vegetables and fruits, can cause imbalances in blood pH that lead to a variety of health problems. This is known as the acid-ash hypothesis, which is why the alkaline diet is sometimes known as the acid-ash diet.

It is important to note, however, that this premise is simply a hypothesis, which means it is unproven. There is no research to support these claims, and in fact one review found that “the human body has an amazing ability to maintain a steady pH in the blood,” regardless of diet.

While the pH of food likely does not matter, the alkaline diet does encourage fairly healthy eating patterns, including emphasizing unprocessed and plant-based foods and limiting red meat and refined grains. One study found that following the alkaline diet would increase several micronutrients, such as potassium and magnesium, which could help lower the risk of hypertension and stroke and improve cardiovascular health, bone health, and cognition. For those reasons, U.S. News & World Report ranked the alkaline diet No. 31 in its Best Heart-Healthy Diets and tied for No. 35 in Best Diabetes Diets.

The alkaline or acid-ash diet classifies foods according to how much acid they produce when digested. That amount isn’t necessarily the same as the acidity level of foods in their raw state. Acid-forming foods produce a pH lower than 7, while alkaline foods result in a pH level greater than 7, research has found. Any foods that are around 7 are considered neutral. With that in mind, the diet recommends:

• Avoiding acid-forming foods, such as meat, dairy, fish, eggs, grains, and alcohol
• Consuming plenty of alkaline-forming foods, such as fruits, vegetables, nuts, and legumes
• Limiting neutral foods, such as starches, sugars, and natural fats

Again, there is no research to indicate that the pH of food has any impact on overall health, whereas there is plenty of evidence that shows it simply is not possible to change the body’s pH through diet. In fact, pH levels vary based on the regions of the body; for example, the stomach is highly acidic, and it needs to be to perform its job.

The kidneys and lungs are largely responsible for maintaining a balanced pH within the body, and the various levels are very tightly regulated. Blood pH ranges from 7.2 to 7.45, says Jennifer Fitzgibbon, RDN, a registered oncology dietitian at Stony Brook University Cancer Center in New York. The kidneys also help balance pH levels in urine, according to UC San Diego Health. A urine pH of 4 is considered strongly acidic, while 7 is neutral and 9 is strongly alkaline, notes Michigan Medicine.

A style of eating can’t change your body’s pH. You may notice a difference in your urine pH, which can be measured with a simple dipstick test (also called a urine test strip), but that won’t tell you your overall levels because urine pH doesn’t reflect your body’s pH, according to MedlinePlus. That’s because excess acid might be excreted through the urine in order to balance the body’s pH levels, notes the American Institute for Cancer Research (AICR).

If your body’s pH changes, it’s because of a serious health issue. Urine with a high pH could indicate a urinary tract infection or kidney stones, while a low pH could signify diarrhea, starvation, or diabetic ketoacidosis, per Michigan Medicine.

Followers and authors of the many guides and recipe books about the alkaline diet say it can treat diseases and chronic conditions, including cancer and kidney disease.

From a scientific perspective, these claims aren’t realistic, says Adrienne Youdim, MD, an associate professor of medicine at the UCLA David Geffen School of Medicine in Los Angeles. But, she says, the foods listed as alkaline tend to be healthy, and when you look at eating approaches like the widely studied and beneficial Mediterranean diet, you can reasonably say that the focus on these foods is a healthy approach.

Despite the alkaline diet having been widely studied, there aren’t any definitive studies suggesting that this approach can have an effect on cancer — one of the biggest draws of the diet. Fitzgibbon says that the cancer treatment theory is based on the claim that cancer cells thrive in an acidic environment. And while that is true in a lab setting, it’s nearly impossible to alter cells in a way that creates a less acidic environment the body, she says. Here is what research has found about the alkaline diet and several chronic health conditions:

Bone Health There are claims that the alkaline diet can reduce the risk of osteoporosis. The theory is referred to as the “acid-ash hypothesis of osteoporosis,” which states that eating an acid-rich diet, such as the Western diet, can erode the bones and lead to osteoporosis by increasing calcium in urine and reducing calcium in the body. But the theory doesn't hold up. Past research published in the Journal of Bone and Mineral Metabolism noted that it seems like acid-producing diets plus low calcium intake could lead to bone issues, but if calcium levels are high, eating an acidic diet might even be protective. Another prior review and meta-analysis concluded that there is no evidence that an acidic diet can lead to bone disease, and there is no evidence that it can protect bones either.

Cancer Prevention There was a preliminary study published in 2019 in the International Journal of Cancerthat found alkaline diets may have a protective benefit against hormone receptor negative–breast cancer, but most of the research has been inconclusive. Most results, however, do point to one dietary measure that may reduce breast cancer risk: eating less meat and more fruits and veggies, researchers reported.

The AICR does not support claims about cancer and the alkaline diet, saying that the acidity and alkalinity of foods aren’t important when it comes to human body chemistry. Instead, the AICR says that eating a largely plant-based diet with lots of fruits, vegetables, and whole grains (without worrying about alkalinity) is a healthy approach that can help lower your risk of cancer and chronic diseases. So, the alkaline diet might be a good approach for people fighting cancer, but not for the reasons given by fans of it, according to a study published in 2018 in Oncology.

Chronic Kidney Disease People with chronic kidney disease may also benefit from focusing on alkaline foods, because too much protein is hard on the kidneys. In an article published in 2017 in the Journal of Renal Nutrition, the author argued that by reducing acid load to the kidneys through a low-protein diet with an emphasis on plant proteins, you may be able to slow kidney disease progression and improve kidney function. Research published in 2018 in the Iranian Journal of Kidney Diseases noted that an alkaline diet slows down the rate at which the kidneys’ blood-filtering systems decline.

Heart Health An earlier review published in the Journal of Environmental and Public Health found that eating more alkaline foods, such as fruits and veggies, may help reduce the risk of hypertension and stroke.

Although weight loss is not a primary goal of the alkaline diet, and no research supports it as a primary outcome, any diet that restricts food groups tends to restrict overall calories. Additionally, the alkaline diet’s emphasis on fruit and vegetables over processed foods is an accepted tenet of weight loss and maintenance.

There is some evidence that following an alkaline diet may help preserve muscle mass, and muscle burns more calories, according to Mayo Clinic. A past study found that following a more alkaline diet was positively associated with higher muscle mass indexes in women, likely because fruits and vegetables contain potassium and magnesium, which help maintain muscle.

The diet is organized around the pH levels of individual foods. Some versions are less strict, meaning they may allow grains for their health benefits, despite their slightly acidic pH. But generally, if you try the alkaline diet, you’ll want to follow the food list below, steering clear of the acidic foods, limiting or avoiding the neutral foods, and focusing on the alkaline foods.

Acid-Forming Foods to Avoid

• Meat
• Poultry
• Fish
• Cottage cheese
• Milk
• Cheese (especially Parmesan cheese, reduced-fat cheddar, and hard cheeses)
• Yogurt
• Ice cream
• Eggs (the yolk in particular)
• Grains (brown rice, rolled oats, spaghetti, cornflakes, white rice, rye bread, whole-wheat bread)
• Alcohol
• Soda
• Lentils
• Peanuts and walnuts
• Other packaged, processed food

Neutral Foods to Limit

• Natural fats, such as olive oil and butter
• Starches, including corn, quinoa, oats, white and brown rice, and sweet potatoes
• Sugars

Alkaline-Forming Foods to Eat

• Fruit
• Unsweetened fruit juices
• Nonstarchy vegetables
• Almond milk
• Mineral soda water
• Soy foods
• Almonds
• Coconut oil

There isn’t a specific meal plan or guide — although you can follow recipes online or from alkaline diet cookbooks, or simply use the list of alkaline foods above to create your own dishes.

A more relaxed version of the alkaline diet that doesn’t strictly eliminate healthy nuts and grains can be beneficial for overall health. Fundamentally, a plant-based diet can be good for lowering your risk of many cancers, heart disease, type 2 diabetes, and stroke, notes the American Heart Association. For those with a history of kidney stones or kidney disease, a plant-based diet — but not necessarily an alkaline diet — may help, according to an article published in 2019 in the Clinical Journal of American Society of Nephrology.

For people without preexisting health conditions, the alkaline diet is generally safe, but some people may be left feeling hungry or may not get enough protein for their needs. In addition to restricting many unhealthy foods, some healthy foods are left out as well.

“Some of the acidic foods are quite healthy, like eggs and walnuts,” says Tracy Lockwood Beckerman, RD, owner of the private nutrition practice Tracy Lockwood Nutrition in New York City. Eliminating these foods can cause people to become obsessive and stay away from nutrient-dense foods that we actually need, she adds.

Although the focus is on healthy plant-based foods, the alkaline diet is not designed for weight loss, and there are no guides for portion control or fitness routines, which the Centers for Disease Control and Prevention recommends for disease prevention. Also, if you aren’t sure how to get enough protein using plant sources, you could be left feeling very hungry.

There is no evidence that the acidity or alkalinity of foods has any impact on overall health or weight, relegating the alkaline diet to the realm of pseudoscience. Despite that, the basic tenets of the alkaline diet, which reduce processed foods and meats in favor of plant-based foods, are reasonable. Speak with your healthcare provider before trying the alkaline diet or any other restrictive diet, to make sure you’re not cutting out important nutrients or unintentionally harming your health.

Additional reporting by Rena Goldman.