What Is the Alkaline Diet?

Alkaline diet

Verywell / Debbie Burkhoff

At Verywell, we believe there is no one-size-fits-all approach to a healthy lifestyle. Successful eating plans need to be individualized and take the whole person into consideration. Prior to starting a new diet plan, consult with your health care provider or a registered dietitian, especially if you have an underlying health condition.

The alkaline diet is an eating plan that emphasizes fresh vegetables and fruits with the aim of maintaining an optimal pH level in the body. It's based on the premise that the food we eat alters the body's pH to be either acidic or alkaline.

Followers of an alkaline diet believe eating a diet rich in alkaline-forming foods have unique health benefits, while a diet high in acid-producing foods disrupts the blood's normal pH level. This, in turn, triggers the loss of essential minerals (such as calcium) as the body attempts to restore equilibrium. This imbalance is said to increase susceptibility to illness.

The concept of alkaline and acidic foods was developed during the mid-1800s as the dietary ash hypothesis. It proposed that foods, once metabolized, leave an acid or alkaline "ash" in the body.

According to proponents of the alkaline diet, the metabolic waste—or ash—left from the burning of foods directly affect the acidity or alkalinity of the body. Choosing more alkaline foods, in theory, should alkalize your body and improve health.

The alkaline diet has been used in medical settings to prevent kidney stones and urinary tract infections. However, there is not a lot of science to support many of the purported health benefits of this eating plan.

The 2020 U.S. News and World Report Best Diets ranks the alkaline diet number 28 in Best Diets Overall and gives it an overall score of 2.5/5. Its ranking is based on questionable research, the many rules that make it difficult to follow, and its ineffectiveness for weight loss.

What Experts Say

"There’s little to no evidence supporting the premise of the alkaline diet. Our bodies do a good enough job on their own keeping our pH in check. There are a lot of rules and many foods that are 'hands-off' are actually healthy, like eggs and whole grains."

—Kelly Plowe, MS, RD

What Can You Eat?

To follow the alkaline diet, simply focus on eating lots of alkaline foods and fewer acidic foods. Food groups can either be alkaline, neutral, or acidic. 

  • Alkaline: Fruits, nuts, legumes, and vegetables
  • Neutral: Natural fats, starches, and sugars
  • Acidic: Meat, poultry, fish, dairy, eggs, grains, and alcohol

Acid levels are measured by pH, a scale of 0 to 14 where the lower numbers represent more acidic compounds, higher numbers are more alkaline (or basic), and 7 is neutral.

What You Need to Know

The alkaline diet does not restrict foods to certain times of the day or require periods of fasting. The idea behind the alkaline diet is to eat more alkaline foods and fewer acidic foods. Rather than viewing the food lists as "foods to eat" and "foods to avoid" lists, think of the acid and base-forming foods on a continuum and strive for a balanced diet.

In addition, when following the alkaline diet, it is helpful to monitor your urinary pH to know how nutritional changes affect your body. You can buy urine pH strips online or at your local health-food store. It is recommended that you use your first urine of the day. A number between 6.5 and 7.5 is ideal. 

What to Eat
  • Fruits

  • Vegetables

  • Coffee

  • Red and white wine

  • Lemon and lime juice

What Not to Eat
  • Meat

  • Poultry

  • Fish

  • Dairy

  • Eggs

  • Grains

  • Legumes

Following an alkaline diet isn’t complicated. The goal is simply to eat more alkaline and less acidic foods. Here are some tips to get started: 

  • Eat more fruits and vegetables.
  • Drink less soda or eliminate it altogether. 
  • Aim to drink 64 ounces of mineral water a day. 
  • Add fresh lemon or lime to water. Even though citrus fruits are acidic, they have an alkalizing effect within the body. 
  • Limit animal protein to one serving a day. 
  • Replace refined carbohydrates with vegetables. For example, choose spiralized zucchini or carrots instead of spaghetti or finely chopped cauliflower instead of white rice.
  • Drink alkaline broth. Alkaline broth is an easy-to-make vegetable broth that's packed with vitamins and minerals including potassium.

On the alkaline diet, it is suggested to monitor the pH of your urine to ensure it is alkaline (over 7) and not acidic (below 7).

Pros and Cons

Pros
  • Can be satisfying and filling

  • Plenty of fresh healthy produce

Cons
  • Lots of rules to remember

  • Limited research

The alkaline diet promotes an increased intake of fruits and vegetables and avoids heavily processed foods that are high in sodium and saturated fat. That's beneficial because the typical Western diet is low in fruits and vegetables and has much more sodium and fat than is necessary.

Still, the alkaline diet has its drawbacks. Review the pros and cons to help inform your decision about whether this is the right diet plan for you.

Pros

A diet rich in fruits and vegetables is also very filling, which makes it easier to stick with.

While there is little evidence that an alkaline diet can render the benefits claimed by its supporters (especially that the diet can materially affect blood pH for the purpose of treating diseases), there is no doubt that eating fewer processed foods is a good thing.

It's important to note, however, that pH levels in the body vary greatly. The stomach, for example, is filled with hydrochloric acid with a pH of 2 to 3.5, which is necessary to break up food during digestion. 

Cons

There is no scientific evidence to support the premise that following an alkaline diet can improve health or that eating certain foods can change the pH of the body.

As far as fad diets go, this one doesn't seem to be too risky, but it does restrict some nutritious foods such as milk and dairy products, which are excellent sources of dietary protein and calcium.

That's unfortunate (and unfounded) because research studies indicate consuming these foods doesn't have an acidifying effect on the body, nor does it interfere with calcium metabolism. Eating meat doesn't change the pH of your body either.


Blood is slightly alkaline with a pH between 7.36 and 7.44. If it falls outside those ranges, it can be fatal. One example is metabolic ketoacidosis, which is caused by diabetes, starvation, or alcohol intake, and has nothing to do with diet. 

What Is Potential Renal Acid Load?

Scientists have used various techniques to analyze foods and determine the acid or base load of each food on the body. On the alkaline diet, foods are measured by their potential renal acid load. A negative number is more alkaline and a positive number is more acidic.

Researchers Thomas Remer and Friedrich Manz developed a measure called the potential renal acid load (PRAL). On the PRAL scale, 0 is neutral, while negative numbers are basic and positive numbers are acidic.

The following PRAL tables are adapted from the study by Remer and Manz and include PRAL levels for many alkaline and acidic foods.

Alkaline Foods
FOOD Potential Renal Acid Load (PRAL) mEq/100g
Fruit  
Apples -2.2
Apricots -4.8
Black currants -6.5
Lemon juice -2.5
Oranges -2.7
Peaches -2.4
Pears -2.9
Raisins -2.1
Strawberries -2.2
Watermelon -1.9
   
Vegetables  
Asparagus -0.4
Broccoli -1.2
Carrots -4.9
Celery -5.2
Cucumber -0.8
Green beans -3.1
Lettuce -2.5
Potatoes -4.0
Spinach -14.0
Tomatoes -3.1
   
Beverages  
Coffee -1.4
Red wine -2.4
White wine -1.2
Apple juice, unsweetened -2.2
Orange juice, unsweetened -2.9
Lemon juice, unsweetened -2.5
   
Condiments and Sweets  
Honey -0.3


Vegetables
and fruits, by comparison, have negative PRAL numbers. Spinach (-14.0 PRAL), for example, is more base-forming than watermelon (-1.9 PRAL).

Acidic Foods
FOOD Potential Renal Acid Load mEq/100g
Meat  
Beef 7.8
Chicken 8.7
Pork 7.9
Salami 11.6
Turkey 9.9
   
Fish and Seafood  
Cod 7.1
Trout 10.8
   
Milk, Dairy, and Eggs  
Cheddar cheese, reduced fat 26.4
Cottage cheese, plain 8.7
Eggs 8.2
Egg white 1.1
Ice cream, vanilla 0.6
Milk, whole 0.7
Yogurt, plain 1.5
   
Beans and Legumes  
Lentils 3.5
   
Grain Products  
Bread, whole wheat 1.8
Bread, white 3.7
Rice, brown 12.5
Spaghetti 6.5
White flour 8.2
   
Nuts  
Peanuts 8.3
Walnuts 6.8

Foods such as cheese, meat, fish, shellfish, and grains produce acid after being consumed and have higher PRAL numbers. Cheddar cheese (26.4 PRAL), for example, is more acid-forming than egg whites (1.1 PRAL).

Is the Alkaline Diet a Healthy Choice for You?

The alkaline diet emphasizes eating fresh whole foods, with a variety of fruits and vegetables and limited processed food. It allows for small amounts of animal protein and dairy while reducing refined grains, providing a wide array of nutrients.

The U.S. Department of Agriculture (USDA) dietary guidelines include calorie recommendations and tips for a healthy, balanced diet. The following nutrient-dense foods are recommended by the USDA:

Adopting a plant-based diet rich in fruits and vegetables may help you achieve overall wellness and protect against certain diseases. However, the alkaline diet has plenty of healthy foods on the acid-forming list (grains, beans, nuts), while the base list includes coffee and wine, which should only be consumed in moderation.

The USDA recommends consuming roughly 1,500 calories per day for weight loss, but this number varies based on age, sex, weight, and activity level. Use this calculator to determine your personal calorie needs.

The alkaline diet allows all of the foods recommended by the USDA to be consumed, although it restricts certain amounts of grains, legumes, animal protein, and dairy, and therefore, is not always recommended as a balanced diet.

Health Benefits

So far, there's little scientific support for claims that the alkaline diet can promote weight loss and fight disease. However, some research suggests that the diet may offer certain health benefits.

Preserves Muscle Mass

Following an alkaline diet may help preserve muscle mass as you age—an important factor in preventing falls and fractures. A three-year clinical trial of 384 men and women (ages 65 and up) published in the 2008 American Journal of Clinical Nutrition determined that a high intake of potassium-rich foods, such as the fruits and vegetables recommended as the foundation of the alkaline diet, may help older adults maintain muscle mass as they get older.

In a 2013 study published in Osteoporosis International, researchers analyzed data on 2,689 women ages 18 to 79 and found a "small but significant" association between adherence to the alkaline diet and maintenance of muscle mass.

Prevents Diabetes

There's also some evidence that an alkaline diet may protect against diabetes. In a study published in the German journal Diabetologia in 2014, 66,485 women were followed for 14 years. During that time, 1,372 new cases of diabetes had occurred. In their analysis of the participants' food intake, researchers determined that those with the most acid-forming diets had a significantly greater risk of developing diabetes.

The study's authors suggest that a high intake of acid-forming foods may be linked to insulin resistance, an issue closely linked to diabetes.

Protect Against Kidney Disease

A higher dietary acid load is said to increase metabolic acidosis and increase the risk of kidney disease progression. In a 2015 study, researchers followed 15,055 people without kidney disease over 21 years (who were part of the Atherosclerosis Risk in Communities study) and found that after adjusting for other factors (like risk factors, caloric intake, and demographics), a higher dietary acid load was associated with a higher risk of developing chronic kidney disease.

Of the individual dietary components, a higher magnesium intake and vegetable sources of protein had the strongest protective association with chronic kidney disease.

Prevent Cardiovascular Disease

A high acid load diet may be associated with higher mortality rates, although the research is conflicting. A 2016 study found that people with the highest PRAL had a significant increase in atherosclerotic cardiovascular disease and tended to belong to the high-risk group compared with those with the lowest PRAL scores.

However, a second study found both highly acidic and highly alkaline diets have high mortality rates, while those with a more neutral diet had greater longevity.

In a study published in the Journal of Nutrition in 2016, researchers used data from the Swedish Mammography Cohort and the Cohort and Swedish Men, which included 36,740 women and 44,957 men at the start of a 15 year follow-up period.

In both men and women, researchers found higher mortality rates in those who consumed either a high dietary or alkaline load diet compared to those who consumed an acid-base balanced diet.

Reduce Fracture Risk

It is believed that a highly acidic diet increases the risk of osteoporosis and fractures in older adults. The theory is the body leeches calcium—an alkaline substance—from bones to balance out the acidity. However, the research does not support this.

In a 2015 study, researchers followed 861 men and women age 70 and found that dietary acid load had no significant associations with bone mineral density or with the diagnosis of osteoporosis.

Health Risks

While there are no common risks associated with the alkaline diet, it's evident that more research is still needed to determine its effectiveness. Additionally, following the alkaline food lists too strictly without considering other factors (like protein or overall caloric intake) can lead to health problems like protein or nutrient deficiency or excessive weight loss.

Additionally, people on medications that affect the body's levels of calcium, potassium, or other minerals should check with their doctor before trying the alkaline diet.

If you have a health condition (such as kidney disease or cancer), be sure to consult your care provider before making any change to your diet.

Similar Diets

The alkaline diet shares some features with many healthy eating plans. Similar diets include:

  • Plant-based diet: A vegetarian diet, this plan includes lots of vegetables and fruits, along with grains and legumes, while avoiding processed foods. Some versions allow limited meat and dairy products.
  • Mediterranean diet: This diet emphasizes plant-based eating but encourages the consumption of fish and allows for small amounts of chicken, dairy products, eggs, and red meat.
  • Flexitarian diet: Also known as a "flexible vegetarian" diet, this eating plan emphasizes plant-based foods but allows for occasional allowances of foods that are not typically considered vegetarian.
  • The Tom Brady Diet: This diet created by the Superbowl champion excludes gluten, dairy, corn, soy, MSG, coffee, alcohol, GMOs, sugar, trans fats, overly processed foods, and more.

A Word From Verywell

As long as you're healthy, your body does a good job of regulating the various pH levels. While some health conditions such as kidney disease and diabetes may alter pH regulation, there's no scientific evidence to support the concept that certain foods will make your whole body more acidic.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, and budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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Article Sources
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