The alkaline diet is based on the idea that acidic foods can change the acid-base balance of your body.
Proponents of the alkaline diet say that the pH levels of metabolic waste, a byproduct of food consumption, can affect your body’s acidity. According to alkaline diet advocates, eating an acidic diet increases your risk of health issues like osteoporosis, cancer, heart disease, and diabetes.
Because the keto diet is high in animal protein and other “acid-forming” foods, some people claim it results in health problems that can be prevented by eating a more alkaline diet.
In this article, you’ll learn the differences between keto and alkaline diets, how your body maintains a healthy pH balance, and what the science really says about alkalinity and health.
The ketogenic diet is a high-fat, low-carb diet with adequate protein intake. The keto diet is popular because many people find that it helps them burn fat, maintain a healthy weight, improve mood and cognition, boost energy levels, and prevent disease.
The most striking feature of the keto diet is its focus on consuming healthy fats over carbohydrates.
In contrast to positive findings, many studies find no relationship whatsoever between dietary acid load and disease. Again, this is because even if you eat an “acidic” or “alkaline” diet, your body can regulate your pH effectively to prevent problems–regardless of your diet.
The keto diet causes your body to enter ketosis, which is a state where your body and brain rely on fat-burning and ketone production to meet your energy needs[*].
The alkaline diet, also called the alkaline ash diet, is based on the premise that eating acidic foods can alter the pH balance (acid-base balance) of your body.
When you eat food, your metabolism breaks food down into metabolic waste through a series of chemical reactions. This metabolic waste, sometimes called “ash,” can be acidic (pH under 7.0), neutral (pH 7.0), or alkaline (pH over 7.0).
According to proponents of the alkaline diet, the pH of your body’s metabolic waste can affect your body’s acidity and increase your risk of health problems including osteoporosis, diabetes, cancer, heart disease, and hypertension.
As a result, they believe that eating alkaline foods improves your health by creating an alkaline state in your body.
Foods that create acidic ash include meat, fish, eggs, dairy, grains, and alcohol. Some examples of foods that create alkaline ash are fruits, nuts, vegetables, and legumes.
Although the food you eat can affect your urine alkalinity, it does not change the pH of your blood or other areas of your body.
So while the underlying idea of acid or alkaline-forming foods contains a kernel of truth, most scientists aren’t convinced that it can affect your health dramatically.
How Does Your Body Regulate pH?
The pH of your body varies greatly, whether you’re talking about your skin, your stomach, or other body parts.
It is usually tightly regulated as opposed to being influenced by your diet. Here are some examples of the pH in different areas of your body[*]:
- Your skin’s natural pH is 4-6.5, which protects against germs
- Your stomach pH is 1.35-3.5, which allows it to break down protein
- Your bile pH is 7.6-8.8, which neutralizes stomach acid and aids in digestion
- The pH of vaginal fluid is 4.7 or less, which prevents microbial overgrowth
- Venous blood has a pH of 7.35
- Arterial blood has a pH of 7.4
Along with respiration, your body regulates the pH of your blood and organs by excreting acids during urination. The pH of your urine can range from 4.6 (acidic) to 8.0 (alkaline)[*].
Some advocates of the alkaline diet recommend monitoring your urine pH with testing strips and eating in a way that ensures it is alkaline rather than acidic.
According to alkaline diet advocates, acid-forming diets high in protein can force your body to “steal” calcium, an alkaline mineral, from your bones. This calcium is said to buffer the acid produced by the foods you eat.
But in reality, your kidneys are responsible for removing acid from your bloodstream and regulating your body’s pH[*].
Your kidneys produce bicarbonate ions to neutralize acidic waste products in your blood, which allows your body to regulate the pH of your blood[*]. Another way your body adjusts your blood pH is during the formation of carbon dioxide, which you exhale as you breathe.
While some of the health claims made by alkaline diet proponents are incorrect, alkaline diets are high in healthy whole foods like fruits and green vegetables.
This is likely the reason why some studies show health benefits from eating more alkaline ash-forming foods.
Conversely, diets like the high-carb Western diet, which is associated with obesity and increased risk of heart disease, diabetes, and cancer, tend to result in more acidic metabolic waste formation[*][*][*][*]. However, that does not prove that acidity is the reason Western diets cause health problems.
A Japanese study of 2,028 employees between the ages of 17 and 70 found an association between high dietary acid load and high blood pressure[*].
In a separate study of 1,732 workers, aged 19-69 years, researchers found that dietary acid load was positively associated with insulin resistance, but not fasting glucose or glycated hemoglobin[*].
A five-year observational study of over 3,000 men found that the men with the lowest urinary pH were more likely to have diabetes[*].
There is some evidence that eating an alkaline-forming diet may reduce your symptoms if you suffer from chronic kidney disease[*]. And if you have kidney stones, eating a low-acid diet may decrease your body’s production of stones[*].
In contrast to positive findings, many studies find no relationship whatsoever between dietary acid load and disease. A study of over 6,000 Polish adults found there was no association between eating acid ash-forming foods and cardiovascular disease[*].
There is zero evidence that alkaline diets or alkaline water can help prevent cancer.
A large systematic review that examined over 8,000 citations and 252 abstracts found a single study examining the relationship between acidity and cancer, which indicated there was no relationship between dietary acid load and bladder cancer[*].
Contrary to the claim that cancer requires an acidic environment to grow, some types of esophageal, stomach, bronchial, cervical, and bowel cancers thrive in an alkaline environment[*].
A meta-analysis of the effects of protein intake and dietary acid load on bone health found that high-protein diets aren’t linked to impaired calcium balance[*]. That means “acidic” diets most likely don’t harm your bones. In fact, the opposite is true: more protein means healthier bones
The authors of a different study concluded that, rather than increasing the risk of bone disease and hip fracture, a diet high in meat protein increases bone mineral density[*]. They concluded that seniors should eat high-protein diets rich in fruits and vegetables to prevent osteoporosis[*].
After performing an analysis of published literature in 2017, researchers found no evidence of athletic performance benefits from reducing dietary acid load[*].
If you’re already on the keto diet, the good news is that you don’t need to worry about health issues from eating protein or other “acid-forming” foods.
Because your body regulates the pH of your blood and organs effectively through your kidneys and respiration, you aren’t going to create acidic conditions by eating keto.
Nor is eating a high-protein diet associated with an increased risk of osteoporosis or other health problems. In older adults, eating a high-protein diet improves health and wellness, as opposed to a low-protein alkaline diet[*].
While a few studies show positive results from eating a more alkaline diet, the odds are high those effects are not due to changes in urinary pH, but rather because alkaline diets are rich in healthy whole foods, like green vegetables.
Eating plenty of veggies boosts your health–it’s a wise move, period. And that’s easy to do on a healthy keto diet.
As long as you eat real, whole foods, and keep processed foods and refined carbs to a minimum, you can look forward to better health and a decreased risk of illness. There’s no need to measure your urinary pH.