What food makes the body more acidic? A guide to PRAL values

November 17, 2025 •

4 min read

According to research published in the British Journal of Nutrition, the potential renal acid load (PRAL) of a diet can influence metabolic balance over time. Understanding what food makes the body more acidic is key for those interested in managing their acid-alkaline balance through dietary choices.

Quick Summary

Certain food groups, including high-protein animal products, processed grains, and sugary drinks, increase the body's acid load during metabolism. The PRAL score measures this effect, indicating which foods are more acid-forming.

Key Points

Protein's Role: Animal proteins like meat, poultry, and fish are primary acid-forming foods due to their high content of sulfur-containing amino acids.
PRAL Score: The Potential Renal Acid Load (PRAL) measures a food's acid-forming effect after metabolism, with a positive score indicating a higher acid load.
Processed Culprits: Highly processed foods, refined sugars, unhealthy fats, and carbonated beverages are significant acid-forming contributors to the diet.
Fruit's Alkalizing Effect: Despite their initial sour taste, most fresh fruits and vegetables are alkaline-forming once metabolized, providing a buffering effect.
Balance is Key: Healthy individuals have robust systems to regulate body pH, but adopting a balanced, plant-rich diet can support overall wellness and reduce metabolic stress.

The Science of Acid-Alkaline Balance and PRAL

While your body's pH is tightly regulated by your kidneys and lungs, the food you consume can influence the acid load, especially in your urine. This metabolic effect is measured by the Potential Renal Acid Load (PRAL) score, an estimate of the acid or alkaline residue a food leaves after digestion. A positive PRAL value indicates a food is acid-forming, while a negative value signifies it is alkaline-forming. While a healthy body can manage this balance, chronically high acid-load diets are a concern for some, particularly those with existing conditions like chronic kidney disease.

High PRAL: Key Acid-Forming Food Groups

Animal Proteins

Animal-based proteins are among the most significant contributors to a high acid load. During metabolism, the sulfur-containing amino acids in protein break down, creating an acidic residue. This includes most meats, poultry, and fish.

Red Meat: Beef, pork, and processed meats are particularly high on the acid-forming scale.
Poultry and Fish: Chicken, turkey, salmon, and other seafood also produce an acidic effect.
Eggs: The high protein content in eggs, especially the yolk, makes them acid-forming.

Dairy Products

Certain dairy items can increase the body's acid load due to their protein and phosphate content. Hard cheeses, in particular, are known to have a positive PRAL score. However, some dairy, like unsweetened milk and yogurt, can be more neutral.

Grains and Cereal Products

Grains are a staple in many diets but are generally acid-forming. This is largely due to their protein content.

Wheat: Products made from refined wheat flour, such as bread and pasta, are common acid-formers.
Rice: White and brown rice contribute to the body's acid load.
Cereals: Processed cereals and granola often have a positive PRAL value.

Processed Foods, Sugars, and Condiments

Highly processed items are often high in sodium, sugar, and unhealthy fats, all of which contribute to an acid-forming metabolic state.

Packaged Snacks and Fast Food: These items are typically loaded with refined ingredients.
Table Sugar and Corn Syrup: Refined sugars create an acidic residue in the body.
High-Sodium Condiments: Products like soy sauce and certain salad dressings can also increase the acid load.

Beverages

Many common drinks can significantly contribute to the body's acidity.

Carbonated Drinks and Sodas: The phosphoric acid in many dark sodas, combined with high sugar content, is highly acid-forming.
Alcohol and Caffeine: Both alcohol and excessive caffeine consumption can increase the body's acid load.

Acidic vs. Alkaline-Forming Foods Comparison


Food Category	Examples (Acid-Forming/High PRAL)	Examples (Alkaline-Forming/Negative PRAL)
Protein	Beef, pork, poultry, fish, eggs, some cheeses	Tofu, tempeh, most beans and lentils, almonds
Grains	Wheat bread, pasta, white rice, packaged cereals	Millet, quinoa, amaranth
Fruits	Citrus fruits, plums, grapes (Note: initially acidic, but often alkalizing post-metabolism)	Bananas, melons, most fresh fruits and berries, raisins, lemons, limes, tomatoes
Vegetables	Canned asparagus, dill pickles	Spinach, kale, broccoli, cucumbers, potatoes, beets, cabbage
Beverages	Soda, coffee, alcohol, sugary drinks	Herbal tea, water, green juice, almond milk

Balancing Your Diet for Better Health

While avoiding all acid-forming foods isn't realistic or necessary, a balanced approach can promote overall wellness. The goal isn't to make your blood pH alkaline, as this is tightly regulated, but rather to support your body's natural buffering systems and reduce the overall acid load from your diet.

Here are some practical steps to achieve a better acid-alkaline balance:

Increase your intake of fruits and vegetables, aiming for a higher ratio of these alkaline-forming foods compared to acid-forming ones, such as meat and grains.
Prioritize lean, high-quality protein sources in moderation, alongside plenty of plant-based foods to buffer the acidic effect.
Swap refined grains for healthier, less acid-forming options like quinoa and millet.
Limit highly processed snacks, fast food, and sugary drinks, replacing them with whole, unprocessed alternatives.
Incorporate more nuts, seeds, and healthy oils like olive oil and avocado oil into your meals.
Choose filtered water and herbal teas over carbonated and caffeinated beverages.

Conclusion

Maintaining a healthy acid-alkaline balance is more about dietary patterns than a single food item. Foods rich in protein and phosphorus, along with processed sugars and beverages, increase the body's metabolic acid load, or PRAL. Conversely, a diet rich in fruits, vegetables, and other plant-based foods helps provide a buffering, or alkaline, effect. Instead of adhering to a restrictive diet, focusing on a balanced intake with an emphasis on nutrient-dense plant foods is a more sustainable and beneficial approach for overall long-term health, as supported by nutritional science.

For more in-depth nutritional information, you can consult reputable sources such as Nutrition.gov.

Frequently Asked Questions

No, despite lemons being acidic in their raw state, they have an alkalizing effect on the body after digestion and metabolism, leading to a negative PRAL score.

No, a healthy body has sophisticated and effective buffer systems involving the kidneys and lungs to keep blood pH within a very tight, healthy range. Diet can, however, affect the pH of your urine.

Most animal proteins are acid-forming due to their amino acid composition. However, many plant-based protein sources, like nuts, seeds, beans, and lentils, are alkaline-forming.

Processed foods are often high in refined sugars, unhealthy fats, and sodium, and low in minerals. The combination of these ingredients and lack of alkaline minerals results in a net acid load after digestion.

While the kidneys are responsible for processing dietary acid load, a chronically high acid-load diet, common in Western countries, can pose health risks. For individuals with existing chronic kidney disease, an acid-forming diet can accelerate the disease's progression.

The most alkalizing foods include most fresh fruits and vegetables. Specific examples include spinach, kale, bananas, melons, raisins, almonds, and quinoa.

No, completely cutting out acid-forming foods is neither necessary nor healthy. Many acid-forming foods, such as whole grains and lean proteins, contain vital nutrients. The key is balance, focusing on increasing your intake of alkaline-forming fruits and vegetables.