At a glance:
- The alkaline diet means eating more vegetables, fruit and legumes, and less processed food.
- Your blood pH always stays within the range of 7.35–7.45 — food does not change it, but your food choices affect your overall health.
- A gradual transition works well for beginners: start by adding plant foods, without immediately restricting everything you usually eat.
- Consult a nutrition professional before making major changes, especially if you have any chronic conditions.
The alkaline diet is an approach to eating that favors foods which, in theory, support a more alkaline environment in the body. Although the concept may seem complicated to beginners, the basic principle is simple: more vegetables, fruit and legumes, and less processed food and animal foods. In this article, we explain what the science actually says about the alkaline diet and how to get started safely.
What is the alkaline diet and how does it work?
The alkaline diet classifies foods as acid-forming or alkaline-forming according to their PRAL score (Potential Renal Acid Load) — a measure that estimates how much acid or alkali accumulates as the products of food metabolism are excreted through the kidneys (Remer, 1995). Vegetables, fruit and legumes have low or negative PRAL scores, while meat, cheese and refined grains have high scores.
It is important to understand that human blood maintains a pH of 7.35–7.45 thanks to buffering systems involving the lungs and kidneys — ordinary food does not significantly change this range (Schwalfenberg, 2012). Following an alkaline diet therefore means shifting the balance of your diet toward plant foods, rather than changing your blood pH. For more on how pH affects the body, read pH and healthy eating.
Which foods can you eat on the alkaline diet?
On the alkaline diet, the following foods make up 70–80% of your daily food intake:
- Vegetables: spinach, broccoli, cucumber, celery, kale, parsley
- Fruit: lemons, avocados, berries, melons, bananas
- Legumes: lentils, chickpeas, black beans
- Nuts and seeds: almonds, chia seeds, flaxseeds
- Whole grains: quinoa, oats (in moderation)
You are advised to limit or avoid:
- Red meat and processed meat products
- Refined sugar and white flour
- Carbonated drinks and alcohol
- Large amounts of dairy products
These food choices largely align with the World Health Organization’s (WHO) general recommendations for healthy eating, which emphasize increasing the proportion of fruit, vegetables and whole grains in your diet (WHO: Healthy diet, 2020). For a general beginner’s guide to nutrition, read Healthy eating.
What does the science say about the actual benefits of the alkaline diet?
The scientific evidence has several layers. In a systematic review, Fenton and Huang (2016) found that evidence linking dietary acid load to cancer is weak and does not support any specific benefit of alkaline water or an alkaline diet for cancer prevention (Fenton, 2016). Changing what you eat does not change your blood pH.
However, Schwalfenberg (2012) notes in his review that the high fruit and vegetable intake associated with the alkaline diet is linked to a lower risk of chronic disease and may support bone health and reduce the loss of muscle mass in older age — but this reflects the general benefits of plant foods, rather than a direct effect of changes in pH (Schwalfenberg, 2012).
In summary, the alkaline diet does not work by directly affecting pH, but its emphasis on eating plenty of plant foods is a well-supported principle of healthy eating.
How can you start the alkaline diet safely — 5 steps for beginners?
Step 1 — Assess your current diet
Keep a food diary for 3–5 days. This will help you identify the most acid-forming foods in your diet (often sugary drinks, processed snacks and fast food).
Step 2 — Start by adding foods
Begin by adding one serving of fresh vegetables or fruit to every main meal. Do not cut out meat and dairy products entirely at the outset — an abrupt change can lead to micronutrient deficiencies.
Step 3 — Stay well hydrated
Drink at least 1.5–2 liters of water a day. Reliable evidence does not support the special health claims made for alkaline water; ordinary tap or spring water is perfectly suitable.
Step 4 — Monitor your protein and iron intake
Following an alkaline diet often reduces the amount of protein and iron you get from animal foods. Replace these sources with legumes, quinoa and nuts. Eating them alongside foods rich in vitamin C improves the absorption of iron from plant foods. Your protein needs are higher when you are actively training — for practical advice, read Post-workout nutrition – II.
Step 5 — Consult a professional
If you have kidney disease, diabetes or osteoporosis, or take medication regularly, speak to your doctor or a nutrition advisor before changing your diet.
How does the alkaline diet fit into an athlete’s nutrition?
If you train, the main challenge is getting enough energy and protein while restricting processed food and animal foods. Pay attention to:
- Iron: spinach, lentils and pumpkin seeds are good sources; vitamin C improves absorption
- Vitamin B12: found almost exclusively in animal foods; a fully plant-based diet requires a supplement
- Adequate fat intake: healthy fats (avocado, olive oil, nuts) are essential for hormone production
Getting enough dietary fat is important for supporting testosterone levels — find out more in Nutrition and testosterone.
References
- Remer T, Manz F (1995). Potential renal acid load of foods and its influence on urine pH. J Am Diet Assoc. 95(7):791-797. PMID: 7797810
- Schwalfenberg GK (2012). The alkaline diet: is there evidence that an alkaline pH diet benefits health? J Environ Public Health. 2012:727630. PMID: 23195127
- Fenton TR, Huang T (2016). Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ Open. 6(6):e010438. PMID: 27245789
- WHO (2020). Healthy diet. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/healthy-diet
Frequently asked questions
Does the alkaline diet change blood pH?
No. Your blood maintains a pH of 7.35–7.45 thanks to buffering systems involving the kidneys and lungs. Food does not change blood pH — but it does affect urine pH and your overall nutrient balance.
Are lemons acidic or alkaline?
Although lemons themselves are acidic (pH ~2), they have a negative PRAL score — meaning they leave an alkaline residue after digestion. This is why lemons are classified as ‘alkaline’ foods within the alkaline diet.
How quickly will you see results from the alkaline diet?
Most people notice changes in energy levels and digestion within 2–4 weeks, as more dietary fiber and water support gut health. Weight changes depend on total calorie intake, not how alkaline your food is.
Is the alkaline diet suitable for athletes?
Yes, but athletes need to ensure they get enough protein, iron and vitamin B12, as animal foods are restricted. Legumes, quinoa and nuts are good alternative sources of protein.
Do you need supplements on the alkaline diet?
Supplements are usually not necessary if your regular diet does not exclude animal foods entirely. A fully plant-based diet definitely requires a vitamin B12 supplement. Your need for vitamin D depends on how much sunlight you get, and supplementation is recommended for most people in Estonia during autumn and winter.
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