Your body already regulates its own acid levels with remarkable precision, keeping blood pH between 7.35 and 7.45 at all times. You can’t dramatically shift that number through diet alone, but what you eat and how you live does influence how hard your body works to maintain that balance. Depending on what you mean by “acid in the body,” the practical steps look different, whether you’re concerned about metabolic acid load, stomach acid, or uric acid buildup.
How Your Body Controls Acid Levels
Your blood’s hydrogen ion concentration is one of the most tightly regulated variables in human physiology. Three systems work together to keep it stable: your lungs, your kidneys, and chemical buffers in your blood.
Your lungs handle the fastest adjustments. Carbon dioxide is mildly acidic, and every cell in your body constantly produces it as a metabolic byproduct. When CO2 builds up in your blood, your brain signals your lungs to breathe faster and deeper, exhaling more of it and pulling blood pH back up. This happens minute by minute, all day long.
Your kidneys work more slowly but with greater precision. They filter excess acids (or bases) out of the blood and excrete them in urine. This process takes hours to days rather than seconds, but it handles the acids your lungs can’t touch, particularly those generated by the food you eat. Your kidneys need adequate water to do this job well. A standard diet produces roughly 650 milliosmoles of waste solutes daily, and your kidneys require at least 2 liters of urine output to clear a normal load. That translates to drinking roughly 2.5 to 3.5 liters of fluid per day, depending on how much you lose through sweat and breathing.
The third system, chemical buffers in your blood (primarily bicarbonate), acts as a shock absorber, neutralizing sudden shifts before the lungs and kidneys can respond.
What Diet-Induced Acidosis Actually Means
Here’s the key distinction most “alkaline diet” advice glosses over: food does not meaningfully change your blood pH. Your regulatory systems prevent that. However, a diet high in acid-producing foods does create what researchers call “diet-induced acidosis,” a subtle, ongoing push toward the lower end of the normal pH range. Your blood stays within bounds, but your kidneys and buffers work harder to keep it there. Over years, that extra workload may contribute to bone mineral loss, muscle wasting, and kidney strain.
The acid load of food is measured by something called the Potential Renal Acid Load, or PRAL, which estimates how much acid your kidneys need to handle after you digest a given food. Positive values mean the food adds to your acid burden. Negative values mean it helps offset it.
- High acid load: Hard cheeses (23.6 per 100g), meat and meat products (8.0), fish (7.9), flour (7.0), pasta (6.7), bread (3.5)
- Low or alkaline load: Vegetables (-2.8), milk and non-cheese dairy (-2.8)
The pattern is straightforward: animal proteins and refined grains push acid levels up, while fruits and vegetables push them down. You don’t need to eliminate meat or bread. You just want a reasonable balance, with plenty of produce on the plate alongside protein and grains.
Practical Steps to Lower Your Acid Load
The most effective dietary shift is simply eating more vegetables, fruits, and legumes relative to meat and processed grains. This doesn’t require a radical overhaul. Adding a large serving of vegetables to every meal and choosing whole grains over refined flour products makes a measurable difference in how much acid your kidneys need to process.
Staying well hydrated is equally important. Your kidneys can only excrete acids efficiently when they have enough water to work with. Insufficient hydration raises levels of a hormone called vasopressin, which concentrates urine and slows waste clearance. Over time, chronic low water intake can strain kidney function. For most adults, aiming for 2.5 to 3 liters of total fluid daily (from all beverages and water-rich foods) supports optimal acid excretion.
Limiting alcohol, particularly beer, reduces acid load and also lowers uric acid, a specific type of acid that causes gout when it builds up in joints. Cutting back on sugary foods and drinks sweetened with high-fructose corn syrup helps for the same reason: fructose metabolism generates uric acid as a byproduct.
If You’re Concerned About Uric Acid Specifically
Uric acid is a distinct problem from general metabolic acid load. It forms when your body breaks down purines, compounds found in high concentrations in organ meats (liver, kidney, sweetbreads), red meat, and certain seafood like anchovies, sardines, shellfish, and codfish. If uric acid levels climb too high, crystals can form in your joints, causing gout.
The dietary strategy is specific: limit organ meats entirely, reduce portion sizes of red meat, cut back on high-purine seafood, and avoid beer and distilled liquors. On the other side, vitamin C (around 500 milligrams daily) may help lower uric acid levels, and coffee consumption is associated with reduced gout risk, though the mechanism isn’t fully understood. Keeping sugar intake low matters here too, since all forms of excess sugar, not just fructose, appear to increase gout risk.
If You’re Dealing With Stomach Acid
Some people searching for ways to “reduce acid” are really experiencing acid reflux, where stomach acid backs up into the esophagus. This is a mechanical problem more than a dietary one, though what you eat plays a role.
Keeping coffee, tea, and soda to no more than two cups daily is linked with lower reflux risk. A diet relatively higher in fruits, vegetables, whole grains, legumes, poultry, and fish also helps. Beyond food choices, elevating the head of your bed (not just using extra pillows, but raising the bed frame or using a wedge) reduces nighttime reflux by letting gravity keep acid in your stomach. Eating your last meal at least two to three hours before lying down gives your stomach time to empty.
When Acid Imbalance Becomes a Medical Problem
True metabolic acidosis, where your body’s compensatory systems can no longer keep blood pH in the normal range, is a serious medical condition. It occurs in severe kidney disease, uncontrolled diabetes, shock, and other acute situations. Symptoms include rapid, unusually deep breathing (your body’s attempt to blow off CO2), confusion, and lethargy. This isn’t something caused by eating too much meat or not enough kale. It requires medical treatment, typically involving intravenous bicarbonate guided by blood gas monitoring.
Chronic, mild metabolic acidosis can exist as an ongoing condition, often driven by kidney disease that reduces your body’s ability to excrete acids. In these cases, most symptoms come from the underlying disease rather than the acid shift itself. If you have known kidney problems, your doctor may monitor your bicarbonate levels and recommend dietary adjustments or supplements to ease the acid burden on your remaining kidney function.
For most healthy people, the goal isn’t to treat acidosis. It’s to stop making your body work overtime to maintain balance. More plants on your plate, enough water, less processed sugar, and moderate alcohol intake handle the bulk of it.