A 2026 cohort study of 19,040 Japanese adults found that women eating the most acid-forming foods had 61-72% higher diabetes risk over five years compared to those eating the least acidic diets, according to Gram Research analysis. Men showed no clear association. The findings suggest dietary acid load may influence diabetes risk differently in women, though the effect appears specific to Asian populations.
A major study of nearly 20,000 Japanese adults found that eating foods that create acid in the body may increase diabetes risk, but only for women. Researchers tracked participants for five years and discovered that women who ate the most acid-forming foods were 61-72% more likely to develop diabetes compared to those eating the least acidic diets. Interestingly, men showed no clear connection between acidic foods and diabetes risk. The findings suggest that dietary acid load—how acidic or alkaline your diet is overall—might affect blood sugar control differently depending on sex, offering new insights for preventing diabetes in Asian populations.
Key Statistics
A 2026 cohort study of 19,040 Japanese adults found that women consuming the highest dietary acid load had a 61% increased diabetes risk (OR 1.61, 95% CI 1.09-2.37) compared to the lowest acid load group over five years.
Among 19,040 Japanese participants followed for five years, women with the highest net endogenous acid production showed a 72% increased diabetes risk (OR 1.72, 95% CI 1.18-2.52) compared to the lowest group, while men showed no clear association.
The 2026 Japan Collaborative Cohort Study identified 490 new diabetes cases among 19,040 adults, with the association between dietary acid load and diabetes risk appearing only in women (245 cases), not men (245 cases).
The Quick Take
- What they studied: Whether eating foods that create acid in your body increases the risk of developing type 2 diabetes, and whether this effect differs between men and women.
- Who participated: 19,040 Japanese adults (7,037 men and 12,003 women) with no diabetes at the start, followed for five years to see who developed the disease.
- Key finding: Women who ate the most acid-forming foods had a 61-72% higher chance of developing diabetes compared to women eating the least acidic foods. Men showed no clear pattern.
- What it means for you: If you’re a woman, reducing acid-forming foods in your diet might help lower diabetes risk. However, this finding is specific to Japanese populations and needs confirmation in other groups before making major dietary changes.
The Research Details
This was a prospective cohort study, meaning researchers followed the same group of people over time to see what happened. They started with 19,040 Japanese adults who didn’t have diabetes and tracked them for five years. Researchers measured how acidic each person’s diet was using two different methods: PRAL (potential renal acid load) and NEAP (net endogenous acid production). These are fancy ways of calculating whether someone’s diet leans toward acid-forming or alkaline-forming foods based on what they eat.
Participants completed detailed food questionnaires so researchers could estimate their dietary acid load. The researchers then used statistical methods to compare diabetes risk across different levels of dietary acid load, analyzing men and women separately. They adjusted their results for many other factors that could affect diabetes risk, like age, exercise, weight, and overall diet quality.
This research approach is important because it follows real people in their actual lives rather than testing them in a lab. This makes the findings more relevant to everyday health. By studying a large Japanese population, the researchers could see whether findings from Western studies apply to Asian populations, which is crucial since previous research has shown mixed results in East Asia.
This study is fairly reliable because it involved a large number of participants, tracked them over several years, and adjusted for many factors that could influence results. However, the study relied on people remembering what they ate, which can be inaccurate. The researchers also only identified 490 new diabetes cases total, which is a relatively small number for such a large group. The study was published in a respected peer-reviewed journal, which adds credibility.
What the Results Show
During the five-year follow-up period, 490 people developed diabetes—245 men and 245 women. Among women, those eating the most acid-forming foods had significantly higher diabetes risk. Using the PRAL measurement, women in the highest acid-load group had a 61% increased risk compared to the lowest group. Using the NEAP measurement, the risk was even higher at 72%. These increases were statistically significant, meaning they’re unlikely to have happened by chance.
The pattern was different for men. Men who ate high-acid diets showed no clear increase in diabetes risk. This sex difference is important and suggests that women’s bodies may respond differently to dietary acid load than men’s bodies do. The researchers carefully adjusted their analysis for many factors including age, physical activity, body weight, smoking, alcohol use, and overall nutrient intake to make sure the acid load itself was responsible for the difference.
The study found consistent results using both methods of measuring dietary acid load (PRAL and NEAP), which strengthens confidence in the findings. The association between acidic diets and diabetes risk appeared to be independent of other dietary factors, suggesting it’s not just about eating unhealthy foods in general. The researchers also noted that the effect was strongest in women, with no comparable pattern in men, indicating a genuine sex-specific difference rather than a general population effect.
According to Gram Research analysis, these findings align with some Western studies showing that higher dietary acid load increases diabetes risk, particularly in women. However, previous research in East Asian populations has been inconsistent, with some studies showing no clear association. This Japanese study provides stronger evidence that the Western pattern may apply to Asian women as well, though the lack of effect in men differs from some Western findings and suggests population differences may exist.
The study relied on food questionnaires where people report what they ate, which can be inaccurate. The researchers couldn’t directly measure blood acid levels; they estimated them from diet. The study only included Japanese adults, so findings may not apply to other ethnic groups. Only 490 people developed diabetes during follow-up, which is a relatively small number. The study couldn’t prove that acidic foods cause diabetes—only that they’re associated with higher risk. Other unmeasured factors could explain the connection.
The Bottom Line
Women, particularly those of Japanese or East Asian descent, may benefit from reducing acid-forming foods in their diet as a diabetes prevention strategy. Focus on increasing alkaline-forming foods like vegetables and fruits while moderating acid-forming foods like meat and grains. However, this recommendation is based on observational data and should be discussed with a healthcare provider before making major dietary changes. Men don’t show the same pattern, so this recommendation may not apply to them.
This research is most relevant to women, especially those of Japanese or East Asian descent, who are concerned about diabetes prevention. Women with family history of diabetes or other diabetes risk factors should pay particular attention. Men may not need to focus on dietary acid load for diabetes prevention based on this study. Anyone with existing diabetes should consult their doctor before changing their diet.
Diabetes develops gradually over years, so dietary changes would likely take months to years to show measurable effects on blood sugar control or diabetes risk. Most people wouldn’t see dramatic changes in weeks, but consistent dietary improvements over 6-12 months could meaningfully reduce risk.
Frequently Asked Questions
Does eating acidic foods cause diabetes in women?
A 2026 study of 19,040 Japanese women found those eating the most acid-forming foods had 61-72% higher diabetes risk over five years. However, this shows association, not direct causation. Other factors may explain the connection, and findings may not apply to all populations.
What foods are considered acid-forming?
Acid-forming foods include meat, fish, cheese, grains, and processed foods. Alkaline-forming foods include vegetables, fruits, legumes, and nuts. Your overall diet’s acid-base balance depends on the combination of these foods you eat.
Do men need to worry about dietary acid load and diabetes?
The 2026 Japanese study found no clear association between dietary acid load and diabetes risk in men, unlike in women. Men may not need to focus on this factor for diabetes prevention, though other dietary improvements remain important.
How quickly will changing my diet reduce diabetes risk?
Diabetes develops over years, so dietary changes take time to show effects. Most people wouldn’t see measurable improvements in blood sugar in weeks, but consistent changes over 6-12 months could meaningfully reduce risk.
Should I completely avoid acid-forming foods?
No. Acid-forming foods like meat and grains provide important nutrients. The goal is balance—eating more alkaline-forming vegetables and fruits while moderating acid-forming foods, not eliminating them entirely.
Want to Apply This Research?
- Track daily servings of acid-forming foods (meat, grains, cheese) versus alkaline-forming foods (vegetables, fruits, legumes) to monitor your dietary acid load. Set a goal of 2+ servings of vegetables for every 1 serving of meat.
- Replace one meat-based meal per week with a plant-based alternative, or add an extra vegetable serving to each meal to shift your diet toward more alkaline-forming foods.
- Weekly review of your acid-forming vs. alkaline-forming food ratio. Track any changes in energy levels, blood sugar readings (if you monitor them), or weight over 3-month periods to assess impact.
This research describes an association between dietary acid load and diabetes risk in Japanese women but does not prove causation. These findings may not apply to other populations. Anyone concerned about diabetes risk, especially those with family history or existing health conditions, should consult with a healthcare provider before making significant dietary changes. This article is for educational purposes and should not replace professional medical advice. If you have diabetes or prediabetes, work with your doctor or registered dietitian to develop an appropriate dietary plan.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.