The Study
Renal function trajectories of Japanese adults with diabetic kidney disease on different diet therapies including energy-restricted and low-carbohydrate diets: a retrospective cohort study
This study watched two groups of people with diabetes and kidney problems for four years—one group ate less carbs, the other ate fewer calories. It found their kidney function changed about the same way. But because the groups weren’t randomly chosen, we can’t say one diet caused the result—it might just be that the people in each group were different in other ways.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
This study looked at people with diabetes and early kidney problems who ate either a low-carb diet (more protein) or a low-calorie diet (less protein) for four years.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 561 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The kidney decline was slower than average for Japanese adults with similar conditions, suggesting higher protein intake within this range didn’t make things worse.
- 2People on the low-carb diet ate 1.2 grams of protein per kg of body weight daily, while those on the low-calorie diet ate 1.0 grams.
- 3Both groups had almost the same rate of kidney function decline: −0.26 vs.
- 4−0.17 mL/min/year.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Diabetology International
Year
2025
Authors
Tomomi Shirai, Sakiko Inaba, Miyu Maemura, Maki Saho, Miyu Sato, Mariko Sanada, Yoko Tsukamoto, Gaku Inoue, Taichi Nagahisa, Shinichi Tanaka, Hajime Tanaka, Hideaki Kurata, Takeshi Katsuki, Toshihide Kawai, Satoru Yamada
Related Content
Claims (5)
Eating a high-protein diet does not make chronic kidney disease worsen faster in people with mild to moderate kidney impairment.
In Japanese adults with diabetic kidney disease, a low-carbohydrate diet is associated with a slower decline in kidney function (eGFR) compared to the average decline seen in the general Japanese adult population.
In Japanese adults with advanced diabetic kidney disease, consuming 1.2 grams of protein per kilogram of body weight per day on a low-carbohydrate diet results in the same rate of kidney function decline over four years as consuming 1.0 grams of protein per kilogram per day on an energy-restricted diet.
Among Japanese adults with diabetic kidney disease, eating a low-carbohydrate diet with 70–130 grams of available carbs per day results in higher protein intake (1.2 grams per kilogram of body weight) than an energy-restricted diet (1.0 grams per kilogram), and the rate of kidney function decline over four years is similar between the two diets.
Among Japanese adults with diabetic kidney disease, eating a low-carbohydrate diet with normal protein levels does not lead to a larger reduction in albumin-creatinine ratio over four years compared to eating a diet restricted in total calories, even though protein intake is higher.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.