Evidence check: HbA1c in the context of Abnehmen

HbA1c (glycated hemoglobin) reflects average blood glucose over the past 2–3 months. During weight loss, HbA1c typically decreases because reduced body fat improves insulin sensitivity. Evidence shows that 5–10% weight loss can significantly lower HbA1c, especially in prediabetes or type 2 diabetes. However, HbA1c is not a direct fat-loss marker; it responds slowly to acute dietary changes. Factors like anemia or kidney disease can distort values. For evidence-based weight management, HbA1c is a useful longitudinal marker but not a standalone target. Its evidence grade is 'practice' because it is widely used in clinical guidelines, though randomized trials often include HbA1c as a secondary outcome. Caveat: Rapid weight loss may transiently affect HbA1c due to altered red cell turnover. Overall, HbA1c is a relevant but indirect indicator of metabolic improvement during weight loss.