Total Carbs Vs. Net Carbs: Medical Evidence on Blood Sugar and Ketosis Impact
By Maya Lin-Takahashi
Not all non-digestible carbohydrates are created equal. The standard packaging formula treats all polyols and fibers as zero-impact subtractions, but clinical glycemic testing paints a much more nuanced picture:
| Carbohydrate Source | Glycemic Index (GI) | Systemic Absorption | Clinical Deduction Rule |
|---|---|---|---|
| Erythritol | 0, 1 | Excreted via urine (~90%) | Deduct 100% of grams |
| Maltitol (Syrup/Powder) | 35, 52 | Partially metabolized (50, 60%) | Deduct only 50% of grams |
| Xylitol / Sorbitol | 9, 13 | Fermented in colon (~50%) | Deduct 50% of grams |
| Natural Insoluble Fiber | 0 | Zero absorption | Deduct 100% of grams |
| Processed Soluble Fiber (IMOs) | 25, 35 | Partially breaks down into glucose | Deduct maximum 50% of grams |
The maltitol deduction is particularly hazardous. Because maltitol syrup registers a glycemic index of up to 52, consuming a "sugar-free" chocolate bar sweetened with 20 grams of maltitol can mimic the glucose impact of eating standard refined table sugar. Subtracting those 20 grams entirely from total carbohydrates guarantees inaccurate insulin dosing for someone managing insulin-dependent diabetes.
Maya is a hardware enthusiast who tests and reviews smart home devices, smartphones, wearables, and audio gear. She focuses on practical consumer value and build quality.
