Data Methodology
This page explains exactly where the numbers on DMSafeHaven come from, how they are calculated, and how conflicts are handled. The core rule: DMSafeHaven never invents nutrition values, GI values, or research claims. Every value on the site traces to a published source or to a formula applied to sourced data.
1. Nutrition Data: USDA FoodData Central
All nutrition values (calories, carbohydrate, fiber, sugars, protein, fat) come from the USDA FoodData Central database (Agricultural Research Service, U.S. Department of Agriculture).
- Values are reported per 100 g of edible portion and scaled to a stated serving size.
- USDA FoodData Central data is released under CC0 / public domain; official USDA guidance states no permission is needed for its use.
- Where a food is a generic item (e.g., “Apple, raw, with skin”), the generic USDA entry is used. Brand-specific packaged foods are a separate data class and are not yet in this database.
- USDA identifiers (FDC IDs) will be attached per food as the database grows, so every record remains traceable to its exact source row.
2. Glycemic Index: Published Tables Only
GI values are published values from:
- International Tables of Glycemic Index and Glycemic Load Values (Atkinson et al., 2008 and 2021 systematic reviews, published in Diabetes Care / The American Journal of Clinical Nutrition).
- University of Sydney GI Database (glycemicindex.com, maintained by the University of Sydney GI Group).
Three practices follow from this:
- Every GI value is reported together with its published range and an evidence level — a single fixed number overstates the science.
- GI values vary with variety, ripeness, preparation and testing conditions; this variability is stated on every food page rather than hidden.
- The University of Sydney database is used as a verification and citation source, not a bulk-download data set (it is © University of Sydney, all rights reserved). We do not republish its database.
3. Glycemic Load: Calculated by DMSafeHaven
GL is a derived value, calculated by DMSafeHaven from sourced inputs using the standard published formula:
GL = GI × available carbohydrate per serving ÷ 100
available carbohydrate = total carbohydrate − fiber
- GI: published value (section 2).
- Carbohydrate and fiber: USDA FoodData Central (section 1).
- Serving size: a stated, typical serving per food (e.g., 1 medium apple, 1 cup cooked rice), shown on every food page.
The three-way responsibility split is deliberate and kept explicit on every page:
| Value | Source | Role |
|---|---|---|
| Nutrition values | USDA FoodData Central | External authoritative data |
| GI | International Tables / Sydney GI Database | External scientific data |
| GL | DMSafeHaven | Derived calculation (formula applied to the two above) |
4. Evidence Levels
Every GI value carries an evidence level:
| Level | Meaning |
|---|---|
| Strong | Consistent across multiple published studies/databases (e.g., white rice, boiled potato) |
| Moderate | Consistent but with real variability (the majority of values) |
| Low | Limited data or high variability (e.g., dates, dark chocolate) |
| Not established | No sufficiently reliable published value identified — we say so rather than guess |
Where no reliable published GI value exists, the page says “Not established” and explains why, instead of displaying a made-up number.
5. Conflict Handling
Different sources occasionally disagree on a GI value. Our rules:
- The typical value plus the full published range is displayed; both sides of a conflict are represented in the range.
- Conflicts are disclosed, not averaged into false precision.
- When published values for a food vary widely (e.g., dates, rice), the food page says so explicitly and lists the drivers (variety, ripeness, brand).
6. What GI/GL Can and Cannot Do
- GI and GL are population averages from small test groups. They describe general tendencies, not any individual’s response.
- A low-GI food can still raise your glucose more than expected — age, medications, insulin sensitivity, meal composition and timing all matter.
- The meter is the authority. DMSafeHaven’s real blood sugar tests exist precisely because averages are not predictions.
7. Review and Updates
- Nutrition data last verified: August 2026, against USDA FoodData Central.
- Each food page carries its own last-verified date.
- Database errors are corrected as they are found; corrections are documented in the page history.
8. Data Classes Covered (and Not Covered)
- Covered today: common generic foods — fruits, vegetables, grains, legumes, dairy, protein, nuts, sweeteners.
- Not yet covered: brand-specific packaged products (these require manufacturer Nutrition Facts data, which is a separate data class with its own sourcing rules).
9. The No-Invented-Data Rule
This is the operating rule for every page on this site:
DMSafeHaven does not invent GI values, GL values, nutrition values, or research results when reliable data is unavailable. When data is missing, the page says it is missing.
If you find a value you believe is wrong, contact us — verifiable corrections are the most valuable feedback we can receive.
DMSafeHaven provides educational information and is not a substitute for individualized medical advice.