Evidence-Based NASEM Sourced Free Guides

Learn About Dietary Reference Intakes

Clear, science-based guides on calories, vitamins, and minerals — written to help you actually use your DRI results.

How to Use a DRI Calculator for Weight Loss

The 500-kcal deficit explained, why your vitamin and mineral needs don't drop when you eat less, and how to lose fat without depletion.

Dietary Reference Intake explained simply — the four values (EAR, RDA, AI, UL) and how your needs change by age, sex, and life stage.

DRI is the umbrella, RDA is one value inside it. Here's what each term means and which number you should actually follow.

Iron, folate, calcium, calories, and protein — exactly how your nutrient needs change each trimester, sourced directly from NASEM data.

Full RDA, AI, and UL values for every vitamin, mineral, and macronutrient — sorted by age, sex, and life stage. Sourced from NASEM.

Exact iron mg needed for men, women, pregnancy, and kids. Iron-rich foods, absorption tips, anemia signs, and supplement guidance — all in one guide.

600 IU for adults, 800 IU after 70, 4,000 IU upper limit. Deficiency signs, D2 vs D3, food and sun sources — your complete vitamin D guide.

More calories, more zinc, far less iron than women — see the full DRI for men by age, with exact calorie, vitamin, and mineral targets in one chart.

Free, instant results — calories, macros, vitamins, and minerals for your profile.

All values and formulas on this site trace back to authoritative, peer-reviewed sources.

National Academies of Sciences, Engineering, and Medicine (NASEM) — Dietary Reference Intake tables, 1997–2019. Primary source for all RDA, AI, UL, and EAR values.
NIH Office of Dietary Supplements — Vitamin and mineral fact sheets, cross-referenced for nutrient data and food sources.
U.S. Department of Agriculture (USDA) — Dietary Guidelines for Americans, 2020–2025. Used for AMDR macronutrient ranges and Physical Activity Level multipliers.
Health Canada — Joint US/Canada DRI publisher. Confirms North American reference values.
Mifflin MD, St Jeor ST, et al. "A new predictive equation for resting energy expenditure in healthy individuals." American Journal of Clinical Nutrition 1990;51(2):241–247. Source of the calorie estimation formula.