Nutrition
Energy needs, food labels and the numbers behind eating well.
Nutrition numbers are estimates wearing the clothes of precision. A calculated basal metabolic rate is a population prediction that lands within roughly 10% of measured resting metabolism for most people — which at 2,000 kcal is a 200 kcal spread. Activity multipliers are broad brackets. Food labels are averages with a permitted margin. This hub explains where the common nutrition figures come from, what they can reasonably be used for, and why they work better as a rough orientation than as a target to hit exactly.
Nutrition tools
Calculators and converters for the measurements in this area.
BMI
General Wellness
Calculate body mass index in feet and pounds or metric units, with its real limits explained.
Open calculator
Water Intake
Nutrition
See the US and European reference values for water side by side, rather than one invented number.
Open calculator
Protein Intake
Nutrition
See the protein RDA and the published ranges for older adults and regular training.
Open calculator
Macros
Nutrition
Turn a daily calorie figure into grams of carbohydrate, protein and fat inside the published ranges.
Open calculator
Nutrition guides
Plain-English explanations of what these measurements mean.
NutritionHow Much Protein Do Adults Need? Three Different Answers
The US Recommended Dietary Allowance is 0.8 grams per kilogram a day, but the figure is a minimum for avoiding deficiency, and position statements for older adults and people wh…
8 min read
NutritionHow Much Water Do You Need Each Day? What the Numbers Mean
US and European reference values for daily water intake differ by roughly a liter, they count water from food and every beverage, and thirst is a workable guide for most healthy…
8 min read
NutritionCarbs, Protein and Fat: What the Official Macronutrient Ranges Mean
US reference ranges allow carbohydrate to supply 45 to 65 percent of calories, fat 20 to 35 percent and protein 10 to 35 percent. The ranges are deliberately wide, and a split i…
8 min read
Blood TestsVitamin D and Vitamin B12 Blood Tests: Units, Ranges and Limits
Vitamin D is measured as 25-hydroxyvitamin D and reported in ng/mL or nmol/L, while B12 is judged from a blood level that sometimes needs a second test to interpret. Here is how…
9 min read
General WellnessIdeal Body Weight Formulas: Where Devine, Robinson, Miller and Hamwi Came From
The four ideal body weight equations in common use were written to size drug doses, not to say what weight is healthiest. They disagree by several kilograms at the same height,…
7 min read
General WellnessBMI Categories Around the World: WHO, CDC and the Asian Action Points
The adult BMI categories used by the WHO and the CDC are the same, but the WHO has also suggested additional action points at 23.0 and 27.5 for some Asian populations. Here is h…
7 min read
Women's HealthWhich Health Calculators Do Not Apply During Pregnancy
Pregnancy changes blood volume, kidney filtration, red cell turnover and energy requirements, and most everyday health equations were derived in people who were not pregnant. He…
8 min read
General WellnessWhat Is BMI and What Does It Actually Tell You?
BMI is weight divided by height squared — a population screening tool invented in the 1830s, not a measure of an individual’s health. It cannot distinguish muscle from fat, says…
10 min read
NutritionBMR vs TDEE: Understanding Daily Calorie Needs
BMR is the energy your body uses at complete rest; TDEE adds everything else you do. Both are predicted from equations rather than measured, and the predictions carry a margin o…
8 min read