Methodology & Sources

BMI standards and formula

BMI is calculated from body weight and height. Height is converted to meters before applying the formula.

BMIbite uses the WHO adult standard by default and also offers a Chinese adult standard option. The thresholds can differ in the higher BMI range, so the selected standard is shown with the result.

BMI is a screening reference and does not directly measure body fat. It may not be appropriate to interpret adult thresholds for children, pregnancy or some athletes.

BMR and TDEE calculation

BMR is estimated with the Mifflin-St Jeor equation using weight in kilograms, height in centimeters and age in years.

TDEE is estimated as BMR multiplied by an activity factor. Factors such as 1.2, 1.375, 1.55, 1.725 and 1.9 represent increasingly frequent or intensive activity patterns.

Weight-loss calorie deficit

The planner converts the requested weight change into a theoretical energy deficit and divides it across the selected timeline.

The 7,700 kcal/kg figure is a simplified model, not a promise. Real weight change is not linear and is affected by water, glycogen, muscle loss, metabolic adaptation, sleep, medication and adherence.

BMIbite blocks overly aggressive timelines and shows safety guidance. Users should seek professional advice before making major diet or exercise changes.

USDA FoodData Central data

Food lookup uses a compact local index prepared from USDA FoodData Central Foundation Foods and SR Legacy Foods. Nutrition values are reference values per 100 grams and are scaled to the amount entered.

Raw and cooked foods can have substantially different nutrition values. BMIbite preserves the USDA source name and labels food state when it can be identified.

Food values can vary by variety, preparation, brand and recipe. Check packaging or a qualified professional when precision matters.