A nutrient is a substance the body needs but cannot make in sufficient amounts, so it has to come from food. There are six classes, and each one is defined by the job it does — supplying energy, building structure, or regulating a process. Tap a class to see its job, then use the sliders to watch where a day's energy actually comes from.
The three jobs
Energy yield tap a class
Energy math: grams in, kilocalories out
Only three nutrient classes release usable energy, and they do not release it equally. Set a day's grams and watch the two bars disagree.
Carb0
Protein0
Fat0
Alcohol0
Total energy0 kcal
4 · 4 · 9 · 7. Carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g. Alcohol is not a nutrient — it yields energy but supplies nothing the body requires, so it is shown separately.
This is arithmetic, not a verdict. It describes where energy came from, not whether a day was well or badly eaten. Energy needs differ enormously between people, and this tool does not estimate anyone's.
Six classes of nutrientstap one to begin
Energy-yielding vs notCarbohydrate, protein, and fat are the only classes that release usable energy. Vitamins, minerals, and water release none — yet without them the energy in the other three cannot be unlocked, transported, or used. "Zero calories" is not the same as "does nothing."