Micronutrient

Macros decide your weight. Micronutrients decide a lot of how you feel while it changes. They are invisible in a calorie count, which is exactly why a log that tracks only energy can be technically perfect and still leave someone tired.

The ones that go short most often

Iron, particularly in menstruating women and in people eating little or no meat; plant iron is absorbed less well, though vitamin C at the same meal helps. Vitamin B12, which occurs naturally only in animal foods and fortified products, so long-term vegetarians and vegans need a reliable source. Vitamin D, widely low wherever people spend most of the day indoors. Calcium, in diets without dairy. Iodine, where iodised salt is not used.

Why a deficit makes it harder

Eating less food means eating fewer micronutrients unless the quality of that food goes up. A 1,600 kcal diet built from vegetables, dal, curd, fruit and eggs covers far more than a 1,600 kcal diet built from biscuits and chai, even though both log identically.

The practical approach

Do not track them daily; almost nobody sustains that. Instead, build a plate with a protein source, a vegetable and a whole grain most of the time, and check the specific ones your diet pattern is known to miss.