- Log what you eat most days, roughly right rather than perfectly right.
- Always log the protein and the carbohydrate source of a meal, and its time.
- Log the exceptions to the meal plan rather than re-entering the plan.
- Weigh for a week to learn portions, then estimate.
- Keep going on the days you would rather not; those are the days the record needs.
Why: the calories are the least of it
The macros explain more of your record than the total. Protein read against your lean mass says whether what you are eating supports what you are training for; the research finds gains in lean mass from resistance training flatten above about 1.6 grams per kilogram a day (Morton 2018). Carbohydrate read against your glucose is the meal library: every logged meal gets its sensor response, and the surprises are the point. Fat read against your lipid panel is a conversation over months. Timing read against your sleep and your overnight readings explains the high mornings: a late dinner raised overnight glucose in healthy volunteers (Gu 2020). Eir reads all of it when you ask why a number moved, and the meal comparison cannot compare a meal you did not log.
Why: it makes the energy engine possible
VT's estimate of what you burn is built from your weight against your log, and it needs 29 of the last 36 days with both before it will say anything. Without the log there is no estimate, only the formula everyone else uses, and the Weight Loss Plan has nothing to set a deficit from. Even if weight is not your aim, the estimate is the number behind the energy-balance view.
Why consistency beats precision
Logs are imperfect everywhere: in the OPEN study, adults under-reported their energy intake by 12 to 20 percent on careful 24-hour recalls and by 31 to 38 percent on questionnaires, measured against doubly labeled water (Subar 2003). VT's engine assumes your log is imperfect and estimates how imperfect it seems; what it cannot handle is a log that is careful on Monday and absent on Saturday, because the arithmetic runs on windows of weeks and an absent day is a hole, not a zero. A log that is always about 15 percent low is a usable series; a log that is sometimes complete and sometimes empty is not.
What to log when time is short
The protein source, the carbohydrate source, the time, and anything with alcohol in it. That is thirty seconds and most of the information.
Sources
- Morton RW, et al. Br J Sports Med 2018;52:376–84. doi:10.1136/bjsports-2017-097608
- Gu C, et al. Metabolic effects of late dinner in healthy volunteers. J Clin Endocrinol Metab 2020;105:2789–802. doi:10.1210/clinem/dgaa354
- Subar AF, et al. The OPEN study. Am J Epidemiol 2003;158:1–13. doi:10.1093/aje/kwg092
- Vitality Tracker, How Vitality Tracker estimates your energy expenditure, method note v1.0.