A single logged day can look tidy. Breakfast on time, vegetables at dinner, a sensible snack. That snapshot is not the same thing as a pattern.
Most people eat differently on weekdays and weekends. Travel, late finishes, and shared meals change portions and food choices. Nutrient shortfalls and excesses often show up across several days, not in one sitting.
A diary is useful when it is ordinary. Log what you actually ate, including the days that were rushed. Looking back across a week makes it easier to see whether fibre, iron, calcium, or protein are regularly low — or whether sodium is regularly high.
You do not need a perfect record. You need a record that resembles your week. That is the difference between a diary and a performance.
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