Counting calories without weighing every meal

Weighing every item of food is accurate and almost nobody keeps it up. I did it for nine days and then stopped, which is roughly the average as far as I can tell.

The problem with abandoning it entirely is that estimates are not wrong at random. They drift in one direction. A generous handful becomes the new handful; a portion that was once a hundred grams becomes a hundred and forty without anyone deciding it should.

Measure the repeats, estimate the rest

Most people eat a small number of meals over and over. Mine came to eleven, covering the large majority of what I actually ate in a week. So I weighed those eleven once, carefully, wrote the numbers down, and estimated everything else.

• The repeated meals are accurate, and they are most of the intake.
• The one-offs are estimated, and the error on them is small in absolute terms.
• The whole thing takes about an hour, once.

Recalibrating

Every couple of months I re-weigh two or three of the staples without warning myself first. It is a reliably humbling exercise: the portion has usually grown. Ten minutes of checking undoes several weeks of drift.

What this method will not give you is precision. What it gives you is a number that is wrong by roughly the same amount every day, which is enough to see a trend - and the trend is the part you can act on.