NEATNon-Exercise Activity Thermogenesis
Calories burned through everyday movement outside of formal exercise.
NEAT (Non-Exercise Activity Thermogenesis) is everything you burn through movement that nobody would call exercise: walking to the shops, standing on a train, carrying washing upstairs, cooking, pacing on the phone and fidgeting through a meeting.
It matters because it is usually much larger than the gym session it gets compared with. An hour of training might cost a few hundred calories; the other fifteen waking hours decide whether you spent another two hundred or another eight hundred, and the gap between an office worker and a postal worker dwarfs anything a workout adds.
It also varies enormously between people, which is part of why two people on the same food and the same programme get different results without either of them being dishonest.
The awkward part is that it moves against you. When calories drop, spontaneous movement tends to fall without any decision being made: fewer steps, more sitting, less fidgeting, quieter days. That is one of the mechanisms behind metabolic adaptation, and it is invisible precisely because it is not a choice you notice making.
It is also the easiest thing to defend deliberately. A daily step target is the simplest instrument anyone has for this, because it converts an unconscious drift into a number you can see. Walking is the least glamorous and most reliable tool in fat loss.
None of this makes structured exercise optional. Training builds the strength and fitness that protect your later decades; NEAT mostly moves the energy ledger. Both matter, for different reasons, and confusing them is how people end up training hard and still stalling.
In practice, watch steps rather than trying to measure NEAT directly, keep them roughly constant while dieting, and use our steps to calories calculator for a rough sense of what a change in daily movement is worth.