NEAT — The Calories You Burn Just By Existing

NEAT stands for non‑exercise activity thermogenesis — the energy you burn doing everything that is not formal exercise, sleep or basic organ function. It’s the pacing while you talk on the phone, the way you stand instead of sit, the half‑conscious stretch to put things away, the little “I’ll just walk there” choices that add up across the day.

If your total daily energy use is a pie, NEAT can be a surprisingly large slice. Two people with the same body size and the same workout routine can differ by hundreds of calories a day just from NEAT. One body naturally potters, fidgets, takes the stairs; the other sinks into the chair and barely moves unless scheduled.

Here’s the twist: NEAT is not just about personality or “discipline”. It is heavily regulated by the brain, especially weight‑regulating circuits in the hypothalamus and reward pathways like the mesolimbic-reward system. When your body senses energy deficit — falling leptin, shifting insulin, rising hunger hormones like ghrelin — it often turns NEAT down. You feel more tired, movement feels less appealing, and your natural fidget drops. That’s one arm of adaptive-thermogenesis.

Weight‑loss drugs like GLP‑1 agonists (for example semaglutide or tirzepatide) can influence NEAT indirectly. By dialing down food noise and hunger, they may make it easier to move more, or at least not crash NEAT as hard during a deficit. But if the brain still thinks your old set-point is “home base”, it may quietly trim NEAT over time to defend that level, even when appetite is better behaved.

On the flip side, when energy availability is high and your body feels safe, NEAT often drifts upward: you unconsciously stand more, pace more, talk with your hands, volunteer for that extra walk. You don’t decide this in a spreadsheet; your nervous system is constantly nudging behavior to keep intake and expenditure in a range it considers reasonable.

Why It Matters

NEAT is one of the reasons “just eat 500 calories less and you’ll lose 0.5 kg a week forever” rarely works as advertised. The body tends to leak calories on the other side of the ledger by subconsciously cutting movement. Seeing NEAT as a hormone‑tuned, brain‑driven dial — not a moral failing — makes plateaus and post‑diet regain easier to understand and less shame‑soaked.

Practically, this means that long‑term weight change is less about punishing workouts and more about building a life where movement is woven into the day: walking meetings, standing up between tasks, choosing environments where you naturally move more. Medications can help on the appetite side, but keeping NEAT alive is part of defending new weight in a world where your biology would love to drift back up.

Closing Line

Think of NEAT as the quiet background soundtrack of your metabolism — you don’t always notice it changing, but when the volume drops, your energy balance does too.