NEAT
NEAT — Non-Exercise Activity Thermogenesis (NEAT) is the energy expended for everything other than sleeping, eating, or formal exercise — including standing, walking to the mailbox, fidgeting, typing, household chores, and occupational activity. NEAT can vary by 2,000 kcal per day between individuals of similar body size and is the most variable component of total daily energy expenditure.
What is NEAT?
Non-Exercise Activity Thermogenesis (NEAT) is the energy expended for all physical activity that is not structured exercise, sleep, or eating. This includes:
- Walking around the office, parking lot, or grocery store
- Standing rather than sitting
- Fidgeting, foot-tapping, posture shifts
- Cooking, cleaning, gardening, child care
- Occupational activity (waitstaff vs. desk worker)
The concept was popularized by Dr. James Levine at the Mayo Clinic, who demonstrated in landmark studies that NEAT can vary by up to 2,000 kcal/day between adults of similar mass and is a major determinant of obesity susceptibility under controlled overfeeding.
How does NEAT work?
NEAT is partially under voluntary control (you can choose to take the stairs) but is also strongly modulated by non-conscious mechanisms. In a famous Mayo Clinic overfeeding study, lean adults who resisted weight gain when overfed by 1,000 kcal/day did so largely by spontaneously increasing NEAT — without consciously exercising more. Adults who gained weight readily had blunted NEAT responses.
NEAT is suppressed during energy deficit — one mechanism of adaptive thermogenesis that frustrates dieters. People who lose 10%+ of body mass commonly experience reduced NEAT (more sitting, less fidgeting, slower walking pace) that they may not consciously notice.
Why NEAT matters in weight management
For most adults, NEAT is the single largest source of error in TDEE estimation because:
- Activity-factor multipliers (1.2 sedentary → 1.9 very active) are crude
- Two desk workers can have substantially different NEAT just from posture habits
- NEAT changes during dieting, mostly downward
Practical implications for app-based tracking:
- Adding standing time, walking meetings, or “exercise snacks” can meaningfully raise TDEE
- A cheap pedometer or wearable can capture step count, the most measurable NEAT proxy
- During a deficit, deliberate NEAT preservation (e.g., maintaining step count) may protect RMR and improve outcomes
See also BMR and the thermic effect of food.