What is NEAT? Non-exercise activity thermogenesis

Most people think of calorie burn as the gym. For most of the population, the gym is a small slice of the day. The rest of it, the walk to the car, the hours on your feet, the stairs, the laundry, burns more. That is NEAT. It was studied most closely by James Levine and his colleagues at the Mayo Clinic, and it explains much of why two people of the same size can need very different amounts of food.

Where NEAT fits in daily energy use

Daily energy use, or TDEE, has four parts: basal metabolic rate, the thermic effect of food, exercise and NEAT. BMR is fairly predictable from body size. The thermic effect of food is about 10% of what you eat. Exercise depends on your plan. NEAT is everything left, and it ranges from a small slice of the day for someone who sits for work to half or more of daily energy for people with very active jobs.

Why it varies so much

NEAT depends on your job, your commute, your home, your habits and, it seems, your biology. Levine’s work estimated that it can differ by up to about 2,000 kcal a day between people of similar size.

• Occupation: A shift on your feet in a warehouse, a kitchen or a hospital ward costs far more than eight hours at a desk.
• Environment: A city you walk around, stairs at home, a dog that needs walking, small children to chase.
• Habit and posture: Standing instead of sitting, pacing on calls, fidgeting. Small movements, repeated all day, add up.
• Biology: Some people seem to move more by instinct, especially when they eat more.

That last point comes from one of the best-known overfeeding studies. In 1999, Levine and colleagues fed 16 non-obese adults 1,000 kcal a day above their needs for eight weeks. Fat gain ranged roughly tenfold, from under half a kilogram to over 4 kg. The biggest predictor was NEAT: some people increased their daily non-exercise movement by close to 700 kcal, while others did not increase it at all.

Steps as a proxy

You cannot measure NEAT directly outside a lab, but steps are a decent stand-in. Walking is the biggest piece of NEAT for most people, and almost every phone and watch counts it.

Here is how much a step habit is worth. The Compendium of Physical Activities rates walking at about 3 mph at 3.5 METs and sitting quietly at 1.3 METs, where one MET is roughly 1 kcal per kg of body weight per hour. At a typical pace of about 100 steps a minute, 5,000 extra steps take 50 minutes. For a 75 kg person, the extra over sitting is (3.5 − 1.3) × 75 × 50 ÷ 60, or about 138 kcal a day. Over a week that is close to 1,000 kcal, from walking alone.

MET values are averages, so treat that as a ballpark. Heavier people and faster walkers burn more per step, lighter people and slow strolls less. The direction is reliable even when the exact number is not.

Why NEAT drifts down in a deficit

When you eat less, your body tends to move less, and you may not notice. You sit instead of stand, take the elevator, pace less on calls, skip the walk at lunch. Studies of calorie restriction have found that spontaneous activity often falls while people diet, and it is one reason weight loss slows more than the 7,700 kcal per kg rule predicts.

Run the same arithmetic in reverse. If the 75 kg walker above drops from 9,000 steps a day to 5,000, that gives back about 110 kcal a day, a quarter of a 440 kcal calorie deficit. The fix is not glamorous: track steps, and keep a floor. If your average falls while you diet, add a walk back before you cut more food.

Ways to raise NEAT without trying hard

• Walk the calls: Take phone and video calls standing or walking.
• Add distance on purpose: Park further away, get off a stop early, take the stairs for a floor or two.
• Break up sitting: Stand and move for a few minutes every half hour or so.
• Walk after meals: Ten minutes after lunch and dinner adds up to more than two hours a week.
• Do the chores: Cooking, cleaning, carrying groceries and gardening all count.

Common mistakes

• Overrating the gym: Three hard sessions a week can be smaller, in energy terms, than the gap between a sitting job and a standing one.
• Trusting calorie readouts: Watches estimate energy from heart rate and motion and can be well off. A step count is a steadier number to follow.
• Walking more and eating it back: More movement can bring more hunger. Watch the weight trend, not just the steps.

How FORM uses it

FORM reads your steps from Apple Health or Health Connect, along with active calories if a watch or ring syncs them. Steps count toward your daily Health Score, up to 10,000 a day. In Circles, friends can see each other on a daily steps leaderboard, which is a light nudge to take the long way home.

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