Non-Exercise Activity Thermogenesis (known as NEAT and sometimes referred to as Spontaneous Physical Activity or SPA) is the movement you do during the day which doesn’t constitute formal exercise done for its own sake – this includes commuting to work, walking around your house/office, fidgeting, playing with the kids and even low-level activities like shaking your leg while sat on the couch and changing your sleeping position.
NEAT accounts for a huge amount in the TDEE variance between individuals. Consider two individuals who have the same statistics, but one of them works in an office and the other works as a postman. For simplicity let’s assume they would have a TDEE of 2400 if they were completely sedentary – 100kcal per hour.
The office worker will be burning approximately 8% above TDEE per hour at his job shifting position, thinking and typing. That means that each hour of his 8-hour day he burns 108 calories, totalling 864 calories from 9-5. The postman would be walking an average of 1-2mph during that time (accounting for breaks, for example) which equates to an increase of around 100-150% according to Levine et al, meaning that he’d be burning at least 200 calories per hour, or 1600 calories during his workday. As you can see, with a small change in lifestyle, increased NEAT can easily result in a TDEE difference of 1000 calories or more between individuals, which is huge.
Increasing NEAT is often associated with improved body composition and health, whereas increased EAT is typically not. This could be because increased EAT is generally associated with a decrease in NEAT, and as such, we would say that daily activity is typically far more important than strict exercise when it comes to predicting total daily energy expenditure. We will return to the impact that NEAT can have on weight loss later in this module.