Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period. It is the sum of three main components: Basal Metabolic Rate (BMR), the Thermic Effect of Food (TEF), and Physical Activity Energy Expenditure (PAEE). While BMR is often the largest contributor, accounting for 60–75% of daily calories burned, it is the physical activity component that exhibits the most significant variation among individuals. This variability is largely driven by Non-Exercise Activity Thermogenesis, or NEAT.
Understanding the Components of Total Daily Energy Expenditure
Basal Metabolic Rate (BMR)
BMR represents the energy your body uses to perform basic physiological functions at rest, such as breathing, circulation, and cell production. It is the energy required to simply stay alive. BMR is influenced by factors like body size, age, gender, and muscle mass, but it is relatively stable from day to day for a single individual. Although it is the largest portion of daily energy expenditure, its inter-individual variation is significantly less than that of physical activity.
Thermic Effect of Food (TEF)
TEF, also known as diet-induced thermogenesis (DIT), is the energy your body expends to digest, absorb, and process the nutrients from the food you eat. This component typically accounts for about 10% of total daily energy expenditure and is also relatively stable. The specific macronutrient composition of a meal can influence TEF, with protein having the highest thermic effect.
Physical Activity Energy Expenditure (PAEE)
PAEE covers all energy expended through physical movement and is further divided into two sub-components: Exercise Activity Thermogenesis (EAT) and Non-Exercise Activity Thermogenesis (NEAT). EAT refers to planned, structured exercise, such as going to the gym or running. NEAT, in contrast, includes all other movement throughout the day that is not formal exercise. It is within this PAEE component, specifically NEAT, that we see the greatest variability from person to person.
The Power and Variability of Non-Exercise Activity Thermogenesis (NEAT)
NEAT is the energy expended for everything we do that is not sleeping, eating, or sports-like exercise. This includes everything from fidgeting and maintaining posture to walking to the car, doing yard work, and performing household chores. The energy burned through these small, often unconscious, movements adds up significantly over time.
What makes NEAT the most variable component is the vast difference in lifestyle and behavioral patterns between individuals. For example, a person with a desk job who watches TV in the evening will have a vastly different NEAT than a construction worker or a stay-at-home parent who is constantly on the move. Studies have shown that NEAT can vary by up to 2000 kilocalories per day between individuals of similar size, age, and body composition.
Key Factors Influencing NEAT
- Occupation: The type of work someone does is a primary driver of NEAT variability. A physically demanding job, like manual labor or agriculture, can lead to substantially higher daily NEAT compared to a sedentary office job.
- Leisure Activities: How people spend their free time greatly affects their NEAT. An individual who enjoys hiking or gardening will burn significantly more calories through NEAT than someone who prefers passive hobbies like watching television.
- Genetics: Some studies suggest there may be a genetic component to an individual's natural tendency to fidget or spontaneously move. These differences in involuntary movement contribute to the variability in NEAT.
- Environmental Factors: Societal trends toward mechanization and labor-saving technology have systematically decreased NEAT on a population level. The availability of sidewalks, stairs, and parks in an environment can also influence activity levels.
- Adaptive Thermogenesis: In response to changes in energy balance (e.g., overfeeding or calorie restriction), the body can alter NEAT levels to compensate. However, the magnitude of this adaptation is highly individual, further adding to NEAT's variability.
NEAT vs. EAT: A Comparison
| Characteristic | NEAT (Non-Exercise Activity Thermogenesis) | EAT (Exercise Activity Thermogenesis) |
|---|---|---|
| Type of Activity | Unstructured, spontaneous, and everyday movements. Examples: fidgeting, walking, gardening, cleaning. | Planned, structured, and intentional exercise. Examples: running, weightlifting, cycling, gym classes. |
| Variability | High variability between individuals, contributing most to inter-individual differences in TDEE. | Can vary, but is often a smaller, more consistent contribution for most of the population, with high intensity being limited to specific time frames. |
| Adherence | Requires incorporating small, consistent changes into daily habits, which can be easier to maintain long-term for some people. | Requires specific motivation, time commitment, and discipline, which can lead to lower adherence rates over time. |
| Impact on TDEE | Can account for a wide range of TDEE, from a low of 6–10% in sedentary people to 50% or more in highly active individuals. | Often a smaller contributor on a population level, but can be a significant part of TDEE for dedicated athletes. |
How to Increase Your NEAT
Increasing your NEAT is a practical strategy for boosting your daily energy expenditure and supporting weight management. It doesn't require hitting the gym but rather a conscious effort to move more throughout the day.
Here are a few simple ways to increase your NEAT:
- Use a standing desk: Alternating between sitting and standing can increase calorie burn and encourage more movement.
- Take the stairs: Choosing stairs over elevators is a classic, simple way to add more activity to your day.
- Walk during meetings and phone calls: If feasible, pace around your office or home while on the phone or in a virtual meeting.
- Incorporate active chores: Stand while folding laundry, hand-wash dishes, or do some gardening to add movement to your routine.
- Fidget more: Tap your feet, shift your posture, and move around, as this unconscious movement can add up to a notable calorie burn.
- Park farther away: Opting for a parking spot at the back of the lot can add extra steps to your day.
Conclusion: Why Focusing on NEAT Matters
While the largest portion of our daily energy expenditure is dedicated to BMR, NEAT is the component that offers the most potential for significant, day-to-day variation for most people. The cumulative impact of minor, low-intensity movements can create a notable energy deficit over time, making it a critical, yet often overlooked, factor in weight regulation and overall health. Small, consistent increases in NEAT are a sustainable way to increase TDEE and improve metabolic health, especially for those with sedentary lifestyles. By understanding the power of NEAT, individuals can better manage their energy balance and work towards their health goals without relying solely on intense, structured exercise.
To learn more about NEAT's role in human energy expenditure, read this detailed review from the NIH
How to Increase Your NEAT
Increasing your NEAT is a practical strategy for boosting your daily energy expenditure and supporting weight management. It doesn't require hitting the gym but rather a conscious effort to move more throughout the day.
Here are a few simple ways to increase your NEAT:
- Use a standing desk: Alternating between sitting and standing can increase calorie burn and encourage more movement.
- Take the stairs: Choosing stairs over elevators is a classic, simple way to add more activity to your day.
- Walk during meetings and phone calls: If feasible, pace around your office or home while on the phone or in a virtual meeting.
- Incorporate active chores: Stand while folding laundry, hand-wash dishes, or do some gardening to add movement to your routine.
- Fidget more: Tap your feet, shift your posture, and move around, as this unconscious movement can add up to a notable calorie burn.
- Park farther away: Opting for a parking spot at the back of the lot can add extra steps to your day.
Conclusion: Why Focusing on NEAT Matters
While the largest portion of our daily energy expenditure is dedicated to BMR, NEAT is the component that offers the most potential for significant, day-to-day variation for most people. The cumulative impact of minor, low-intensity movements can create a notable energy deficit over time, making it a critical, yet often overlooked, factor in weight regulation and overall health. Small, consistent increases in NEAT are a sustainable way to increase TDEE and improve metabolic health, especially for those with sedentary lifestyles. By understanding the power of NEAT, individuals can better manage their energy balance and work towards their health goals without relying solely on intense, structured exercise.
To learn more about NEAT's role in human energy expenditure, read this detailed review from the NIH
