Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition characterized by persistent patterns of inattention and/or hyperactivity-impulsivity. This disorder alters how individuals regulate attention, control impulses, and manage activity levels. Given the visible restlessness and energy often associated with the condition, a frequent question is whether people with ADHD expend more energy, or burn more calories, compared to their neurotypical peers. Understanding the physiological and behavioral links between ADHD and metabolism helps answer this question.
Energy Expenditure in ADHD
The total amount of energy a person uses daily is known as Total Energy Expenditure (TEE), which includes energy for basic life functions, digesting food, and physical activity. The largest component of TEE is the Basal Metabolic Rate (BMR), the calories burned while the body is at complete rest. Research suggests that overall TEE is higher in individuals with ADHD, primarily due to increased movement throughout the day.
While heightened activity accounts for most of the increased calorie burn, some studies indicate that Resting Energy Expenditure (REE), which is closely related to BMR, can also be elevated in medication-naive children with ADHD. For instance, one study found that REE was, on average, 6.5 kilocalories per kilogram of fat-free mass per day higher in boys with ADHD compared to a control group. This suggests a systemic metabolic difference that is not solely explained by visible restlessness. This higher overall daily energy demand means people with ADHD tend to have a higher daily caloric output.
Fidgeting and Increased Calorie Use
The most significant contributor to a higher TEE in ADHD is Non-Exercise Activity Thermogenesis (NEAT). NEAT is the energy expended for all spontaneous, low-level movements outside of sleeping, eating, or structured exercise, such as tapping a foot, shifting posture, or pacing. For individuals with hyperactive or combined-type ADHD, restlessness translates directly into a constant cycle of these small movements.
This persistent physical activity substantially contributes to the total daily caloric burn. Studies show that energy expended through NEAT can account for an extra 100 to 800 calories per day, depending on the movement’s intensity and duration. Fidgeting while sitting or standing has been observed to increase calories burned by approximately 29% to 38% compared to a completely still position. This “fidget factor” is an unconscious mechanism that raises the body’s energy output throughout the day.
The constant need to move is often felt as an internal drive to seek stimulation. Children with ADHD who engage in more spontaneous bodily activity have been shown to perform better on certain cognitive tasks, suggesting that movement serves a self-regulatory function that also expends energy. This behavior is the primary mechanism by which individuals with ADHD may burn hundreds of extra calories daily compared to their less restless peers.
How Stimulant Medications Affect Metabolism
Stimulant medications for ADHD, such as methylphenidate and amphetamines, directly influence metabolism through their effect on the central nervous system. These drugs function as sympathomimetics, mimicking the body’s “fight-or-flight” response and leading to increased physiological arousal.
The drugs increase the release of neurotransmitters like dopamine and norepinephrine, triggering a metabolic cascade. This process elevates the basal metabolic rate, promoting thermogenesis (heat production) and stimulating the mobilization of stored energy, including fat and glucose. This drug-induced metabolic increase contributes to the common side effect of appetite suppression, where individuals experience reduced hunger signals.
While medication increases the resting metabolic rate, it often decreases the activity component of TEE. By improving focus and reducing the hyperactivity that drives NEAT, stimulants reduce overall physical movement. One study found that children on medication showed a 4% to 8% lower TEE compared to when unmedicated, a reduction attributed entirely to decreased physical activity. This demonstrates a complex interplay where medication increases metabolic rate while simultaneously reducing behavioral energy expenditure from movement.
The Brain’s Baseline Energy Requirement
A less obvious factor in energy expenditure is the brain’s internal metabolic demand. The brain is an energy-intensive organ, consuming about 20% of the body’s total energy. In ADHD, functional differences in the brain may lead to a higher baseline energy requirement.
ADHD involves dysregulation in neurotransmitter systems, particularly dopamine, which governs attention and motivation. Brain regions responsible for executive functions, such as the prefrontal cortex, may require more effort to maintain focus or inhibit impulsive actions. This increased cognitive effort translates into a higher metabolic cost within the brain itself.
Neuroimaging research suggests that maintaining attention or controlling behavior may require more sustained activity or inefficient neural processing in the ADHD brain. This consumes more glucose and oxygen, the brain’s primary energy sources. Therefore, the internal effort to manage attention and inhibition may elevate the brain’s resting metabolic rate, contributing to a higher overall REE, even when the individual is still and unmedicated.