The question of whether the simple act of chewing food burns calories has a straightforward answer: yes, but the amount is extremely small. The mechanical process of breaking down food in the mouth, known as mastication, requires energy expenditure from the muscles involved. This activity is a minor contributor to the body’s total daily energy output. The energy cost of chewing is negligible when compared to the total calories consumed during a meal.
The Mechanics of Mastication
The energy used during chewing comes directly from the contraction of the powerful muscles that operate the jaw. The primary muscles involved in this process are the masseter and the temporalis. The masseter is the strongest muscle in the human body by weight, and it is responsible for the forceful elevation of the mandible, which crushes the food bolus.
The temporalis muscle, which covers the side of the head, also plays a significant role in closing the jaw. Its fibers assist in retracting the mandible, which helps extend the grinding path of the teeth for maximum mechanical efficiency. This coordinated action requires a continuous supply of energy. The energy expended is directly proportional to the force applied and the duration of the chewing process.
Mastication Versus the Thermic Effect of Food
The minimal calories burned by the physical act of chewing must be distinguished from the much larger energy expenditure that occurs after swallowing. The vast majority of the calorie burn associated with eating is known as the Thermic Effect of Food (TEF). TEF represents the energy required by the body to digest, absorb, transport, and store the nutrients consumed in the meal.
This post-swallowing metabolic cost typically accounts for about 10% of the total calories ingested in a mixed diet. The specific macronutrient composition heavily influences the size of the TEF. Digesting protein requires the most energy (20 to 30% of protein calories), followed by carbohydrates (5 to 10%), while dietary fats require the least energy (0 to 3%). The energy spent in moving the jaw is only the first, and least substantial, step in this complex process.
Quantifying the Caloric Effect
The caloric burn from mastication is minor, typically measured in single digits per hour. Studies monitoring the metabolic rate during continuous chewing, such as with gum, suggest an expenditure of approximately 8 to 11 calories per hour. Even aggressive chewing of tough foods may only increase the rate to 15 to 20 calories per hour.
To put this into perspective, the energy burned by chewing for one hour is less than one-tenth of what a person burns during a low-intensity activity. A 150-pound person burns about 150 calories per hour simply standing still, and approximately 210 calories during an hour of light walking. Consequently, while chewing does technically burn calories, the expenditure is too small to be a meaningful component of a weight loss or fitness strategy.