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Question: Does frozen food help you burn more calories than food that has been heated?
This is a frequently asked question. The simple answer is "yes, consuming frozen food helps with burning more calories, as compared to their room-temperature counterparts." However, if I were to answer the underlying question: Does this dietary practice help with weight loss? The answer is: It depends.
Let's explore the science of how frozen food contributes to calorie burning to explain my last answer. Consuming a cold food, such as cold water or frozen yogurt, decreases the core body temperature. This change is detected by internal sensors that relate to the hypothalamus in the brain. The hypothalamus acts as a thermostat with a set point for body temperature at around 37 degrees C (98.6 degrees F). When frozen food causes a drop in the core temperature, the hypothalamus intitiates a warming reponse aimed at reducing heat loss and increasing heat production. The intensity of the response is relative to the extent of the deviation from the set point. Blood vessels constrict to prevent heat loss and heat production increases via shivering thermogenesis, which involves muscle contraction to release heat. The energy supplied to the shivering muscle mostly comes from muscle stores of carbohydrates and fats. Thus, because the shivering muscle is oxidizing fuel, we can affirm that the cold food does increase calorie burning.
Let's look at why cold food does not always lead to weight loss. In order to achieve weight loss from body fat, it is essential to create a deficit over a period of time between calories we consume and calories we burn (also known as metabolic rate). If our caloric intake is higher than the energy needed for our age, height and level of activity, eating or drinking a modest amount of frozen/cold food contributes minimally to an increase in metabolic rate. No weight loss could be achieved. If we're consuming the right amount of calories and engaging in an active lifestyle, however, then this dietary practice, along with others might add to energy expenditure and promote weight loss.
It is worth mentioning that hypoglycemia or low blood sugar hinders shivering themogenesis, due to the inhibition of cold-sensitive neurons of the hypothalamus, which rely on blood sugar for activity. Thus, reducing food intake for weight loss purpose (which might cause a decrease in blood sugar in some dieters) and consuming cold food for that purpose will not support calorie burning from shivering thermogenesis.
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