Where does our energy comes from? Where does energy go?

by Roxy zhang

Where does our energy comes from? The food we eat contain nutrients that provide energy the body need, and most of the nutrients in food mainly comes from three major groups: carbohydrates, fats and proteins. Carbohydrates are mainly present in food such as rise, bread and starchy vegetables. Fats are usually in food like meat, liquid oil, buffer and whole-fat milk. And proteins are normally in foods like meats, legumes and some grains.

Then where does our energy go? There are three components of energy expenditure: BMR(basal metabolic rate) the sum total of all involuntary activities that are necessary for life except digestion and voluntary activities; TEF(thermic effect of food) increase in BMR due to eating; physical activity/voluntary activity intentional activity like biking, walking, running  and sitting. etc. 

The question that might be the uppermost in people's mind is" which one is the largest component of energy expenditure?" about half of people will choose physical activity(according to in-class activity in HNF 150)but the answer is BMR. In facts, the component of energy expenditure from the biggest to lowest are 60-65% BMR; 25-35% physical activity and 5-10% TEF. So which factor effects BMR and determines how much energy should we consume each day? BMR is mainly controlled by hormone produced by thyroid gland. And the hormones vary about ages, height, stress, growth, starvation/fasting/, malnutrition, body composition, fever and environment temperature. etc.

In conclusion, there are three major nutrients groups that provide our body nutrient: carbohydrates, fats and proteins. And three main components of energy expenditure are: BMR, TEF and physical activity.

the first Photo comes from spoonuniversity.com/lifestyle/how-tracking-macros-can-help-you-get-more-out-of-your-workout.
the second photo comes from www.wellbuiltstyle.com/energy-balance-and-your-body-weight/.