Numerous products and companies make claims like “boosts your metabolism,” “helps burn fat,” ect. Is it true? What is your metabolism and what is it responsible for?

 

The term metabolism refers to all of the chemical reactions that occur in the body to maintain homeostasis. Homeostasis is our optimal state of living; it is a dynamic balance of our internal environment that ensures proper functioning of our systems, organs, tissues, and cells.

 

Metabolism is often linked to “burning fat” because it indeed uses the fuel we provide through food to carry out all functions in the body. This fuel is usually carbohydrates and fat stored within various cells in the body.

 

Your Basal Metabolic Rate (BMR) is the minimum level of energy needed to sustain vital functions when the body is sedentary (think laying in bed after you’ve just woken up). Whereas your Resting Metabolic Rate (RMR) is the level of energy required with low levels of functioning (think sitting on the couch reading).

 

Your resting metabolism is using fuel stored in the body, usually as fat, to carry out functions while you sit on the couch- yes that’s right, you’re burning fat while sitting on the couch. At low levels of activity your body is using mostly fats as fuel; while at high intensities of exercise your body is using mostly carbohydrates.

 

Resting metabolic rate can be increased or decreased by numerous influences in the body. A large determinant of a high metabolic rate is the amount of lean body mass, or muscle, the body possesses. Muscle requires a lot of energy at rest to maintain homeostasis. Namely, sodium/potassium pumps in the muscles must constantly be pumping ions to preserve their membrane potentials. Thus the easiest way to increase your RMR is to increase muscle mass through resistance training.

 

Stress also increases RMR. While building more muscle mass is surely a healthy way to increase RMR, maintaining high levels of stress is not. Sustained stress often causes our bodys’ to seek comfort in other ways, usually in the form of overeating. Thus high levels of stress are often detrimental to our overall balance of energy.

 

Many products that contain caffeine claim to “boost metabolism.” Caffeine is a stimulant that works on the central nervous system to create sympathetic or “fight or flight” responses. Thus caffeine can create a short-term and unsustainable increase in RMR.

 

There is a lot of discussion about whole foods and herbs that have the potential to increase RMR. Many of these claims have not been supported in research. There was one relevant study published in 2005 by Logan and Spriet that showed omega-3 fatty acid supplementation increased resting metabolic rate in older women. While the test subjects where taking omegas in capsule form, the same oil can be found in fish such as salmon.

 

Your Total Energy Expenditure (TEE) is just as it sounds; the total amount of energy you burn in a day. Three components make up your TEE:

 

1) RMR

2) Thermic effect of food: the energy it takes to digest food (very minimal)

3) Physical activity: this ranges from sitting at your desk working, to high intensity exercise; any movement you produce throughout the day.

 

For sustainable health one must balance their TEE with the amount of energy consumed through food. This is often the downfall of many seeking to alter or maintain body weight. The most effective way of balancing energy-in versus energy-out is eating an abundance of plant-based foods and getting as much natural movement each day. You shouldn’t need to count the calories you eat or the calories burned during exercise. If you honor your body with wholesome food and healthy movement, the rest will take care of itself!

 

REFERENCES

Grosvenor, M. B., & Smolin, L. A. (2015). Visualizing nutrition: Everyday choices (Third ed.). Hoboken, NJ: Wiley.

Kazaks, A. G., & Stern, J. S. (2013). Nutrition and obesity. Burlington, MA: Jones and Bartlett Learning.

Kenney, W. L., Wilmore, J., & Costill, D. (2012). Physiology of sport and exercise (Fifth Edition ed.). Champaign, IL: Human Kinetics.

Logan, S. L., & Spriet, L. L. (2015). Omega-3 fatty acid supplementation for 12 weeks increases resting and exercise metabolic rate in healthy community-dwelling older females. Plos One, 10(12), 1-18. doi:10.1371/journal.pone.0144828