Open Feedback Dialog

How Much Do You Know About Your Metabolism?

By Angela Harden-Mack, MD ABOM


Do you blame a sluggish metabolism for your weight gain? Turns out this may be more than a flimsy excuse for packing on a few extra pounds. Take this brief quiz to test your basic knowledge of metabolic rate.


True or False An older individual will have a higher metabolic rate compared to a younger individual.

Answer: False Older individuals have decreased levels of growth hormone, decrease in muscle mass and more fat tissue, all impacting and lowering the metabolic rate.


True or False A man and woman of the same age will have the same metabolic rate. 

Answer: False Men generally have a higher percentage of fat-free mass or lean muscle and therefore, have higher metabolic rates compared to women.


True or False The metabolic rate declines with weight loss.

Answer: True Weight loss causes a decline in total energy needs and lower muscle mass results in a lower metabolic rate.


True or False Eating 4 small meals throughout the day burns more calories compared to eating a larger meal once or twice a day.

Answer: True The energy used to metabolize food is called the thermic effect of food. Eating more often during the day utilizes more energy compared to eater fewer times a day.


If you answered all of these questions correctly, then you probably have a good understanding of the importance of your metabolism. If you missed a few questions, then pay careful attention to the information that follows. Your health and weight-loss success may depend on it.


Keep in mind, the best weight loss plan includes specific goals and customized recommendations based on personal daily energy needs and metabolic rate. Knowledge of daily energy needs and metabolic rate provides the opportunity to adjust caloric intake and energy expenditure in such a way that makes the weight loss plan effective and practical.


Daily energy needs are supplied from energy produced by the metabolism of food and/or release of energy from the body’s energy stored in fat tissue. Total Energy Expenditure (EE) is the amount of energy a person uses in one day. Energy expenditure is the total of the Resting Metabolic Rate (RMR), Physical Activity (PA) and Thermic Effect of Food (TEF). Resting Metabolic Rate (referred to as Metabolic Rate in this article) contributes 65-75% of EE and is the amount of energy consumed at rest to complete functions such as breathing, repair, and heat generation. Physical Activity, defined as exercise and non-exercise activities, contributes 15-20% of EE. Food metabolism, TEF contributes 5% of EE.


Weight loss plans are not ‘one-size-fits- all’. Many individuals try to use generic plans that are not the best fit for their needs and goals. Frustration and disappointment set in when goals are not realistic. This leads to results that are suboptimal and the plan is not sustainable. Learning basic information regarding your daily energy needs and metabolic rate is beneficial to create a realistic, tolerable and sustainable weight loss plan. Here are five basic things you should know about metabolic rate:

1. Metabolic Rate is unique to each individual and is impacted by gender, age, body composition, medications, and various levels of hormones such as sex hormones and growth hormone.


2. Metabolic Rate is higher when younger compared to advanced ages. The normal aging process results in a 1-2% decline each decade due to the normal gradual decline in levels of growth hormone, loss of muscle and increase in fat tissue.


3. Metabolic Rate is impacted by body composition which describes the percentage of fat mass and fat- free mass. Muscle is more metabolically active (burns more calories) compared to fat tissue. The greater the amount of fat free mass, the higher the metabolic rate.


4. Metabolic Rate declines with weight loss. As weight decreases metabolism becomes more efficient and the total energy need decreases. Regular exercise can minimize the normal decline associated with weight loss.


5. Metabolic Rate can be increased. An easy way to increase metabolic rate is by increasing the amount of energy expenditure related to the thermic effect of food. Food metabolism requires energy, and a greater amount of energy is used by eating smaller meals more often compared to eating one or two larger meals during the day.


Remember, weight loss is not easy, but creating a plan with specific goals related to your personal energy needs and metabolic rate can make it easier. To learn more about metabolic rate and its use in weight loss, and to have your metabolic rate calculated or measured contact a medical provider and/or healthcare professional specializing in weight management.