How Does Metabolism Affect Weight Loss?

by Marixie Ann Obsioma
Published on January 15, 2020

Are you one of those people who attribute weight gain to slow metabolism? Or perhaps, you belong to the fortunate group of forever fatless people who never put on weight no matter how big their appetites are? 

We hear a lot of people claiming that the primary reason why getting rid of the extra pounds is so difficult has something to do with their metabolism being really slow and not because they eat a lot. 

In this article, we will get to the bottom of the following: What is the real score between rapid metabolism and weight loss? What role does metabolism play in weight gain?

Metabolism and Its Effects on the Body

Your body undergoes certain biochemical processes to convert what you consume into energy that can fuel your every day. These interconnected processes are called metabolism. In the Brittanica Encyclopedia, it is defined as the sum of chemical reactions that occur within a living organism’s cells (1). The energy that results from these processes is used for important body mechanisms and synthesis of new organic materials.

Even at rest, your body requires energy for all the “unseen” mechanisms in your body like breathing, blood circulation, hormone level adjustments, and cell growth and repair. The body consumes the calories from your food by converting it to the energy that supports these functions. 

Metabolism is divided into two categories (2): 

  • Catabolic reactions involve the breakdown of large organic molecules into smaller ones. Energy is then released from the chemical bonds affected during the process. 
  • Anabolic reactions are the opposite of catabolism. It involves the building up of smaller molecules into bigger ones. Some examples are combining of monosaccharides to create polysaccharides, fatty acids to create triglycerides, and amino acids to create proteins.

Factors That Drive Metabolism

Basal metabolism differs in every individual. However, there are certain factors that contribute to one’s metabolic rate, such as:

1. Body Composition and Body Size

People with more muscles tend to burn more calories when resting. It does not matter how much they weigh. So long as they have more muscles and less fat, their metabolic levels are higher. According to a study conducted on Hispanic children, body size and composition contributes to higher energy expenditure linked to childhood obesity (3). Minor players include thyroid hormones, adrenomedullary activity, and the sympathetic nervous system.

2. Gender

Women generally have more body fat and less lean muscles than men with the same weight and age. So men, obviously, have the upper hand when it comes to metabolism and calorie-burning abilities. Several years ago, researchers ignore gender as a determining factor of metabolic rate. A study was conducted aiming to observe the metabolic responses of both men and women to exercise (4). Women oxidize proportionately fewer carbohydrates and more lipids when doing endurance exercise than men. These differences were attributed to women’s higher concentration of estrogen levels. Women, however, do not carbohydrate load upon increasing dietary carbs as much as men.

3. Age

Metabolism slows down with age. An average adult loses around 8% of muscle weight every 10 years after turning 30 (5). One study even proved that upon reaching 80, your muscle weight becomes 30% less of what it was when you were 6 years younger (6).

4. Genetics

Uh-oh. Does this mean that you can’t do anything to improve your metabolism if you were created that way? One study explored the mixture of psychiatric and physical features of anorexia nervosa (7). Based on their study, genetics play a role in the metabolic origins of anorexia. 

What Influences Metabolism Rate?

Regardless of age, gender, body size and composition, and genetics, the basal metabolic rate is dependent on these four factors (8):

  • Resting Metabolic Rate (RMR) which indicates the number of calories you burn while sleeping or resting. RMR is the minimum amount needed by the body to stay functional.
  • Thermic Effect of Food (TEF) which covers the number of calories through food digestion and absorption. TEF takes up 10% of your burned calories daily.
  • Exercise determines the number of calories consumed during the exercise.
  • Non-exercise Activity Thermogenesis (NEAT) indicates the number of calories consumed while doing minimum physical activities including fidgeting, standing, and doing chores. Most lean people are fidgety (9). They tend to do so many movements when doing non-exercise activities causing them to burn more calories. It is hard to tell if their inclination to move around is programmed or acquired. 

The Relationship Between Weight and Metabolism

As stated earlier, you do not burn the same amount of calories as much as the person waiting in line behind you.  A study appropriately called Energy Balance Study (EBS) aimed to determine the connections of caloric intake with energy expenditures and how these two affect body weight and composition (10). Four hundred and thirty people, 208 men and 212 women, all under 21 to 35 years of age and with a BMI between 20 to 25 kg/m2 participated in the EBS study for 12 months. Energy balance is complicated and it is influenced by three factors:

  • The calories needed to maintain body functions (metabolism)
  • The calories burned through activity
  • The calories consumed

Metabolism is also influenced by the last two: physical activity and food processing. The digestion absorption, transportation, storage of food, physical activity, and NEAT are all determining factors of metabolism.

Metabolism may have a hand in weight gain, as proven in the following studies and researches done throughout the years:

  • Studies showed that obese people have about an 8% decrease in metabolic rate than people who were never obese (11).
  • When you age your metabolism process slows down along with the number of calories you burn while resting. Your sodium-potassium pumps and mitochondria are the driving forces of RMR (12). Both of these slow down as you age, also affecting metabolism. As proven by a study conducted on 27 young men and 25 old men, the pumps were found to be 18% slower in older adults. They burned up to 101 fewer calories in a day (13).

Some studies, however, contradict metabolism’s role in weight gain as observed in the following studies:

  • Obese people are shown to have higher total and resting metabolic rates than individuals who have a normal weight (14). 
  • Other studies back up this finding, given that obese people require more muscle mass to support their weight and facilitate their movements (14).
  • Some studies, however, state that metabolic rates are not dependent on muscle mass (15).

One thing is for sure, not everyone is created equally. While it is tempting to point the finger on metabolism for weight gain concerns, there is more to it than that. Weight gain is complicated. A combination of several physical factors like hormonal control, diet composition, and genetic makeup with environmental factors like sleep pattern, physical activity level, stress, and general lifestyle should be put into consideration.

All of these can cause an energy equation imbalance. You gain weight when you eat a lot and exercise less. Some people lose weight faster than other people. But, you need to understand that everyone loses weight when they create an energy deficit. This can be done by either consuming fewer calories or increasing your physical activity to burn more.

How Does Physical Activity Affect Metabolism?

You will never gain control of your basal metabolism, but you can control the number of calories you burn by working out and doing other forms of activities. By increasing your activity level, you burn more calories. Some people who are thought to have high metabolism are probably just physically active, anyway. Burning more calories can be done in a number of ways, such as:

1. Performing Cardio and Aerobic Exercises

Cardio workouts are the most effective means to burn calories. Examples are cycling, swimming, walking, and running. By incorporating at least 30 minutes of physical activity a day, you encourage your body to burn more fat. Most people who want to lose weight always involve aerobic exercises in their workouts.

2. Practicing Resistance Training

Weightlifting at least twice a week helps prevent muscle loss linked with aging. Additionally, since muscle tissues help burn more calories, an increase in muscle mass means losing more weight. A study of healthy men who were around 50 to 65 years old did 3 times of resistance training weekly for 16 weeks and their RMR increased by 7% (16).

3. Incorporating Activities into Your Lifestyle

Walking to the grocery store, instead of driving to it can increase your energy expenditure. By adding oomph to mundane tasks, you get to reduce your fats with minimal effort. Next time you go to work, try using the stairs instead of the elevator.

Both exercise and non-exercise activities contribute to 10 to 30% of burned calories. For really active people, it can contribute to as much as 50% (17).

Other Ways to Boost Metabolism Aside From Physical Activities

If you are not a fan of working out, don’t fret. Here are a couple of ways to keep the weight off and speed up metabolism for quicker weight loss:

1. Consume More Protein

Eating protein helps you feel fuller and reduces the chances of overeating (18). Most people who lose fat also suffer a drop in metabolic rate. By consuming more protein, metabolism can be maintained when dieting (19). 

2. Hydrate

Drinking water can temporarily boost metabolism (20). Studies indicate that consuming 17 ounces of water can boost RMR by 30% for an hour (21).

3. Move or Walk Around

Walk around and stop sitting around all day. It is bad for your health (22). Even if you work in an office, stand up from your chair and walk around. Going for short breaks will help you use up more calories.

4. Drink Tea

Enjoy a cup of green or oolong tea. Both types of tea are known to improve metabolism by around 5% (23). Green tea and oolong tea are both low in calories, so they are ideal for both weight loss and maintenance. They are considered to have metabolism-boosting properties that stimulate weight loss. However, do not assume that taking teas will solve your weight gain issues. Some studies claim that teas have little to no effect on metabolism (24).

5. Eat Spicy Foods

Capsaicin, found in peppers, is known for its effect on metabolism (25). Unfortunately, you will need to consume a huge amount of spicy peppers for you to notice its effect. Not all will be able to tolerate (26). However, adding spices to your cooked meals can give you some advantages when doing other metabolism-boosting methods.

6. Rest and Sleep

Not getting enough sleep has been linked to multiple health diseases. One of them being obesity. Sleep deprivation also affects metabolism (27). Blood sugars are increased leading to insulin resistance. People are prone to develop diabetes and increased body fat with increased insulin resistance. Additionally, lack of sleep causes grehlin, the hunger hormone, to rise. This is the reason why you experience too much hunger when you did not have complete hours of rest.

7. Take A Cup of Coffee

Coffee has caffeine that can improve the metabolic rate by up to 11%. It also contains fat-burning properties like green tea. One study, however, seems to suggest that the improved fat-burning ability is more evident on already lean people. One study showed that coffee improved metabolism by 29% for lean women, while it only helped obese women by 10%. 

8. Use Coconut Oil

Coconut oil is rich in medium-chain fats, which can help boost your metabolism by as much as 12% as compared to long-chain fats present in foods like butter (28). 

9. Add Ginger to Your Drinks or Meals

Adding ginger to your meals can help increase metabolic rate and body temperature. It can also suppress your appetite. A review of studies showed that this spice can reduce fasting glucose levels and body weight while increasing HDL or good cholesterol (29). 

10. Never Starve Yourself

While it is recommended to eat less to lose weight, eating too little is normally counterproductive in the long run. Calorie restriction can decrease your metabolic rate. This effect is known as starvation or metabolic adaptation. Eating less than 1000 calories daily will decrease your metabolic rate and it will stick around even after you stopped dieting (30, 31). 

10. Take B Vitamins

B Vitamins are very important to keep a well-functioning metabolism. They help your body metabolize proteins, carbohydrates, and fats, and to use the stored energy in food. 

11. Munch on Brazil Nuts

Brazil nuts are very rich in Selenium, a mineral that is needed for metabolism, immune function, and reproduction. They are also good sources of proteins and fats that may help increase feelings of fullness. Each piece of Brazil nut contains 68 to 91 micrograms of Selenium, an amount that is way more than the recommended daily allowance of 55 mcg (32). However, you should not take more than 400 mcg daily to avoid toxicity. 

12. Cook Broccoli

Broccoli is known to benefit metabolism due to its high glucoraphanin content. Glucoraphanin can retune metabolism, decrease blood fat levels, and reduce the risk of several age-related diseases and some types of cancer. 

Key Takeaway

Basal metabolic rate is something that is out of your hands, but there are many ways to burn calories. Slow metabolism is a contributor to weight gain, but it is not everything. Eating a healthy diet, exercising regularly, and practicing metabolism-boosting strategies can help you keep the weight off. 

References

  1. https://www.britannica.com/science/metabolism
  2. https://opentextbc.ca/anatomyandphysiology/chapter/24-1-overview-of-metabolic-reactions/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4272668/
  4. https://www.ncbi.nlm.nih.gov/pubmed/11101268
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276215/
  6. https://www.ncbi.nlm.nih.gov/pubmed/10749826
  7. https://www.sciencedaily.com/releases/2019/07/190715164655.htm
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818133/
  9. https://www.ncbi.nlm.nih.gov/pubmed/24261006
  10. https://www.ncbi.nlm.nih.gov/pubmed/8644681
  11. https://www.ncbi.nlm.nih.gov/pubmed/21576503
  12. https://www.ncbi.nlm.nih.gov/pubmed/21576503
  13. https://www.ncbi.nlm.nih.gov/pubmed/8386182
  14. https://www.ncbi.nlm.nih.gov/pubmed/20627487
  15. https://www.ncbi.nlm.nih.gov/pubmed/22434603
  16. https://www.ncbi.nlm.nih.gov/pubmed/8175496
  17. https://www.ncbi.nlm.nih.gov/books/NBK279077/
  18. https://www.ncbi.nlm.nih.gov/pubmed/16400055/
  19. https://www.ncbi.nlm.nih.gov/pubmed/23097268
  20. https://www.ncbi.nlm.nih.gov/pubmed/24179891
  21. https://www.ncbi.nlm.nih.gov/pubmed/21750519
  22. https://www.ncbi.nlm.nih.gov/pubmed/25599350
  23. https://www.ncbi.nlm.nih.gov/pubmed/20142827
  24. https://www.ncbi.nlm.nih.gov/pubmed/23235664
  25. https://www.ncbi.nlm.nih.gov/pubmed/16580033
  26. https://www.ncbi.nlm.nih.gov/pubmed/16840650
  27. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929498/
  28. https://www.ncbi.nlm.nih.gov/pubmed/3532757
  29. https://www.ncbi.nlm.nih.gov/pubmed/29393665
  30. https://www.ncbi.nlm.nih.gov/pubmed/26399868
  31. https://www.ncbi.nlm.nih.gov/pubmed/19198647
  32. https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
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