[Sports Nutrition] Metabolism: The Role of Exercise and Diet

May 19, 2022

What is metabolism?

Metabolism is the vital process by which our bodies burns energy from foods (i.e. catabolism) for survival, maintenance, and growth (i.e. anabolism).Our total energy expenditure can be divided into three components:

  • Basal metabolic rate (about 50-80%of total energy expenditure). This portion of energy is used for maintaining vital functions of our body, for example, breathing, heart beating, cell growth and repair.
  • Thermic effect of food (about 5-10% of total energy expenditure). This portion of energy is used to digest, absorb, transport and store all foods and beverages we consume.
  • Energy used during exercise varies depending on how much you work out on a daily basis.

Can metabolism be boosted?

The rate of metabolism varies among individuals and is dependent on many factors including genetics, age, gender, hormonal homeostasis, and even environmental temperature, etc. Whilst some of these factors are predetermined, we can increase our metabolic rate by building muscle mass via exercise.

How does exercise influence metabolism?

Studies have demonstrated that regular exercise exerts a myriad of metabolic benefits:

  • Increase muscle mass which burns more calories faster as compared to fats
  • Increase blood flow and microvascular units, hence, promote a higher supply of nutrient/energy to peripheral organs such as the heart, liver, pancreas, muscle tissues and fat tissues
  • Promote the trafficking of dietary fatty acids from storage to oxidation (i.e. burning)
  • Promote glucose utilization from glycogen storage in the liver
  • Increase insulin sensitivity hence blood glucose regulation

“The World Health Organization recommends all healthy adults to exercise for at least 150 minutes (moderate intensity) or 75 minutes (vigorous intensity) every week.”

How does nutrition come into play?

  1. Forget about magic “fat-burning” diet or food. While some studies have discovered temporary metabolic increase after consumption of food items such as green tea and hot chilies, the effects were not significant nor sustainable to result in any notable changes in body weight or parameters of metabolic health. Instead, aim to build your diet around a variety of nutrient-dense foods and avoid energy-dense counterparts which often offers less nutritional values. 
  2. Avoid crash dieting or unsupervised fasting. Extreme caloric reduction may not only slow down metabolic as your body attempts to reserve energy, it may also lead to muscle loss, malnutrition, fatigue, hair loss, sleep disturbance, and other health impacts. It is strongly advised to consult your Registered Dietitian for pre-assessment and monitoring shall you wish to implement any fasting regimes.
  3. Treat your gut microbiota well. The trillions of microorganisms living in the gut helps break down complex carbohydrates, proteins and some fats into smaller bits that our body can utilize. Help your tiny buddies thrive by feeding them (and yourself) prebiotics (e.g. wholegrains, fruits and vegetables) and probiotics (yogurt, miso, kimchi, kombucha)!
  4. Make sure you fuel right before, during and after exercise.

Ref: Better Health Channel, Academy of Nutrition and Dietetics, Thyfault JP, et al. Diabetologia