The Role of Metabolism

Holistic Nutritionist and Personal Trainer -

The Role of Metabolism

What is it?

The term "metabolism" can feel like a loaded one that can be confusing to the average joe who's just trying to live a healthy lifestyle. Put simply, metabolism refers to all the chemical processes your body uses to produce energy. Your body converts food to energy to carry out the every day functions it needs to maintain itself.

Factors Which Affect Metabolism 

  • Age
  • Weight
  • Physical activity
  • Medication
  • Genetic factors

Role of Food in Metabolism

Food provides critical nutrients for a healthy metabolism. For a person's metabolism to function effectively, we must give our bodies enough vitamins, minerals, essential amino acids, and essential fatty acids—which must be ingested from an outside source. This means that our food choices have a huge impact on how well our bodies function.

Increasing Metabolism

Do some people have a faster metabolism than others? Yes. The rate of a person's metabolism depends on several factors, including the quality and amount of food they consume as well as their physical activity level.

Incorporating a mixture of healthy foods and and plenty of exercise can help increase the metabolic rate of an individual. However, because muscle cells require more energy than fat cells, those with more muscle tend to have a higher metabolic rate. Also, when examining the difference between men and women, men tend to have more muscle mass, heavier bones, and less body fat—and therefore their daily calories requirement and metabolic rate tend to be higher. The average man requires approximately 2,500 kcal a day, whereas for an average woman requires about 2,000 kcal a day.

The Thermic Effect of Food (TEF)

Macronutrients (proteins, carbs, fats) each have a unique effect on the body’s metabolism due to each having their own level of ‘difficulty’ when being broken down and digested. Our caveman ancestors would have had more hurdles to jump through here, having consumed most of their food raw, but modern-day food prep methods allow us to almost ‘pre-digest’ foods by breaking them down and making them easier to digest. These methods include cooking, steaming, or even curing (think about how raw fish can be almost cooked when exposed to natural chemicals like acidic lemon juice).

So, what is “TEF”? In short, it's best described as: “The amount of energy required to digest and process the food you eat."

What this means on paper is that for every 100 calories of any given macronutrient, you will only be left with a percentage of that initial 100 for bodily functions due to some calories being used to breakdown/transport/use of the individual macronutrient.

The (generally accepted) TEF for the following macronutrients are:

  • Carbohydrates = 12% (5-15%) TEF
  • Protein = 20% (20-35%) TEF
  • Fats = 3% (0-5%) TEF

Remember, foods with minimal processing tend to have the highest thermal effect. This also applies to proteins, carbohydrates and fats. Hence, you should prioritize these in your diet to maximize TEF.

You can increase your daily TEF by eating more protein and whole foods, but not increasing the frequency or size of your meals (eating more often will not “get your metabolism going”).

Additionally, there is good evidence that strength training can also increase the thermal effects of foods. But we'll get into that in another blog!

Warren Dias is an international men's physique athlete, certified personal trainer, and nutritionist with the goal of motivating and inspiring people to achieve their fitness goals through his years of knowledge and experience.