Metabolism is a tricky topic. Every day, whether I’m seeing clients at FFC, talking to friends or getting served a targeted Instagram post, I hear/see the words metabolism or hormones. It’s hard to pinpoint exactly how each individual person’s metabolism works, and in the field of nutrition, research is always ongoing. 

Metabolism is complex and various factors impact it. While we can’t control all factors that impact our metabolism, we may be able to address some and ultimately optimize the way our metabolism works through nutrition, lifestyle and physical activity. 

What Is Metabolism?

Metabolism refers to how your body stores and uses energy from food. It’s how your body works to break down nutrients into their simplest form for transport into cells. 

Here’s a quick breakdown of the function of how your body utilizes (or metabolizes) energy: 

  1. The body breaks down macronutrients into their simplest form for transport to your cells

Carbohydrates →  glucose

Protein → amino acids

Fat → fatty acids

  1. Growth and maintenance of muscle
  2. Break down of fat stored in the body

Factors That Impact Your Metabolism

When it comes to factors that have the biggest impact on our metabolism, it really boils down to three things: 

  • Metabolic Rate
  • Hormones
  • Nutrients

Metabolic Rate

Metabolic Rate refers to the total amount of energy expended each day and is determined by three main components: 

  • Basal metabolic rate (BMR)
    • The amount of energy we use at rest. Although it may not seem like you’re doing any active work, your body is working hard to keep the heart pumping, build and repair cells and make sure all the organs are functioning properly. BMR actually accounts for about 50 – 80% of our daily energy expenditure.
    • So, what determines BMR? It can be influenced by a combination of genetics, body size, lean muscle mass, age, gender, hormonal balance, environmental temperature, how we eat and drug use. 
  • Thermic effect of food
    • The energy used by the body to digest, absorb, transport and store nutrients.
  • Physical activity
    • Energy used during physical movement
    • Varies depending on how much energy is used each day

Related: My Resting Metabolic Rate Test Experience And What I Learned


Metabolic functions are controlled by hormones. Hormones control: 

  • Hunger
  • Motivation
  • Focus
  • Well-being
  • Fat and muscle storage and breakdown 

The key is to strike the right balance of hormones, otherwise, regular metabolic functions can be disrupted. Some common hormones that impact our metabolism are thyroid hormones, ghrelin, leptin, testosterone, estrogen, human growth hormone, insulin, and cortisol.


Outside of energy in, energy out, what you eat and how much you eat may impact your metabolism. Different nutrients may impact the hormones that dictate how your metabolism runs. 

The following are macronutrients and foods that may impact your metabolic hormones: 

  • Sugar: excess amounts can cause deregulation of metabolism and sex hormones
  • Fiber: regulates blood sugar and helps avoid hunger
  • Omega-3 fatty acids: act as metabolic messengers that signal use of fat for energy
  • Protein: decreases sensations of hunger, improves energy and limits cravings
  • Water: helps control hunger by creating sensation of fullness
  • Tea: may have fat-burning effects; can help reduce stress and relax nervous system
  • Coffee: can increase stress hormones and increase blood sugars
  • Sweeteners: may increase hunger, causing release of fat-storing hormones
  • Cacao (100%): can help with feelings of satisfaction, motivation and provide energy
  • Alcohol: can slow down metabolism of fat and cause dehydration

Related: How To Enhance Your Longevity Through Nutrition

Micronutrients that are involved in making your metabolism work at its optimal level are: 

  • B Vitamins: essential for energy metabolism (FOOD SOURCES: meat, seafood, eggs, poultry, legumes, milk, leafy green vegetables)
  • Vitamin D: may help control blood sugar (FOOD SOURCES: salmon, mackerel, egg yolks, beef, liver, fortified milk, some mushrooms) 
  • Calcium: may help control blood sugar (FOOD SOURCES: dairy products, yogurt, sardines, beans and lentils, leafy green vegetables)
  • Iron: vital for cell functioning and hormone production (FOOD SOURCES: meat, beans, fortified cereals, brown rice, nuts, tofu, leafy green vegetables) 
  • Magnesium: needed for chemical reactions that produce energy (FOOD SOURCES: nuts, seeds, legumes, spinach, bananas, whole grains, potatoes) 

Optimizing Your Metabolism Through Nutrition And Lifestyle

While there are many things you can do to help regulate and balance out your hormones so that your body’s metabolism can run as smoothly as possible, here are my top 6 to get started:

  • Watch the amount of starchy/sugary foods at meals to ensure blood sugar is regulated and doesn’t cause an imbalance of other metabolic hormones
  • Eat healthy fats to support fat metabolism
  • Eat lean protein or plant-based protein 
  • Try weight training and high intensity interval training workouts to help with fat metabolism 
  • Get 7 – 9 hours of sleep – this allows the body to rest, regenerate and reset hormonal balance
  • De-stress – stress can increase energy metabolism but too much stress can stimulate increase of cortisol, and excess cortisol can suppress testosterone, which may cause a decrease in muscle mass and metabolism and lead to extended insulin release and increased fat storage 

Here’s Where To Start

That was a lot of information, I know, but metabolism is really complex. If you feel like your metabolism has changed or you are simply looking for where to start, the first thing I recommend is making sure you are feeding your needs. So if you’re working out, that means making sure you’re eating enough to support those workouts and daily activities.

The best way to figure out how much energy you need is through indirect calorimetry – which is a method used to measure how your body is converting oxygen to carbon dioxide (aka – how your body is metabolizing energy). It’s used to measure your energy expenditure (or, calories “burned”). If you want to know more about how to do this, FFC offers a Resting Metabolic Rate Test. Once we figure out the current state of your metabolic rate, we can talk about what you’ve been doing in terms of lifestyle, physical activity and nutrition that may be impacting your energy expenditure and metabolic hormones.

The process is ongoing, but taking metabolism from all angles, bit by bit, can help optimize it for your needs.

Post written by FFC Registered Dietitian Kathy Chung.