What is metabolic flexibility?

Metabolic flexibility is the ability to respond or adapt to conditional changes in metabolic demand. In common terms, it’s the ability to access or tap into different fuel sources efficiently and effectively.

What fuel sources? Glucose and fat (ketones). Most people today run primarily off of glucose, it’s the quickest energy source for our body to access. But there are limitations on the amount of glucose accessible to the body because you only store about 2000 calories of glycogen. When the body has run out of glycogen stores, it will turn to burning fat for fuel in the form of ketones. This is part of why so many people have begun following a ketogenic diet. The average person has a good reserve of fat that can be burned for fuel, over 30,000 calories for the average person.

When the body needs energy, it’s going to choose the path of least resistance, and this will be glucose. Until the body becomes more “fat adapted”, it will seek out glucose for energy until it learns that it can also access fat stores for fuel.

Metabolic flexibility is the ability for the body to switch between these two fuel sources depending on what the body is needing at that time. The body then learns to not depend on just one pathway for creating energy, and this level of flexibility means that the body is able to adapt quickly to changes in metabolic needs.

Being metabolically flexible is beneficial for:

  • remaining insulin sensitive
  • fighting type II diabetes
  • weight-loss
  • autophagy
  • fighting oxidative stress
  • fighting the aging process
  • and more

Signs that you are not metabolically flexible:

  • Hungry within 2 hours of eating
  • Energy is not steady throughout the day
  • Cravings for sugar and carbohydrates
  • Weight-loss resistant
  • Relying on caffeine to get going
  • Getting tired after a meal with carbohydrates
  • Fasting for any length of time is difficult

How to become metabolically flexible.

  1. Decrease carbohydrate intake – In order for the body to switch to burning fat/ketones for fuel, it has to deplete its glycogen stores first. The body will always burn glucose first because it is the quickest and easiest fuel source. Where does glucose come from? Carbohydrates! Therefore reducing (not eliminating) carbohydrates will help to train the body to look for an alternative fuel source – fat. 

Following a ketogenic diet may be therapeutically beneficial for a short amount of time to help train the body, however, this way of eating is not necessary and might not be right for you. So please consult with a functional practitioner or nutritionist, such as myself, before attempting any of these changes. Most people do not need to go to the extreme of a ketogenic diet to get these benefits, and the goal is to keep the body efficient at using carbohydrates for fuel too, so cutting them out completely is not the end goal.

  1. Increase fat intake – Eating fat helps train your body to burn fat. Most people think that eating fat will make them fat, however, this is one of the biggest nutritional fallacies out there. Eating unhealthy, processed fats most certainly can lead to fat accumulation, but eating whole food versions of fat such as avocados, coconut oils, nuts, seeds, and olive oil are beneficial in weight management.
  1. Intermittent Fasting – Almost everyone has now at least heard of intermittent fasting or time restricted eating. Intermittent Fasting (IF) is less about what you eat, and all about when you eat. You can read more about fasting on this blog I did. The reason that IF can help with metabolic flexibility is because during those longer fasting windows, it gives the body time to burn and utilize glucose, and then move on to burning fat for fuel. This is my preferred way to train my body to be metabolically flexible and most of my clients have found this to be the best way for them as well.

Please note that intermittent fasting IS NOT for everyone. There are actually quite a few people that should not intermittent fast because it can make them feel worse. Please read more blog for more information on that. I truly think that everyone needs to have at minimum their hormones testing prior to intermittent fasting because if there are underlying hormonal imbalances, intermittent fasting can make these worse. So please, before attempting, jump on a quick call with me so that we can decide if intermittent fasting is safe for you.

  1. Fasted Cardio – This is when you workout prior to consuming anything to eat. Again, this works because the body is forced to searching for fat to burn as fuel, especially if you are working out first thing in the morning after having slept and fasting for at least 8-10 hours. The body will burn through any excess glucose within the first 20 minutes of the workout, and then will begin to burn fat, therefore, fasted workouts should be at least 40 minutes in length.

Fasted cardio tends to be a safe option for most people. However, if you have blood sugar imbalances, extreme hormone imbalances, or HPA-axis dysfunction, fasted cardio might make you feel more lightheaded or fatigued, so please consult with a practitioner before attempting.

If you are struggling with being metabolically flexible, and you’d like to support your body in becoming more adapted, schedule a complimentary consultation with me today. Keeping the body in a state of flexibility is a strong indicator for overall health and longevity.

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