Blog | Metabolic Flexibility- the Key to Fat Burning and Sustained Energy

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Metabolic Flexibility- the Key to Fat Burning and Sustained Energy

BySarah Axtell, ND April 29, 2021

If you feel like you are a slave to food you may be metabolically inflexible. Your body may be so dependent on getting fuel and energy from carbs that you constantly feel the need to snack. If you can’t go longer than 4 hours without food, it’s time to focus on achieving metabolic flexibility so you can achieve a healthy weight AND feel good. Say “goodbye” to constantly seeking food!

What is Metabolic Flexibility?

Metabolic flexibility is the ability to switch between obtaining fuel from carbs or fats (dietary fats or stored fat in your body) based on what’s available. Your body’s ability to switch between using different fuel sources results in a more efficient fat-burning state and more sustained energy.

Humans evolved in environments where food was often scarce, and therefore we developed many adaptations that enabled us to function at a high level, both physically and cognitively, when in a food-deprived or fasted state. In pre-industrial times, some days there was plenty of food and some days there was no food at all. Metabolic flexibility allowed us to go days without eating and still function at a high level by obtaining fuel from fat stores (fat oxidation). Metabolic inflexibility is a modern malady linked to obesity, insulin resistance, fatigue, and inflammation.

Signs of Metabolic Inflexibility:

  • Inability to go more than 4 hours without food
  • Feeling “hangry”- irritable or shaky in between meals
  • Fatigue, especially post-meals
  • Carb and sugar cravings
  • Inability to exercise in a fasted state
  • Inability to lose weight
  • Brain fog

How Do I Achieve Metabolic Flexibility?

  1. Intermittent Fasting.

When you eat a meal you are in a fed state, or absorptive state, for 3-5 hours in which your body is working hard to digest and absorb food. During this fed state (high insulin state), it is difficult for your body to burn fat because insulin is ever-so-present. Insulin is the hormonal signal to the body to make and store fat.

But after the 3-5 hours in the fed state, your body enters the post-absorptive state, or fasting state (low insulin state). This state lasts 8-12 hours after a meal, and it is much easier for your body to burn fat because blood sugar and thus insulin has decreased. So if you are grazing and eating every 2 hours, you are constantly in a fed state and can never metabolically shift into the fat-burning state. But intermittent fasting is an approach that can promote this metabolic shift.

Aim for a 12-16 hour overnight fast and avoid snacking.

2. Eat a Diet Higher in Protein and Fat and Lower in Carbs.

When we a carb heavy diet, we are programmed to extract energy only from carbs, which are a “dirty” burning fuel. That roller-coaster ride that you constantly feel like are you are on is due to the sugar and carbs in your diet and the resulting inflexibility of your metabolism. You should not need to nap after eating. You should not feel hungry 2 hours after eating. If this is the case, you are likely relying solely on carbs as your fuel source.

You can program your body to be more metabolically flexible by eating a lower-carb, higher-fat, higher-protein diet. Dietary fat is an efficient “clean” fuel source for your body as compared to carbs.

Foods to incorporate to promote metabolic flexibility:

  • Nuts and seeds
  • Lean proteins, such as fish, chicken, and turkey
  • Eggs
  • Green leafy vegetables
  • Crucifeorus vegetables
  • Avocados and avocado oil
  • Olives and olive oil
  • Berries

Foods to avoid to promote metabolic flexibility:

  • Breads and pasta (even ones labeled “multi-grain,” “whole grain,” or “gluten-free”)
  • Pretzels, cereals, crackers, cookies, granola, granola bars
  • Flour
  • Sweets and treats- cookies, candy, ice cream

3. Avoid Endocrine Disrupting Chemicals In Your Environment (“Obesogens”)

Obesogens are a sub-class of endocrine disruptive compounds that interfere with a healthy metabolism. This means that your laundry detergent and plastic water bottles may be wreaking havoc on your metabolism and leading to weight gain. Here are some examples:

  • Bisphenols- You’ve heard of BPA, commonly found in plastics. But BPS and BPF are other bisphenols that are still likely lurking in your “BPA-free” plastic containers and water bottles that have similar adverse effects on your hormones and metabolism. Avoid plastics whenever possible, even if they are labeled “BPA-free.”
  • Phthalates– found in toys, flooring, mattress covers, vinyl shower curtains, detergents, and plastic food containers.
  • PCBs- found in fatty meats and dairy products
  • Glyphosate- found in commercial foods. The most common crops exposed to glyphosate include wheat, barley, oats, chickpeas, soy, and canola.

4. Fasted Exercise.

It has long been established that metabolism is modified by physical activity. Varying the type of exercise you do (strength training, high intensity interval training, walking, yoga) is beneficial for your metabolism.

Timing of exercise in relationship to a meal also has a great impact. Fasted cardio is one way to tap into your fat stores. Aim to eat a protein-rich meal 30-60 minutes AFTER you workout. A smoothie with plant-based protein powder is my favorite post-exercise meal.

If you feel like you are metabolically inflexible, we are here to help. Achieving metabolic flexibility truly is liberating!

Editor’s Note: The information in this article is intended for your educational use only. Always seek the advice of your physician or other qualified health practitioners with any questions you may have regarding a medical condition and before undertaking any diet, supplement, fitness, or other health program.


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