Metabolic Flexibility: Two Tools for Robust a Robust Metabolism 3/5 in the series
The Metabolism Train is well on its way!
You’ve landed on the third chapter of the series. Catch up on all the others here:
Metabolic Health: an Intro
2. Taming the Blood Sugar Roller Coaster
3. Saboteurs and Saviors: how to help and how to hurt your Metabolism
5. A Metabolic Conversation with Special Guest
We’ve covered what numbers to track and we talked about “thoughtful carbing.”
With only that information you are armed to make real change. But I want the best for you! I’ve given you the tools to trouble shoot and regulate, now let’s delve into optimization with a concept called metabolic flexibility.
Metabolic Flexibility = Multiple Fuel Options
With the price of gas, who hasn’t wished their car ran on something else? Don’t get to smug, my Tesla owning friends, I’ve seen you run out of charge too! The best car we ever owned was a hybrid. It could run on electric or gas, which gave us peace of mind because we were less likely to get stranded anywhere. Good news for you folks: our bodies are hybrids! They are built to run on multiple fuel sources.
We mentioned last week that carbs are the primary fuel of our body. Carbohydrates break down quickly, and with the modern abundance of carbs, we’ve been conditioned to burn them easily. A system the runs predominantly on carbs can atrophy in its ability to burn other fuels.
What are these other fuels? Meet your macronutrients, our good buddies Carbs, Proteins & Fats. These components make up all the food—all the energy sources—our metabolism will encounter.
Meet your Macros:
Example of a carb heavy meal. Tasty, but it burns (or stores) fast!
Carbohydrates
4 calories per gram. Burn fast and dirty through a process called glycolysis. Readily available and its end product is glucose.
Protein
4 calories per gram. Protein is not an efficient fuel. It is broken down into amino acids and used as building blocks for the body. In some cases, it can be broken down to create glucose in small amounts. For the purpose of this discussion, let’s think of it as building blocks rather than fuel.
Fat
9 calories per gram. Right out the gate we see that fat is a denser energy source than the other 2 macros. That’s not all that’s special about fat. Besides it’s nutrient impact on the body, it has a metabolic superpower: it can be burned for energy and not only produces fewer metabolic waste products than carbs do, but fat burns without impacting blood sugar (so no spikes and crashes!) and burns longer.
If you’re used to burning diesel, the price and cleanliness of an electric car might really appeal, especially when the gas light comes on and you’re breathing fumes! If you understand fat as a fuel source, you may feel the same allure. But if you are driving a gas-powered vehicle, how do you convert to hybrid energy? In other words, how can you rev up your body’s fat burning abilities so you have a flexible and efficient metabolism?
Two Flexibility Strategies
Intermittent Fasting and the Ketogenic Diet. There are legions of books on both of these (I know, I own shelves of them!) and I can only give brief overviews here. But keep an open mind as you look at these as tools. Consider what they may have to offer you as we continue!
Intermittent Fasting (IF)
IF is a dietary strategy that involves cycling periods of eating and fasting.
This food timing practice increases metabolic health by giving your digestion a rest and encouraging your body to clean house. Intermittent fasting has been associated with weight loss, improved blood sugar regulation, and reduced inflammation.
There are various ways to practice intermittent fasting, such as the 16/8 method, which involves fasting for 16 hours and eating within an 8-hour window, or the 5:2 diet, which involves eating normally for five days and restricting calorie intake for two days.
It’s not as hard as it might sound: you are already fasting at night from the last bite you take in the evening to the first bite you take the next morning at break-fast. With intermittent fasting, you simply stretch that window.
If I stop eating after 6pm and start again at 10 am—I just did a 16 hour fast, long enough to reap these benefits!
Keto
The ketogenic diet is a diet very low in carbs and high in fat that forces your body to flex another metabolic muscle called ketosis.
In a state of ketosis, the liver converts fat into ketone bodies. Ketones can be used as a fuel source by the brain and other tissues in the absence of glucose.
It’s important even in a brief description to dispel the myth that keto is all bacon and butter. A nutritional or clean keto diet looks very different from the fad keto foods you might see on social media or Walmart shelves. A healthy keto diet is actually high in healthy non-starchy vegetables. Just make sure there’s plenty of healthy salad dressing on those greens and browned butter on your broccoli (yum)!
Intermittent fasting and ketogenic diet are both dietary strategies that help build metabolic flexibility in several ways:
Increases fat utilization: Both diets promote an increase in fat utilization for energy production. This means that the body becomes better at burning fat as fuel, which helps improve metabolic flexibility and insulin sensitivity.
Improves mitochondrial function: Keto and I.F. have been shown to improve mitochondrial function - the powerhouse of cells - which is responsible for producing ATP, the body's primary source of energy.
Reduces inflammation: Both have been shown to reduce inflammation in the body, which is important for metabolic health. Inflammation is linked to insulin resistance, which can negatively impact metabolic flexibility.
Promotes autophagy: Intermittent fasting is known to promote autophagy, a process by which the body breaks down and recycles damaged cells and cellular components. This process helps improve metabolic flexibility by renewing the body's cellular machinery, leading to increased energy production.
Lowers glucose & insulin levels: Both diets have been shown to lower blood glucose and insulin levels, which helps improve insulin sensitivity and metabolic flexibility. This can help the body efficiently switch between using glucose and fat as fuel sources.
Anyone can harness the benefits of these two strategies.
Fasting can be used on occasion or regularly as a metabolic exercise. Many people choose to do it daily, others more sporadically. I generally fast 16 hours most days and an extended 24 hour fast once a month. (hint: if you’re metabolically flexible, fasting is easy. If you aren’t, it can require some help and patience to adapt.)
Keto is a metabolic state and can’t be used quite as intermittently. If you’ve never done the ketogenic diet, it can take as long as 6 weeks of strict adherence to get proficient at producing ketones! But it may be worth the effort to open that pathway.
Once established, your body can go in and out of ketosis easily.
For example, I feel and function better in ketosis so it’s my default but I’ll cycle out for holidays, travel or big events (like my beloved peach season!) My friend and fellow nutrition therapist, Bev, prefers to live on smart cabs but is experimenting with adding keto to her routine.
There is a misconception that once you go keto, you’re keto for life. The point of flexibility is to be able to use both glucose AND fat as fuels. Keto may be a tool you want in your box so you have the most control over your metabolism and can adjust. If your blood sugar numbers begin to rise, it may be time for a month of keto. If your sweet tooth is starting to take over, a week or two in ketosis might just re-calibrate it for you.
Intermittent Fasting and Ketogenic diets are tools we nutrition therapists use regularly with clients for a host of ailments. If metabolic dysfunction is starting to impact your quality of life, there’s a high chance these practices can turn it around for you.
Reach out if you’re interested in learning how to incorporate either or both into your own personal plan! There’s not much I get more excited about.
If you are ready to jump into the action phase of your metabolic health, read about my 30 Day Metabolic Reset Program. It is a real time experiment you embark on to learn all about your own unique biology and find out exactly how to understand your own metabolism.
