Metabolic fitness, or metabolic flexibility is the ability to burn fat and sugar for fuel efficiently, effectively, and appropriately. For example, when I exercise, I want to be good at burning sugar for fuel and producing energy without oxygen; and when I'm at rest, I want to be good at burning fat for fuel and conserving sugar. Most people (estimated 88% of the population) are stuck in sugar burning mode due to high levels of the hormone, insulin.
Insulin is an incredible hormone, it helps keep blood sugar in check. Its primary job is to take sugar out of the bloodstream and into the cells so it can be used as fuel. This is protective for the body, as chronic high blood sugar can cause a variety of serious issues, from neuropathy to heart disease. Too much insulin - from a high carb diet, grazing all day, or an unfavorable BMI - can make it very difficult to burn fat for fuel. This is often why the equation of (low calorie diet + exercise = no progress) is often the end result when insulin is elevated and the body is metabolically inflexible. If this is you, don't fret, there are some very simple and cost effective ways to bring insulin down with diet and lifestyle strategies.
How does one become more metabolically fit?
To become metabolically fit or flexible, it's important to address insulin through a variety of hormone balancing principles:
1) Intermittent Fasting: is found to be effective in diabetic and pre-diabetic individuals by lowering the fasting blood glucose by almost 4mg/dL. There are many ways to structure a fasting window, or period of time to feed vs fast. For beginners, rather than eat 5-6 meals or graze all day like many of us have been taught, try eating 3 meals per day within a 10 hour eating window. This practice will encourage mindful eating, lower insulin levels, and it's a pretty easy timeframe to fit into any lifestyle.
2) Hydration: this is an overlooked piece of the puzzle when it comes to hunger and satiety - and when appetite hormones are off, the chances of sticking to any "diet" are slim to none. The hunger hormone, ghrelin, is released by the stomach when it is empty, or when it has been conditioned to do so. For example, if I wake up and eat a big bowl of cereal everyday at 7 am, my body is going to feel hungry at 7 am because that's what it's used to. To suppress ghrelin, try drinking a big glass of water upon waking, the distention will curb that 7 am craving, and hydrate throughout the day to keep this hunger hormone in check.
3) Low Carb Diet - Multiple studies show the ketogenic diet’s ability to lower insulin levels, reduce inflammation, and improve insulin receptor site sensitivity, which helps the body function optimally. Research has revealed that symptoms of type 2 diabetes can even be reversed after just 10 weeks on a ketogenic diet! In my practice, I have witnessed women with weight loss resistance shed almost 100 lbs, and people reverse their diabetes - with diet only! Food is such a powerful tool.
How does this work? The ketogenic diet transitions the body from sugar burning to fat burning mode, so the body no longer needs to rely on glucose for energy. Instead, the energy comes from ketones, which are the by-products of fat burning. Ketones are not only a more sustainable form of fuel for your body, but they keep blood sugar more stable than a diet fueled by low-fat, high-carb foods, ie grains, high fructose fruits and sugar.
When approaching a low carb lifestyle, it's important to take into account your carb threshold, which is influenced by a variety of factors. I recommend working with a dietitian/nutritionist who is experienced in ketogenic diets for the most safe and effective results.
4) Exercise - Exercise helps maintain healthy blood sugar levels by increasing insulin sensitivity and making your muscles more efficient at glucose absorption. Studies suggest high-intensity interval training is the most effective at burning sugar, but any form of cardio that you can maintain over the long haul, along with some resistance training, is an excellent and sustainable approach.
Yoga and Pilates have a good mix of strength, cardio and relaxation and have been researched
for their positive impact on stabilizing blood sugar in diabetes patients.
Taking a walk around the block after dinner each night is an excellent habit which allows your
body to burn off some glucose so that you sleep better-and as controversial as it may be in
some families, being the one who does the dishes and tidies up before bed can be just as
5) Sleep Hygiene - insufficient sleep can dramatically impact energy levels, cravings, and hormones throughout the day which make it extremely challenging to stick to intermittent fasting and a low(er) carb lifestyle. Aim to get at least one hour of sleep before midnight. Ideally two if possible. Every hour of sleep before midnight is equivalent to three hours of the regenerative capacity of sleep after midnight.
If getting to bed by 10 pm is a struggle, there are several things you can you incorporate into your evening:
- Set an electronics curfew by 9:30 pm.
- Try blue light blocking glasses.
- Rise with the sun and wind down at darkness.
- Don't be productive after 9 pm. Completing tasks and goals after 9 pm can release catecholamines which give the feeling of a second wind, and suppress melatonin.
6) Stress Management - Stress increases the hormone cortisol. When cortisol floods the body, blood sugar increases and the pancreas is triggered to produce insulin which quickly brings your blood sugar down, triggering hunger and snack cravings. Stress can be perceived or physical, but either way - high stress leads = high amounts of cortisol. Here are ways to reduce stress:
Exercise, but avoid overexercising
Connect with loved ones
Take a warm bath
Incorporate breath work
Get adequate sleep
If you’re interested in a program that provides you 1:1 accountability, ongoing support, supplement advice, and behavior change, consider getting started with Functional Nutrition of Wisconsin. We are currently accepting new clients. To learn more, book a free Discovery Call here.
In good health,
Kristie + Rebecca
1. Cho Y, Hong N, Kim KW, Cho SJ, Lee M, Lee YH, Lee YH, Kang ES, Cha BS, Lee BW. The Effectiveness of Intermittent Fasting to Reduce Body Mass Index and Glucose Metabolism: A Systematic Review and Meta-Analysis. J Clin Med. 2019 Oct 9;8(10):1645. doi: 10.3390/jcm8101645. PMID: 31601019; PMCID: PMC6832593.
2. Adams OP. The impact of brief high-intensity exercise on blood glucose levels.Diabetes Metab Syndr Obes. 2013;6:113-122.doi:10.2147/DMSO.S29222
3. Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement.Diabetes Care.