What is Metabolic Efficiency and Do I Want It After 50?

What is Metabolic Efficiency, and What Does It Mean For My Health and Wellness?

“Efficiency” is usually thought of as doing something well with the least amount of effort.

Metabolic efficiency is basically this: use more fat for energy while using less carbohydrate for energy and you will ultimately have less fat on your body.

Metabolic efficiency means different things to different people:

If you’re a midlife woman it means using the fat you’ve stored instead of the carbs that you ate last night. That means reducing body fat and increasing your lean look while reducing risk of disease and taking weight off your frame.

If you’re an endurance athlete metabolic efficiency is important to you because it decreases your need to ingest food during events, which in turn decreases the chance you’ll get gastro-intestinal (GI) disturbances that can mean bloating, diarrhea, impaired performance, or “bonking.” I, for example, hung over the handlebars of my bike and lost my cookies in the last triathlon I did. It was not the cover-image of the svelte triathlete I had in my head.

So, you’re not an elite athlete (nor am I). Maybe your not even an exercise enthusiast. As a midlife woman running a home, business, and hormone-driven bus you don’t want to bonk either.

One fat-burning enzyme burns a little fat; a bunch of fat-burning enzymes ignites a bonfire. Metabolic efficiency training builds a stockpile of fat-burning enzymes.

What metabolic efficiency isn’t

Metabolic Efficiency (ME) eating is not a calorie-deficient diet and it is not a low-carbohydrate, Atkins-like diet. It is rather macronutrient partitioning – or manipulating your macronutrients (carbohydrates, fats and proteins) – AND exercise adaptation – or manipulating your exercise with correct aerobic training – that allows us to reap the benefits of increased fat utilization.

To reach metabolic efficiency you must manipulate both diet and exercise together. It takes several months to fully flip the switch. Unfortunately, most of us in search of immediate gratification are more inclined to try something like intermittent fasting. More on that below. [do you really think that intermittent fasting for three days only to return to wine, pizza, and lettuce salad is going to create a lean body that craves healthy food so you’ll stay lean will work?]

But then we’re just reverting to the diet-til-Saturday when the big event is so you can get into the dress. The event gets over and you realize that if you didn’t decide that YOU were worth it without the event, when life is the normal crazy, there have been no habit changes, no mindset shift to make it permanent.

Metabolic Efficiency is about crossover

The crossover concept describes the relationship between exercise intensity and the use of fat and carbohydrate for energy during that exercise. Even though we burn a mix of both carbohydrate and fat to fuel exercise up to maximal intensities, as the intensity of your exercise increases, your body prefers to use more carbohydrate for fuel.

That means and always has, that if you’re sitting reading this you’re burning 100% fat. If you take a long slow stroll around the block you’re burning a bit less but still probably over 80% fat to fuel that. When you do interval training at a level that is associated with greater fat burning after the exercise, you’re burning mostly carbohydrate to actually do the interval. At least, until you teach your body not to.

The goal of Metabolic Efficiency

Teach your body to use more fat (and therefore less carbohydrate) at higher intensities (higher heart rate). How do you teach your body to do this? Read on.

If you continue longer aerobic exercise without a lot of available carbohydrates, your body adapts by increasing its workforce of enzymes that metabolize fat (the muffin top and bat wings…) for energy. Ahh! So that’s why we do want an aerobic base.

If you’ve fallen into “only intervals for me, please” snobbery, you’re missing out.

Many ultrarunners [now, I know you don’t come here to read about ultrarunners, but bear with me – elite athletes make mistakes too] ignore or “skip over” setting up an aerobic foundation because they don’t see the immediate benefits as they do in speed training. This is not to say that interval training or hill repeats do not produce positive changes – they do – they just don’t improve fat burning. You will be more metabolically efficient if you work on fat-burning (aerobic exercise) first, and then add in the other training regimes.

Testing for metabolic efficiency

If you do even an informal Metabolic efficiency test on yourself, where you perform a treadmill or bike exercise bout to determine response to intensity, you have a heart rate to stay under. Yes, I know, this feels a little like “fat burning zone” I so often poo-poo. The reality is, you may need to do this if you’re an interval or intensity jockey and you are still fat. If you love the results you have, you’re lean, you’re full of energy, you don’t suffer from brain fog, and you sleep better than a baby… you probably however, are not here.

You don’t even have to do a formal test to find a perceived exertion to stay under. I teach clients how to do this for themselves as well as trainers how to find this for their clients. This may be hard, training at these lower intensities – believe it or not, when you are not metabolically efficient, it is easier to run at a higher heart rate – but it is very important to stay at the lower intensity to induce the cellular responses.

Frequency is the key to successful metabolic efficiency training. Athletes need at least six to seven hours per week in this zone for results, but it is critical to have most of your training in this low zone. Sounds like a lot? If you’re taking a walk every day you’re there. Hike a little longer on the weekend and it’s not as hard as you thought. I’ve told this story – when my son was playing high school golf and summer tournaments, walking 18 or 36 holes of golf put me at the leanest ever, even though I’d been training for Ironman distance triathlons at the same time. You may not be familiar with golf but as a spectator, that’s stop start for hours. It’s extremely low intensity. It works and getting metabolically efficient is not hard. But we get it wrong.

Here’s why. You and I tend to overdo what should be low intensity exercise. We tend to under do high intensity exercise. What you have is the middle-of-the road exercise that does not improve fitness. It is “exercise” instead of “training for success.”

Metabolical efficiency nutrition

Eating too many refined carbohydrates or eating a large amount of carbohydrates at one time leads to an increase in usage of carbohydrates for energy. This may be fine if you are already a “lean-machine,” but not if you are trying to get there. Processed or refined carbohydrates (and even whole grains somewhat) cause an insulin response or spike. As insulin increases, fat break.down and oxidation (burning) significantly decreases and eventually “turns off” while this same insulin increase turns up carbohydrate oxidation. This causes us to seek out more carbohydrates and suddenly our diet becomes unbalanced as we become “carb-driven.”

Do I Want Metabolic Efficiency At 50 and Beyond?

To repeat some of the info above, essentially Metabolic Efficiency is making your body a fat burner as opposed to a sugar or carbohydrate burner. If you’re body can burn fat for fuel you will begin to lose body fat instead of storing it.

How do you become metabolically efficient? It takes a change in both your nutrition and your exercise.

Metabolically efficient exercise is more than just fat burning interval training. In fact the greatest athletes in the world, the ones that go fast and have little body fat, built their bodies on a foundation of aerobic training. That is, the long slow exercise you may have come to love in the 70s and 80s.

Metabolically efficient nutrition is lower in simple carbs, really lower in carbs overall, and higher in fat and protein percentages.

Let’s be clear that your body prefers to burn carbs. It prefers you eat them regularly and it can store them as glycogen and fat to have plenty of fuel to live on just in case. Your body is essentially the quintessential Girl scout. So if you want to reduce your body fat you’re going to have to train your body to use more fat as fuel and less carbohydrate.

It does that easier at lower intensities. Gradually if you develop a good base of aerobic fitness, your body will increase the amount of fat its burning at even slightly higher levels.

That is, if you stop feeding it immediately accessible carbohydrates.

Cross over from carbs to fat burning

It can be hard to go slow enough to help your body “cross over” to being a fat burner. If you love to go for a long slow run, even doing that can increase your heart rate to levels higher than your optimal fat burning zone.

Did you just have a flashback? Fat burning zone? Am I kidding? No. And yes, I have written and spoken about the truth about fat burning on every platform and stage I’ve ever been given the opportunity to use. More fat is actually burned at higher intensity levels and that is why we get the interval training bible out and beat it.


(you knew that was coming)

You’re not on a slow track nowhere for eternity. You, at least if you choose to shift to becoming a fat burner, are going to focus for anywhere from 4 to 10 weeks on the changes in exercise + nutrition that help you do that. Then you’re going to get off the long slow track.**This is important and where some women have remained stuck for decades.

Mini Self-Test!! Do you tend to primarily do longer cardio? Long slow walks (or even brisk walks) at a very comfortable breath rate? Then you love on your carbs? Wine, bread, pasta, potatoes, fruit is a mainstay in your diet? If you answered yes to both those questions you’re definitely helping yourself be a sugar burner and missing fat burning benefits.

That is exactly where 1 of the 2 biggest effective exercise gaps lies for most women. Has this happened to you?

  1. You are used to going long and slow thinking the longer you’re out there the better and the more calories you’re going to burn. [I am NOT condoning this, nor suggesting it is completely true or false]
  2. You have switched from day-in-day out every week doing long slow days and now you only ever do high intensity. You’ve gotten the message that the harder you go the more fat you’ll burn and you took it to heart. Even on the days you’re going longer, you go hard. If you do intervals, you go pretty hard on the recovery interval too.. you know, so you can burn more calories. [Also a fail]

The problem? Too much of the same ignores the facts:

  • You have three energy systems.
  • You are more susceptible to negative effects of stress/cortisol if you’re midlife.
  • Exercise only creates the potential for fitness: recovery is where fitness happens.
  • Long slow exercise usually increases appetite and the desire for carbohydrates.

How to Flip Metabolic Efficiency into Action:

  1. If you are nearing, at, or over 50, and a woman, you may be wondering how to increase metabolic efficiency.  A simple way you can start is to begin with at least a month of foundational exercises.  Build up your metabolism using exercises that let you do lower intensity, but longer exercise. Foods that increase metabolism for women like you include a diet that is made up of increased fat and protein.  Your nutrition protocol for helping boost metabolism should include decreasing the amount of carbohydrates you consume. Definitely sugar is not your friend if you wish to become a fat burner. Sugar feels it’s sole reason for existing is to help you store fat better.

Here’s the trick:

The best way to keep yourself into a zone that will help you use fat for fuel.. is first of all not load up on carbs before a workout. Second, keep your heart rate below that place where you first take a deep breath in and expand your rib cage to do it. Watch for it and back down. When I was first doing this 13 years ago I knew where my heart rate needed to be running and I could barely run. I had to be walking at times instead of running. Yes, I felt fine and so the ego in me said, why not run? But the want-to-be-a-leaner runner in me had to stifle that ego. Third, don’t go home and eat carbs. Wait the usual 60-120 minutes I recommend, and make it a higher fat and higher protein meal than you are likely used to having.

  1. If you’ve been doing long and slow forever without results, stick with it for four more weeks while you make more consorted efforts with your nutrition. Chances are you’ve been “eating healthy” without really knowing what that is for you right now. It’s confusing any more. Your hormones have changed. Your activity may have changed. You’re overwhelmed with Paleo, vegetarianism, forks vs knives, those who say animal protein yes and those who say never…it’s endless.

You very likely haven’t created a plan with purpose that’s integrated with an exercise program for your goals.

You can become more metabolically efficient at any age. You need to tackle it from both sides. There will be metabolically efficient meals and metabolically efficient exercise training.

Then, as a babe beyond 50, you must be sure that you’re listening to your hormones talking. [I’ll post more on Thursday about this.] They’ll whisper at first. They’ll scream eventually if you ignore them. Women in their 50s and 60s who try to go for the metabolically efficient body they want in the way a 30 something would end up with adrenal fatigue. Wisdom comes with these years. Use it. Positive thinking is important. But no amount of positive thinking overcomes body truth.

A part of the theory behind intermittent fasting is to boost fat burning by increasing glucagon. Growth hormone and testosterone are important in muscle preservation or too but they much more affected by sleep and proper weight training in midlife women.

Women may lose weight while fasting and most do so knowing that there will be regain when they return to eating. That’s important to acknowledge in order to avoid the disappointment related to fasting. Water weight lost will be water weight regained. The roller coaster is yet to be studied on peri and post menopausal women. The biggest factor in your muscle increase (rather than wasting as you age) is the exercise you do and the rest (including sleep) and the adequate protein and overall diet quality you have to support it. That is, tons of non-starchy veggies, the right type and timing of carbohydrate, and high quality protein (the building blocks of muscles) being a staple of your diet .

You can’t go back to eating junk and retain any benefits of either metabolic efficiency or intermittent fasting. But you also shouldn’t go back to eating a low calorie, low fat diet either. Fast and feast usually works best. It’s life. Cavemen did it, right? They found food and enjoyed it but it may have been long period of time between “kills.” It’s VERY important to realize restriction of calories for weeks, months, or years, on end is not the answer. If you’re still defaulting to looking for the magic bullet you’ll be better off getting moving in the weight room first and foremost. That is the top of the pyramid for results that will flip 50 for you.

The first muscle to work with is between your ears. Are you ready for permanent change? That is, permanently exercising with weights every week. While you travel, celebrate holidays, have stressors at work. Not when it’s a “good time” to start because there’s not much going on. Are you serious? You will not have much going on when you’re dead. You need the strength, the stamina, the resilience, and the confidence that comes from lifting weights and feeling/looking as good as you want to NOW! Life is crazy messy.

A short “metabolic reset” can make a big difference, as long as you do have first a foundation of:

  • Exercise
  • Sleep
  • High quality nutrition type and timing

Share your thoughts and your experience with me! Have you tried to become metabolically efficient? Are you confused by how to start? Comment below!

Then, read Thursday’s blog this week!

Spread the love
Scroll to Top

Learn how to measure!

Prefer video format?
– Click/Tap Play Below –

how to measure
Play Video about how to measure
how to measure

Circumference outside of both arms, at the armpit

Right Triceps
Halfway btwn shoulder & elbow, arm extended.

Find the widest point of girth at the hips

Right Thigh
Standing with weight on both legs, measure halfway between knee cap and hip flexor

Right Calf
Standing with weight on both legs, find the largest point of calf.

how to measure woman outline

Measure from the rib cage just under breasts at bra line

At the belly button/umbilicus

Prefer video format?
– Click/Tap Play Below –

how to measure
Play Video about how to measure

Get Notified On The Next Session

Just enter your name & email to be notified on the next training…

Flipping Fifty Logo