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The Best Blood Tests to Get Before Starting Your Metabolic Flexibility or Ketosis Journey

If you’re planning to improve your metabolic health, reverse insulin resistance, lose fat, or start fasting or a ketogenic diet, there’s one step I strongly recommend first:

Get comprehensive baseline blood work.

Not because something is wrong with you.
But because metabolic flexibility is about understanding how your body uses fuel and how it responds to change.

If you want a simple way to do this without fighting insurance or chasing lab orders, I recommend using Function Health. You can learn more and get started here:
👉 Get comprehensive labs with Function Health

When you have real lab data, you stop guessing and start making personalized, science-based decisions about your health.

What Is Metabolic Flexibility?

Metabolic flexibility is your body’s ability to switch between burning glucose and burning fat efficiently.

A metabolically flexible metabolism can:

  • Burn glucose after meals

  • Switch to fat and ketones between meals or during fasting

  • Maintain stable energy without constant hunger

  • Improve insulin sensitivity and fat-burning capacity

When someone is metabolically inflexible or insulin resistant, they often:

  • Feel hungry shortly after eating

  • Struggle with intermittent fasting

  • Have difficulty losing weight

  • Store fat easily

  • Experience blood sugar swings and cravings

Two of the most powerful tools to restore metabolic flexibility are:

  • Intermittent fasting and time-restricted eating

  • Nutritional ketosis or low-carbohydrate, fat-adapted eating

But before changing your diet or starting fasting, it’s critical to understand your metabolic baseline.

Why Blood Tests Matter Before Starting Keto or Fasting

Blood tests reveal:

  • Your insulin sensitivity

  • Your blood sugar control

  • Your fat-burning potential

  • Your inflammation levels

  • Your cardiovascular risk

  • Your hormone and nutrient status

Without labs, you’re guessing.
With labs, you’re using precision health data to guide your metabolic healing.

Below are the most important lab tests for metabolic health I recommend before starting ketosis or a fasting protocol.

1. Fasting Insulin (The Most Important Marker for Insulin Resistance)

Fasting insulin is one of the most important and most overlooked blood tests for metabolic health.

It shows how hard your body is working to keep blood sugar normal.

You can have normal glucose and still have high insulin, which means:

  • Your body is stuck in fat-storage mode

  • Fat burning is impaired

  • Weight loss is harder

  • Fasting feels more difficult

  • Metabolic flexibility is reduced

Elevated fasting insulin is often the earliest sign of insulin resistance, long before prediabetes or type 2 diabetes appears.

2. Hemoglobin A1C (Your 3-Month Blood Sugar Average)

Hemoglobin A1C measures your average blood glucose over the past 2 to 3 months.

It helps:

  • Detect prediabetes and type 2 diabetes

  • Identify chronic blood sugar elevations

  • Track long-term improvements in glucose control

Even “high-normal” A1C values can indicate:

  • Poor metabolic flexibility

  • Frequent glucose spikes

  • Increased long-term metabolic risk

This is a key progress-tracking marker during metabolic recovery.

3. Fasting Glucose

Fasting glucose shows:

  • How well your liver regulates blood sugar overnight

  • Whether your body maintains stable blood sugar without frequent meals

On its own, it’s limited. But combined with:

  • Fasting insulin

  • A1C

…it provides a much more accurate picture of metabolic health and insulin sensitivity.

4. Leptin (Your Energy Signaling Hormone)

Leptin is best described as your energy signaling hormone.

It’s produced by fat cells and tells your brain:

  • How much energy you have stored

  • Whether it is safe to burn fat or conserve energy

When leptin signaling is working properly:

  • Hunger is appropriate

  • Energy expenditure is normal

  • Fat burning is easier

  • Fasting feels more sustainable

In metabolic dysfunction, many people develop leptin resistance, where leptin levels are high but the brain does not respond. This leads to:

  • Increased hunger

  • Lower energy expenditure

  • Fat loss resistance

  • Persistent fat-storage signals

This makes leptin a critical marker in metabolic health and weight loss resistance.

5. Cholesterol Panel (Interpreted Through a Metabolic Health Lens)

A full lipid panel includes:

  • Total cholesterol

  • LDL cholesterol

  • HDL cholesterol

  • Triglycerides

From a metabolic perspective:

  • High triglycerides and low HDL often indicate insulin resistance

  • As metabolic health improves, triglycerides usually decrease and HDL increases

Cholesterol should always be interpreted in context with insulin, glucose, and inflammation markers.

6. Vitamin D (A Key Metabolic and Immune Marker)

Vitamin D plays a role in:

  • Insulin sensitivity

  • Immune health

  • Inflammation control

  • Muscle function

  • Hormone signaling

  • Mood and energy

Low vitamin D levels are extremely common and are associated with:

  • Worse metabolic health

  • Higher inflammation

  • Increased insulin resistance

Optimizing vitamin D is an important part of a comprehensive metabolic health strategy.

7. Additional Blood Tests That Support Metabolic Health

Depending on the panel, it’s also helpful to check:

  • Comprehensive metabolic panel (liver, kidney, electrolytes)

  • hs-CRP (inflammation)

  • Thyroid function tests

  • Uric acid

  • Ferritin and iron status

These markers influence:

  • Energy levels

  • Exercise tolerance

  • Fasting tolerance

  • Weight loss response

  • Overall metabolic resilience

Why I Recommend Function Health for Comprehensive Lab Testing

This is why I recommend Function Health for metabolic health lab testing.

Function Health:

  • Provides comprehensive blood testing beyond standard primary care panels

  • Is cost-effective compared to ordering labs individually

  • Includes advanced metabolic and cardiometabolic markers most doctors don’t routinely order

  • Gives you a systems-based view of your health

  • Removes barriers when your PCP won’t order the labs you want or need

Many primary care practices are limited by insurance rules and outdated screening models. Function Health allows you to be proactive instead of reactive with your health data.

👉 You can explore Function Health here and get your baseline labs started

The Bottom Line on Metabolic Flexibility and Lab Testing

Metabolic flexibility is the foundation of:

  • Fat burning

  • Stable energy

  • Healthy blood sugar

  • Long-term metabolic health

Fasting and ketogenic diets are powerful tools, but lab data makes them safer, more personalized, and more effective.

If you’re serious about reversing insulin resistance, improving metabolic health, and restoring your body’s ability to burn fat efficiently, start with the right blood tests.

👉 Start here with Function Health

Why You’re Tired, Craving, and Stuck (And It’s Not a Willpower Problem)

If you’ve ever felt shaky when you miss a meal, crashed a few hours after eating, or wondered why your energy and weight feel “stuck” no matter how hard you try, I want you to hear this first:

This is not a character flaw. And it’s not a discipline problem.

For many people, it’s a metabolism problem. More specifically, it’s a problem of metabolic flexibility.

And the good news? Your body was designed to adapt. It’s not broken. It’s just been trained into a very narrow way of using fuel.

What Is Metabolic Flexibility (In Plain English)?

Metabolic flexibility is simply your body’s ability to switch between burning sugar and burning fat depending on what’s available and what you’re doing.

A flexible metabolism can:

  • Go longer between meals without panic

  • Handle carbs without crashing

  • Use fat for fuel when needed

  • Keep energy, focus, and hunger more stable

An inflexible metabolism, on the other hand, tends to:

  • Feel shaky, irritable, or unwell when meals are delayed

  • Crash or crave sugar a few hours after eating

  • Depend on frequent snacks or caffeine

  • Feel stuck in a cycle of highs and lows

This isn’t about being “good” or “bad” at dieting. It’s about what your metabolism has been trained to do over time.

And just like any system in the body, it can be retrained.

Three Common Metabolic States I See All the Time

Most people fall into one of these three broad categories.

1. The “Always Running on Sugar” Metabolism

This is the most fragile state.

People here often:

  • Feel unwell if they skip a meal

  • Crash after eating

  • Crave carbs or sweets

  • Need frequent snacks or caffeine

  • Struggle with energy and focus

Their body is basically stuck in glucose-only mode. It hasn’t practiced using fat for fuel in a long time, so any gap in food feels like an emergency.

This is not the group that needs extreme fasting or aggressive dieting. This group needs stability first. Think of it like metabolic rehab.

2. The “Somewhat Stable but Inconsistent” Metabolism

This is the middle ground.

People here might:

  • Do okay most days

  • Still crash under stress or after carbs

  • Notice energy swings with schedule changes

  • Be able to fast a little, but not comfortably

  • Feel like progress comes and goes

This is a great place to be, because it means your metabolism is ready to start training fat-burning more intentionally, just not in an extreme or punishing way.

This is where gentle, smart shifts can make a big difference.

3. The “Adaptable and Resilient” Metabolism

This is what we’re aiming for.

People here tend to:

  • Have more stable energy and hunger

  • Tolerate longer gaps between meals

  • Handle carbs more strategically

  • Recover better from stress or schedule changes

  • Use both sugar and fat as fuel when needed

This is where tools like ketosis, fasting, and performance training become options, not stressors.

This Isn’t About Punishment. It’s About Training.

One thing I want to be very clear about:
Your body is not your enemy.

God designed your body to adapt, to heal, and to become more resilient over time. When something feels hard, it’s usually not because you’re failing. It’s because your body hasn’t been trained there yet.

Just like you wouldn’t expect someone to run a marathon without building up to it, you shouldn’t expect your metabolism to jump straight into fasting, keto, or extreme plans without preparation.

We build capacity first. Then we build flexibility. Then we refine and optimize.

That’s a much more sustainable, much more respectful way to work with your body.

So Where Should You Start?

Instead of guessing, I created something simple and practical:

👉 The 3-Minute Metabolic Check

It’s not a diagnosis. It’s not a test. It’s a quick self-check to help you see:

  • How stable your metabolism is right now

  • Which general category you’re in

  • And what your smartest next step should be

No email required. No pressure. Just clarity.

👉 Take the 3-Minute Metabolic Check

A Final Encouragement

If your body feels tired, reactive, or stuck right now, that doesn’t mean you’ve failed.

It means your body is asking for a different approach.

With the right steps, in the right order, your metabolism can become more resilient, more adaptable, and more peaceful to live in. And that’s not just about weight or numbers. It’s about having the energy and clarity to live the life you’re called to live.

One small, wise step at a time. 💛



Ketosis: The Metabolic State That Mimics Fasting and Heals from Within

When most people hear the word “ketosis,” they think of weight loss, and yes, it’s an effective fat-burning state. But what often gets overlooked is that ketosis isn't just about shedding pounds. It’s a powerful metabolic state that mimics many of the same benefits as extended fasting, without going days without food.

And for those of us trying to reduce inflammation, support gut health, and reclaim energy and mental clarity, that’s a big deal.

Let’s break it down.

What Is Ketosis?

Ketosis is a natural metabolic state where your body shifts from burning glucose, or sugar, to burning fat for fuel. This happens when carbohydrate intake is very low, either because you’re fasting or you’re eating in a way that limits carbs, like a ketogenic or low-carb, high-fat lifestyle.

When you enter ketosis, your liver begins producing ketones from fat. These ketones are clean, efficient energy sources not just for your body, but especially for your brain.

 Ketosis vs. Extended Fasting: Similar Benefits Without the Stress

Extended fasting, think 24 to 72 hours or more, triggers powerful healing processes like autophagy, insulin sensitivity, and anti-inflammatory effects. But it’s not always practical or healthy for everyone to fast that long regularly.

Here’s where nutritional ketosis comes in.

In a state of ketosis, your body mimics many of the benefits of extended fasting while still receiving essential nutrients. This includes:

Reduced inflammation
Ketones like beta-hydroxybutyrate, or BHB, have direct anti-inflammatory effects at the cellular level. This is one reason people in ketosis often report reduced joint pain, better digestion, and clearer skin.

Mental clarity and neuroprotection
The brain loves ketones. They provide a steady, stable energy source, unlike the blood sugar highs and crashes from a high-carb diet. Ketosis is being studied for its benefits in Alzheimer’s, epilepsy, and other neurological conditions.

Improved metabolic flexibility
When you’re in ketosis, your body becomes better at switching between fuel sources. This means more stable energy, better blood sugar control, and fewer cravings.

Ketosis and Gut Health

This one surprises a lot of people, but yes, ketosis can be great for your gut.

Many people enter ketosis and notice less bloating, more regular bowel movements, and even remission of chronic digestive issues like IBS.

Here’s why:
A low-carb, whole-food keto diet naturally eliminates many gut irritants like sugar, seed oils, and processed carbs.
Ketosis supports a healthy gut microbiome by reducing inflammation and feeding beneficial bacteria with fiber-rich vegetables, fermented foods, and prebiotics.
Ketones themselves may even have a protective effect on the gut lining, helping prevent “leaky gut” and improving intestinal barrier function.

Real Nourishment, Not Just Restriction

Unlike prolonged fasting, ketosis doesn’t mean starvation. It’s about nourishing your body with healthy fats, quality proteins, and nutrient-dense, low-glycemic vegetables. You’re still eating, just strategically.

The result? You can feel the same mental clarity, hunger control, and healing benefits of fasting without the burnout, blood sugar dips, or stress on the body.

Final Thoughts

Whether you’re easing into a low-carb lifestyle or you've been curious about ketosis for a while, know this: You don’t have to fast for days to unlock deep healing. The metabolic state of ketosis can deliver so many of those same benefits while helping you feel grounded, nourished, and strong.

Your body was designed to heal. Ketosis is just one tool that helps it do exactly that.


When God Calls You Into the Unknown: What I Learned from Acts 20:22

This Sunday at Canvas Church Alachua, Pastor Kevin McNeil delivered a powerful sermon on Acts 20:22, where Paul says:

“And now, compelled by the Spirit, I am going to Jerusalem, not knowing what will happen to me there.” (Acts 20:22, NIV)

Paul didn’t have all the answers. He just had the call. And that’s where many of us find ourselves when we’re stepping into something new. Pastor Kevin explained what this process often looks like when the Holy Spirit is leading us into purpose:

  1. Righteous restlessness
  2. Certain uncertainty
  3. Predictable resistance
  4. Uncommon confidence

That breakdown hit me hard because it describes exactly what I’ve been walking through in this season.

How I’m Living This Out

Over the past year, I’ve felt a holy stirring. A deep inner conviction that I was meant to serve in a new way. I’ve spent over 15 years in clinical pharmacy, but something in me knew it was time to step beyond the traditional model and start speaking directly to people about metabolic healing, root-cause wellness, and faith-driven health.

I didn’t have a full blueprint. And if I’m honest, I still don’t. But I couldn’t ignore the righteous restlessness. I knew I was being called out of comfort and into impact.

Then came the certain uncertainty. There’s been trial and error. Questions about income, identity, and what success would even look like. But I’ve kept moving forward because I know the One who called me.

I’ve faced predictable resistance too. Self-doubt. Criticism. Delays. Even spiritual warfare. And yet, God has consistently shown up with uncommon confidence. Just enough encouragement. Just enough clarity. Just enough provision to take the next step.

This line from Pastor Kevin stayed with me:

“The struggle you’re facing today is strengthening you for the weight of success you’ll be responsible for tomorrow.”

That’s the season I’m in. And maybe it’s the season you’re in too.

How You Might Be Living This Too

Maybe you feel it. That gentle, persistent tug in your spirit. A call to shift careers, write the book, launch the ministry, prioritize your health, speak up, walk away, or start fresh. Something that makes no sense on paper but won’t let you go.

Maybe you don’t know what’s next. You just know you can’t stay where you are. That’s certain uncertainty. Don’t wait for clarity to start obeying. Clarity often follows obedience.

And when the resistance shows up? Expect it. Resistance isn’t always a sign to turn around. Sometimes it’s confirmation you’re on holy ground. The enemy doesn’t bother people who aren’t a threat.

The good news is this: God won’t call you to something without equipping you for it. You may not feel ready, but the preparation is already happening. Even in the struggle.

A Final Word

If you’re feeling the tension of transition, like you’re being stretched, stirred, or set apart, lean into it. Let God refine you. Let the resistance train you. Let the uncertainty build your faith.

You don’t have to see the whole path. Just take the next right step.

Your obedience today is preparing you for the weight of the blessing tomorrow.

 

What Is Metabolic Healing, and Why Most Diets Miss the Mark

When most people think of improving their health, they think of cutting calories, exercising more, or jumping on the latest trendy diet. But if you’ve tried those things and still feel tired, inflamed, or stuck in a cycle of cravings and fatigue, you’re not alone.

Metabolic healing isn’t about restriction. It’s about restoration.

As a board-certified clinical pharmacist and metabolic health educator, I’ve spent years helping people uncover what’s really driving their symptoms, and more often than not, it all comes back to the metabolism.

So, what is metabolic healing?

Metabolic healing means getting your body back to a place where it can burn fuel efficiently, manage blood sugar with ease, and respond to hunger, hormones, and stress the way it was designed to.

Instead of chasing symptoms like:

• Weight gain
• Fatigue
• Brain fog
• Sugar cravings
• High blood pressure
• “Normal” labs but feeling off

We ask why those symptoms are showing up in the first place. We support the systems behind the symptoms, starting with your metabolism.

Why most diets miss the mark

Most diets focus on what to cut out: carbs, fat, calories, flavor, joy.

But your body isn’t broken, it’s just overwhelmed. And constantly restricting or depriving it sends a stress signal that often slows healing even more.

Here’s what most programs don’t address:

• How to balance blood sugar without obsessing over carbs
• How to eat in a healing order, not just track macros
• How your circadian rhythm, stress, and sleep impact weight and energy
• How movement can be simple and supportive, not punishing
• How to rebuild metabolic flexibility without fearing food

What metabolic healing looks like

In my own journey, and in the lives of so many people I’ve helped, it starts with small, powerful shifts like:

• Fiber-first eating: starting meals with veggies to blunt blood sugar spikes
• Time-restricted eating: giving your gut and hormones a rest
• Daily movement, like walks after meals or short dumbbell workouts
• Micronutrient support: replenishing what’s been depleted by stress or medications
• Root-cause mindset: asking why, not just what

You were designed to heal

God created our bodies with an incredible ability to heal when we remove the stressors and give it what it needs. Metabolic healing isn’t a quick fix. It’s a rewiring. A reclaiming. A return to the way we were meant to function.

If you're tired of chasing the next diet and you're ready to support your system from the inside out, you're in the right place.

What’s next?

In upcoming posts, I’ll break down exactly how to support your metabolism through food, movement, sleep, and mindset, and how to make it realistic for your everyday life.

Your healing doesn’t start with restriction. It starts with understanding.

Stick around. Your body is ready to heal. Let’s begin.

 

How I Found Faith, Healing, and Metabolic Freedom, and How You Can Too 

Hi, I’m Dr. Lyndsay Carlson, a PharmD, board-certified ambulatory care clinical pharmacy specialist, mom of two, and passionate believer in the body’s God-designed ability to heal. I created this space because I believe your body is not broken. It was designed by God with incredible capacity for renewal. We just need to get out of the way and give it what it needs.

 From Prescriptions to Purpose

 I’ve been practicing as a clinical pharmacist for over 15 years, focused entirely on chronic disease state management in outpatient care. My journey started in the VA system, where I completed a residency and managed chronic conditions like diabetes, hypertension, and heart failure under collaborative practice agreements.

 I quickly began to notice a pattern: patients were depending on medications to fix issues that were often caused by lifestyle choices, poor nutrition, stress, lack of movement, and more. And while medications can be lifesaving and necessary, I saw how often they became a Band-Aid for deeper root causes.

Over time, many patients didn’t feel better. They just had more prescriptions. More side effects. More co-pays. More confusion.

 But something amazing happened when I started having honest conversations with patients about why they were sick, and what they could do about it. Once people understood the root cause and saw a path to true healing, they got on board. They made changes. They started to heal.

 And it clicked for me: This is what I was meant to do.

 Faith Was Always the Foundation

 I’ve always been a Kingdom person. I’ve always prayed to be the light, to bring healing, to be used in a way that glorifies Him.

Before I ever wore a white coat, I had a bachelor’s in biochemistry and even spent a year doing pharmaceutical industry research. But deep down, I knew I wasn’t made for the lab, I was made to walk alongside real people, helping them heal from the inside out.

I now believe God led me into ambulatory care pharmacy, not just to manage disease, but to reverse it. To remind people that healing is possible, even if the world says otherwise. That your diagnosis doesn’t define you.

The Shift: From Clinical to Root-Cause, Metabolic Healing

 In recent years, I dove deep into metabolic health, learning about the incredible healing power of fasting, nutrient-dense foods, sunlight, blood sugar regulation, and the state of ketosis (not the trendy “keto diet”, I’m talking about your body’s natural metabolic flexibility).

 I realized most chronic diseases, from fatigue to insulin resistance, high blood pressure, inflammation, and brain fog, are symptoms of metabolic dysfunction.

 And the good news? You can start healing today by:

  • Eating fiber first (leafy greens, cruciferous veggies)

  • Prioritizing protein and healthy fats

  • Saving carbs for last

  • Fasting within a circadian rhythm (think 12–16 hour overnight fasts)

  • Getting morning sunlight to reset your hormones

  • Walking daily, even with a weighted vest for a metabolic boost

 None of this requires perfection. It just requires a willingness to align your daily habits with how your body (and brain) were designed to function, by God.

 What You’ll Find Here

This blog is where faith and science meet. It’s where prescriptions and prayer coexist. It’s where I’ll teach you what I wish every patient knew:

  • What true metabolic healing looks like

  • How to naturally balance blood sugar, hormones, and inflammation

  • How to support your system if you’re on medications

  • How to use fasting, movement, and real food as medicine

  • How to invite God into your healing journey

 I’ll also share tools I use daily, from supplements and clean recipes to wearable tech and workouts that fit into real life.

 Because healing isn’t a destination, it’s a lifestyle.

 Your Invitation

 If you’re ready to stop managing symptoms and start healing from the inside out, you’re in the right place.

👉 Subscribe to my newsletter for encouragement, education, and easy next steps.

📬 Have a question or want to share your story? Leave a comment or email me, I’d love to hear from you.

 Let’s heal, faithfully, metabolically, and together.

 With grace and grit,

Lyndsay Carlson, PharmD, BCACP

Clinical Pharmacist | Metabolic Healer | Mom | Believer