Most people think fatigue is a sleep problem.

But the truth is… sleep is often just a symptom.

In this episode, Zane breaks down why so many people—especially after 40—feel exhausted even when they're getting 7–8 hours of sleep.

The real issue often comes from under-fueling, chronic fasting, low carb diets, and excessive training, which drive up stress hormones like cortisol and disrupt recovery.

Zane shares the mistakes he made for years with fasted workouts, low-carb dieting, and overtraining, and explains how these habits can impact:

• Thyroid function
• Testosterone levels
• Sleep quality
• HRV and recovery
• Energy and mood

You'll also learn how to properly fuel your body for better energy, deeper sleep, and sustainable performance.

If you're tired all the time, this episode could completely change how you think about recovery.

Download Zane's Free Fit Over 40 Plan:
👉 https://free40plan.com

00:00 Why You're Still Tired
00:45 Sleep Is a Result of Your Day
02:10 The Hidden Cause of Poor Sleep
04:00 My Personal Low Carb & Fasting Mistake
05:40 Underfueling and Stress Hormones
07:10 Cortisol, Adrenaline, and Glucose Production
09:30 How Fasting Disrupts Sleep
11:30 Why You Wake Up at 2–3 AM
13:00 Fasted Workouts and Hormone Stress
15:10 Why Recovery Changes After 40
17:00 HRV, Heart Rate, and Recovery
18:40 The Mood and Energy Connection
20:10 Why Metabolic Stress Isn't Strength
22:00 Eat Less, Move More Is Wrong
23:40 How Much Protein You Actually Need
25:20 The Right Way to Eat Carbohydrates
27:30 Foods That Support Recovery
29:00 Training Smarter After 40
30:20 Managing Stress and Recovery
31:50 Why Sleep Starts When You Wake Up
33:10 Strategy Beats Extreme Discipline
35:20 Why Fatigue Is a Fuel Problem
36:00 Free Fit Over 40 Plan

Many people struggling with fatigue, weight gain, brain fog, or low libido may actually be dealing with thyroid dysfunction — and not even know it.

In this episode of Healthy AF, Zane explains how common lifestyle habits like low-carb dieting, intermittent fasting, overtraining, chronic stress, and sleep deprivation can quietly disrupt thyroid function and slow your metabolism.

You'll learn why markers like T3, reverse T3, and TSH matter more than most standard lab panels suggest, how the body adapts to low energy availability, and why many people with thyroid symptoms are often told their labs look "normal."

Zane also breaks down the role of insulin, leptin, liver glycogen, and carbohydrate intake in thyroid hormone conversion — and why reintroducing the right foods can often restore metabolic function.

If you've ever struggled with low energy, stubborn weight gain, cold intolerance, or declining performance despite dieting and training harder, this episode will help you understand what may really be happening inside your metabolism.

👇 Download Zane's Free Plan
https://free40plan.com/

Follow Zane
IG: https://www.instagram.com/zanegriggsfitness

Supportive research

Low carb diet increases incidence of REDs and low T3⁠
https://pubmed.ncbi.nlm.nih.gov/40639795/%E2%81%A0
⁠
Low carb diet reduces T3 in athletes⁠
https://blogs.bmj.com/bjsm/2023/08/14/a-bad-situation-made-worse-low-carbohydrate-intake-amplifies-low-energy-availability-hormonal-disturbances/⁠
⁠
Low carb diet induces low thyroid function⁠
https://pmc.ncbi.nlm.nih.gov/articles/PMC11558958/⁠
⁠
Keto diet reduces thyroid function⁠
https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0269440⁠

www.free40plan.com

00:00 – Introduction: Thyroid Health and Metabolism
00:40 – Remembering Charlie
02:00 – Common Symptoms of Low Thyroid
03:30 – How Thyroid Affects Metabolism and Energy
04:30 – Hormonal and Cardiovascular Effects of Thyroid Dysfunction
05:30 – Why Thyroid Issues Often Go Undiagnosed
06:30 – Stress, Overtraining, and Aggressive Dieting
08:00 – How Thyroid Hormones Work (T4, T3, Reverse T3)
09:40 – What Low-Carb Diets Do to Thyroid Function
11:00 – Low Energy Availability in Athletes
12:30 – Why Your Body Interprets Low Carb as Scarcity
14:00 – The Impact of Fasting on Thyroid Hormones
15:30 – Liver Glycogen and Overnight Stress Hormones
17:00 – Why High Performers Are Vulnerable
18:30 – Insulin, Leptin, and Thyroid Signaling
20:00 – Optimal Thyroid Lab Ranges Explained
22:30 – Why Symptoms Matter More Than "Normal" Lab Ranges
24:30 – How Thyroid Issues Affect Testosterone in Men
26:00 – Insulin Signaling and Thyroid Conversion
28:00 – Low Carb vs Insulin Resistance: Different Labs, Same Symptoms
31:00 – Why Leptin Is the Missing Link
33:00 – Reintroducing Carbs to Restore Thyroid Function
35:00 – LDL Changes After Increasing Carbohydrates
36:30 – Body Temperature and Metabolic Rate
37:30 – Training, Recovery, and Sleep
38:30 – Best Carbohydrate Sources for Thyroid Health
41:00 – How Much Carbohydrate You Actually Need
43:00 – Macro Ratios for Fat Loss vs Performance
45:00 – What Indigenous Diets Teach Us About Metabolic Health
47:00 – How Ultra-Processed Foods Disrupt Energy Production
49:00 – The Real Cause of Fat Gain and Metabolic Dysfunction
51:00 – Why "Calories In Calories Out" Misses the Real Problem
53:00 – Fixing Metabolism Through Food Quality and Energy Availability

Most men focus on body weight, workouts, or body fat… but those numbers don't tell the full story.

In this episode of Healthy AF, Zane breaks down the five blood markers every man over 40 should be tracking if they want to stay strong, energized, and metabolically healthy for decades to come.

These biomarkers can reveal problems years before symptoms appear and help you catch issues related to metabolic dysfunction, heart disease, inflammation, testosterone decline, and prostate health early.

You'll learn why markers like fasting insulin and fasting glucose often reveal metabolic issues long before diabetes develops, how free testosterone reflects metabolic stress, and why inflammation markers like hs-CRP matter for long-term health.

Zane also explains how lifestyle factors such as poor sleep, chronic stress, excessive fasting, overtraining, and ultra-processed foods can quietly push these numbers in the wrong direction.

If you're over 40 and serious about longevity, performance, and metabolic health, these are the numbers you need to know.

👇 Download Zane's Free Plan
https://free40plan.com/

Follow Zane
IG: https://www.instagram.com/zanegriggsfitness/

00:00 – 5 Blood Markers Every Man Over 40 Should Know
00:55 – Why Body Weight and Workouts Aren't Enough
01:40 – Marker #1: Fasting Insulin (Earliest Warning Sign)
02:50 – Ideal Fasting Insulin Range
04:00 – What Causes Insulin Resistance
05:05 – Marker #2: Fasting Glucose
06:00 – Why Chronically High Glucose Damages Blood Vessels
07:20 – Low-Carb, Fasting, and Elevated Blood Sugar
08:25 – Ideal Blood Sugar Range
09:15 – Stress Hormones and the "Dawn Effect"
11:00 – Marker #3: Free Testosterone
12:00 – Stress, Fasting, and Testosterone Suppression
13:20 – Ideal Free Testosterone Range
14:10 – Marker #4: hs-CRP (Inflammation Marker)
15:00 – What Drives Chronic Inflammation
15:40 – Visceral Fat, Diet, and Alcohol Effects
16:00 – Marker #5: PSA (Prostate Health)
17:00 – Testosterone and Prostate Cancer Myths
18:20 – Why You Should Start Tracking These Markers Early
19:10 – Why "Normal" Lab Ranges Aren't Optimal