Podcast Summary:

The Metabolic Classroom with Dr. Ben Bikman
Host: Insulin IQ
Episode: How Glucose Overload Breaks Your Metabolism (And How to Fix It)
Date: February 2, 2026

Overview

In this episode, Dr. Ben Bikman delivers a focused "mini-lecture" on the critical metabolic consequences of chronic glucose overload, particularly how it disrupts the NAD to NADH ratio within our cells, fueling insulin resistance, mitochondrial dysfunction, and ultimately a self-perpetuating cycle of metabolic disease. With clear, practical explanations, Dr. Bikman demystifies the biochemistry behind glucose metabolism while emphasizing actionable strategies—primarily lifestyle choices—for restoring metabolic health.

Key Discussion Points & Insights

1. Introduction to NAD/NADH and Insulin Resistance

[02:08]

• NAD (nicotinamide adenine dinucleotide) is like a "rechargeable battery" in the cell, cycling between its oxidized form (NAD) and reduced form (NADH).
• The NAD/NADH ratio is a "critical determinant of such things as insulin sensitivity" (Dr. Bikman, [03:35]).
• High NAD/NADH ratio = a healthy metabolic state.
• When NADH accumulates and NAD drops, insulin resistance can emerge.

Quote:
"Think of NAD as a rechargeable battery in your cells. It accepts electrons during one process and donates them during another...this constant cycling is essential not only for energy production...but also things like DNA repair, cell signaling, and more."
— Dr. Ben Bikman ([02:35])

2. How Excess Glucose Shifts the NAD/NADH Ratio

[06:00]

• Overeating, especially refined carbs, floods cells with glucose, overloading the mitochondria.
• Excess glucose increases the production of NADH, which can't be recycled quickly enough—like a "traffic jam" ([06:50]).
• Consequences:
  • Inhibits key enzymes and sirtuin activity (proteins important for mitochondrial health).
  • Favors the production of harmful lipid metabolites (diacylglycerols, ceramides) that block insulin signaling.
  • Activates the hexosamine biosynthetic pathway, further impairing insulin sensitivity.
  • Triggers mitochondrial dysfunction and increased oxidative stress.

Quote:
“When there's too much glucose coming in...the mitochondria become overwhelmed. They can't process all that NADH quickly enough. It's like a traffic jam on the highway...”
— Dr. Ben Bikman ([07:01])

3. Pseudo-Hypoxia and Reductive Stress

[11:00]

• Chronically elevated blood glucose (as in prediabetes/diabetes) causes cells to behave as if oxygen-starved—a condition termed "pseudo-hypoxia" or reductive stress.
• Hyperglycemia also activates the polyol pathway, depleting antioxidant reserves (NADPH) and generating even more NADH.
• This combination creates a harmful metabolic environment, particularly in high-sugar-exposed tissues (eyes, nerves, kidneys).

Quote:
“When glucose levels are too high, they behave metabolically as if they're starved of oxygen, even when the oxygen is abundant.”
— Dr. Ben Bikman ([12:15])

4. Metabolic Overload: A Vicious Cycle

[15:30]

• High glucose → skewed NAD/NADH ratio → mitochondrial oxidative stress → insulin resistance → more hyperglycemia.
• Unlike simple excess calories (where the ratio can recover), chronic hyperglycemia has no metabolic "break", leading to constant cellular stress.

Quote:
"High glucose alters the NAD to NADH ratio. That ratio then causes mitochondrial dysfunction and oxidative stress. This mitochondrial damage...compromise[s] insulin resistance, which leads to higher blood glucose. And the higher blood glucose just feeds the cycle further."
— Dr. Ben Bikman ([16:35])

5. Causes of Low NAD/NADH Ratio

[17:30]

• Chronic carbohydrate overload (especially refined carbs).
• Aging (NAD declines by more than 50% from young adulthood to old age).
• Alcohol consumption (rapidly depletes NAD, contributing to liver and metabolic disease).
• Sedentary behavior (reduced NAD production and recycling).

6. Evidence-Based Solutions to Restore Metabolic Health

[20:53]

A. Carbohydrate Restriction

• Prioritize avoiding refined carbohydrates (“If the carbs come in a bag or a box with a barcode, they are carbs to avoid.” — Dr. Bikman, [18:16]).
• Results in reduced NADH production, helps rebalance the ratio.
• Supported by studies showing improved ratios in just weeks ([20:55]).

B. Physical Activity

• Drives energy demand, increasing NADH recycling to NAD.
• Stimulates new NAD production and mitochondrial health.

C. Time-Restricted Eating/Intermittent Fasting

• Reduces constant glucose influx, allows cells to restore NAD.
• Activates sirtuins (beneficial to metabolism).

D. Prioritize Sleep

• Sleep deprivation reduces NAD, impairs the desirable ratio.

E. Minimize Alcohol

• Avoids the rapid shift and depletion of NAD, especially in the liver.

7. Supplements: NAD Boosters (NR/NMN) — Science vs. Hype

[23:00, 30:14]

• NR (nicotinamide riboside) & NMN (nicotinamide mononucleotide) are marketed as NAD-boosters.
• Animal studies show promise, human data is limited and underwhelming.
  • Human trials: Boost blood NAD levels, but most do not show significant improvements in metabolic health or insulin sensitivity.
  • Possible issues: poor bioavailability, insufficient dosing, and not addressing root causes (e.g., ongoing glucose overload).
• May have a limited role in special populations (genetic NAD deficiencies, advanced age, etc.), but not for the general public.

Quote:
“A person eating a high carb diet, remaining sedentary and sleeping poorly isn't going to supplement their way to metabolic health with NR or NMN.”
— Dr. Ben Bikman ([30:30])

8. Practical Recommendations (“What Actually Works”)

[31:45]

• “The most prudent approach...is to focus on the interventions that we know work: control carbohydrate intake...exercise regularly...incorporate some time restricted eating...optimize your sleep, and minimize alcohol consumption.” (Dr. Bikman, [30:30])
• Restore both sides of the NAD/NADH ratio: reduce NADH production, support NAD regeneration.
• For those optimizing lifestyle: Trying supplements is "reasonable", but expectations should be “tempered and even quite realistic.”

Memorable Quotes

• “A healthy NAD/NADH ratio is both a marker and, I would say, a mediator of metabolic health.”
  — Dr. Ben Bikman ([31:00])

• “Be physically active, control your carbs, incorporate some periods of fasting, prioritize sleep...these fundamental strategies are going to work at more of a deeper molecular level to restore metabolic health by restoring the ratio.”
  — Dr. Ben Bikman ([32:40])

Timestamps for Key Segments

| Timestamp | Segment Description | |-----------|---------------------------------------------------------------| | 02:08 | Introduction to NAD/NADH and metabolism | | 06:00 | The “traffic jam” — How glucose overload impacts the ratio | | 11:00 | Pseudo-hypoxia and diabetic complications explained | | 13:30 | The polyol pathway and further NADH accumulation | | 15:30 | The vicious cycle of metabolic overload | | 17:30 | Causes of low NAD/NADH ratio: diet, aging, alcohol, inactivity| | 20:53 | Evidence-based solutions: carb restriction, activity, fasting | | 23:00 | NAD precursor supplements: evidence and limitations | | 31:00 | Practical lifestyle recommendations — what actually works | | 32:40 | Closing thoughts: Rebalancing NAD/NADH the right way |

Flow, Tone, and Takeaways

Dr. Bikman’s tone throughout the mini-lecture is pragmatic, plainly spoken, and respectful of scientific nuance. He emphasizes that, while molecular supplements are enticing, lasting metabolic health is realistically achieved by consistent, evidence-backed lifestyle interventions:

• Lower refined carbohydrate intake
• Move your body
• Fast occasionally
• Protect your sleep
• Skip the alcohol

His analogies ("NAD as a battery," "traffic jam," "pseudo-hypoxia") make complex concepts accessible and memorable, and he maintains a focus on empowering listeners with usable science, cautioning against shortcut solutions until the evidence supports them.

For Listeners

This episode is a must-listen for those curious about:

• The deep links between diet, metabolism, and cellular health
• Why simply “boosting” molecules like NAD isn’t a magic fix
• How to strategically use food, exercise, and routines to reverse and prevent metabolic dysfunction

If you’re seeking actionable and trustworthy metabolic advice that goes beyond headlines and hypes, Dr. Bikman delivers clear, evidence-driven steps you can start applying today.