Home
>
Nutrition
>
Fructose Short-Circuits Glycolysis

Fructose Short-Circuits Glycolysis

First some terminology.

Fructose ... a five carbon sugar that occurs naturally in fruit, does not cause as much insulin to be secreted as glucose and tastes sweeter than glucose.

Glucose ... a six carbon sugar that is the breakdown product of glycogen(a polymer of glucose, multiple glucose units hooked together) that occurs naturally in potatoes and grains.

Glycogen ... multiple units of glucose hooked together (a polymer). What is typically called "complex carbohydrate" today.

Glycolysis ... derived from the Greek stem glyk- "sweet" and lysis meaning dissolution. The metabolic pathway for the initial utilization of glucose.

Phosphofructokinase ... the enzyme that catalyzes the reaction of fructose 6-phosphate to fructose 1,6-biphosphate. You don't need to understand anything more about this reaction other than the fact that if fructose comes from a source other than the degradation of glucose, it blocks this step for glucose until all the non-glucose derived fructose has been metabolized.

Glucose and Fructose Are Both Metabolized via Gylcolysis

Both fructose and glucose are metabolized via glycolysis. Both end up at some point as three carbon fragments. In order for glucose to be broken down into three carbon fragments it must first be metabolized to a five carbon sugar, actually fructose. This is where the trouble starts, since fructose is already a five carbon sugar. The following analogy I hope will aid in explaining this. The analogy, however, is far from perfect.

Whether we start out with separate glucose and fructose as in high fructose corn syrup or honey, or with fructose and glucose hooked together as in sucrose(common table sugar), makes no difference. As soon as sucrose hits the bloodstream, it is immediately broken down (hydrolyzed) to fructose and glucose.

Freda Fructose gets married to Gary (Glucose) Sucrose. They live happily on Sugar Lane. Both work in muscle and liver cells where they are metabolized usually into fat and slow the immune system to a crawl. They get up early in the morning and both have to get on the Glycolysis Road to get to work. Gary (Glucose) is one carbon atom heavier than Freda Fructose and because of that, he cannot cross the river on one of the lighter and faster bridges on their way to work. Freda Fructose however, being lighter, has no problem crossing the faster bridge and making the short-cut to the Glycolysis Road. Gary Glucose, however, has to get on the road well above the short-cut, since he is too heavy to take the lighter bridge short-cut.

The Phosphofructokinase Intersection

As usual Freda Fructose gets to the Phosphofructokinase intersection well before Gary Glucose. By the time Gary Glucose gets to the intersection, the traffic directing policeman is once again allowing all the Freda Fructoses to make the turn onto Glycolysis Road while, all the Gary Glucoses can do is sit in traffic and wait. Once again, Gary, and all the other Glucoses on their way to work, must sit and wait for all the Freda Fructoses to get on Glycolysis Road before they can continue.

LA Traffic Control

Traffic control sees all these Glucoses sitting stuck in traffic, just like traffic backs up everyday in LA. It reacts by injecting a lot of green lights (insulin) into the pathway for the Glucoses to get to work. Finally, all the Fructoses pass and now because there are too many green lights, all the Glucoses pass quickly. All of the sudden there are no Glucoses to be found on the Glycolysis Road. All the cells along the way that used to be able to snag some Glucose can't because there isn't any. Whether it is the excessive insulin that is the cause of so many of the lifestyle diseases we see today or, all the backed up Gary Glucoses decide to cause their own damage to the arteries they are in, I don't know. It is however, clearly established that the ingestion of sucrose (fructose and glucose) is related to many of our lifestyle diseases today including the extensive damage to the vascular system that occurs with adult onset diabetes mellitus. I know, my damaged arteries are up on this site.

Hypoglycemia

Now you begin to feel lightheaded, dizzy and a bit disoriented. Traffic control has injected too many green lights and the concentration of glucose drops precipitously. The brain starts to complain because it no longer has enough glucose to function. If the blood sugar gets low enough, serious complications can occur.

Fructose and Glucose Together

The combination of fructose and glucose should be avoided as much as possible. When you eat your fruit, try to allow at least an hour or preferably two, before eating potatoes, whole grains or rice. Also avoid as much as you can sucrose, high fructose corn syrup, honey and maple syrup or, any sweetener that has as it main ingredients, fructose and glucose.

Other Sweeteners

Brown Rice Syrup

Brown rice syrup is roughly about 45% maltose (two glucose units hooked together), 50% complex carbohydrates and 3% glucose. No glucose and fructose together but still sweet and I have known some people who can even get hypoglycemic from it.

Barley Malt Syrup

Made from whole barley it is about 65% Maltose and 30% complex carbohydrates.

Fruit Concentrates

These are usually combinations of glucose, fructose and sucrose and should be avoided.

Maple Syrup

Maple syrup is about 65% sucrose and should be avoided.

Today's Health Tip:

If you want sweet, you are safest with stevia. Next would be sweeteners derived from rice and barley. Sucrose, high fructose corn syrup, maple syrup and fruit juice concentrates should be avoided.

Reference:
Stryer Biochemistry Fourth Edition

**************
To really get off of sweets and "deprogram a sugar-coated palate," the MericleDiet is hard to beat. Generous servings of organic complex carbohydrates will keep you and your brain happy. To visit the MericleDiet follow the link below.
http://www.drmericle.com
**************

One of our readers Wendy in the UK writes:

Just to let you know that according to the website below that takes you to Carol Bond Health Foods it is spelt Stevita. I couldn't find it anywhere on the site and through asking the chat section it was spelt differently. Thought you would like to know so that you can let the other newsletter recipients know.
Regards...
Wendy

PS Really enjoy the newsletter. Find it very informing so thank you. Gave up drinking milk last year after reading your article! Feel much healthier as a result.
**************

To take Stevia for a test drive or purchase some online follow the link below. I had luck just searching stevia but you could also search the product "Stevita."
http://www.drmericle.com
Thanks for your time.

DrMericle.com is devoted to achieving optimal health and peak performance through diet and lifestyle change. Dr. Mericle brings together a unique blend of formal training in organic chemistry and biochemistry, medical education, 29 marathons, 3 Hawaii Ironman competitions and a lot of practical real life experience.

maid service near Lake Forest ..

In The News:

New phishing platform QRR targets Microsoft 365 users across 1,000 domains in 90 countries. Learn how to spot fake login pages and protect your accounts.

OpenTable now uses AI to track your dining habits and share insights with restaurants. Learn what data they collect and how to protect your privacy.

Google's discontinued Nest thermostats still secretly upload home data to company servers despite losing smart features, raising serious privacy concerns.

New Android malware NGate steals NFC payment codes in real-time, allowing criminals to withdraw cash from ATMs without your card. Learn protection tips.

DoorDash confirms data breach exposing customer names, emails, addresses after social engineering attack. Learn how to protect yourself from scams.

Concerned about Google's AI scanning your Gmail? Learn how to disable Gemini features that access your emails, Drive files and Chat messages for privacy.

Google warns Android users about dangerous fake VPN apps hiding malware that steals passwords, banking details and personal data from phones and tablets.

Apple's digital passport feature lets iPhone users breeze through TSA checkpoints this holiday season using Digital ID technology at 250+ airports.

A new phishing scam targets family photos with fake "Cloud Storage Full" alerts. Criminals steal credit card information through fake sites. Learn protection tips.

South Korean scientists create ultra-thin fabric muscles that turn clothes into robotic assistants, lifting 33 pounds while weighing under half an ounce.

Archer Aviation has acquired Hawthorne Airport for $126M to launch an LA air taxi network ahead of the 2028 Olympics, featuring AI-powered eVTOL operations and next-gen aviation tech.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

Fake AI apps disguised as "ChatGPT" and "DALL·E" are flooding app stores with dangerous malware that steals data and monitors users without detection.

Fake buyers demand specific vehicle reports from unknown sites to steal credit card information from car sellers, but warning signs can help identify these scams before paying.

Android users can now manage apps across multiple devices more easily with Google Play Store's updated remote uninstall button in the latest update.

NASA's Perseverance rover discovers shiny metallic rock on Mars that could be a meteorite from an ancient asteroid, containing high levels of iron and nickel.

Holiday scams spike during Black Friday and Cyber Monday as criminals exploit your leaked personal data. Learn how to protect yourself from fake stores and phishing.

Commerce Department proposes TP-Link router ban over Chinese security risks. Learn how this potential prohibition could affect your home network and devices.

Hyundai AutoEver America suffered a data breach affecting 2,000 current and former employees, exposing names, Social Security numbers and driver's license information.

Washington court rules automated license plate reader images are public records, even when stored by vendors like Flock Safety, setting precedent for transparency.

Fake airline texts claiming flight cancellations are targeting travelers with convincing scams. Learn how cybercriminals steal personal data and credit card info.

Discover how iOS 26's new Adaptive Power feature automatically extends iPhone battery life by learning your usage patterns and adjusting performance intelligently.

New TikTok malware campaign tricks users into running PowerShell commands that download Aura Stealer, which steals credentials and authentication tokens.

Gaia Family offers fixed upfront pricing for IVF cycles with unlimited embryo transfers and financial protection, partnering with over 100 U.S. fertility clinics.

The Jetsons Act aims to position Pennsylvania as a leader in advanced air mobility by establishing regulations for hybrid ground-air vehicles.

Fructose Short-Circuits Glycolysis

Nutrition