what happens to excess glucose?


Have you ever wondered how ketosis actually works?

Why are carbs so bad when eaten in excess?

The process is simpler than you think, and when you understand the basics behind how your body stores and converts glucose, you'll gain a better understanding of the diet in its entirety.

What is Ketosis?

Believe it or not, the body experiences ketosis daily, wether you're following the keto diet or not (1). As you break down fats, your body creates molecules called ketones, and the body starts running off of these as its primary fuel source. Your body needs that fuel for energy, whether you're completing basic, everyday activities or high-powered workouts. This is where what you eat makes a difference, as the body will process whatever nutrients you put in it. A low-carb, high-fat diet speeds up ketosis, helping you gain more energy naturally. Both your body and brain function more efficiently on ketones rather than glucose, so kick starting ketosis benefits every single cell that you have (2-3).

When Does Ketosis Kick In?

It all starts with glucose. While glucose is needed to create ATP, a valuable energy molecule, your body doesn't need much (4). Your everyday diet will supply enough calories and nutrients for ample fuel, and because certain foods are broken down into glucose, your body will usually end up with an excess supply that isn't required. What happens to this supply? Well, the body has to break it down somehow. It does this through two main processes: glycogenesis and lipogenesis. Here are the basics:

Glycogenesis: During this process, your body's extra glucose is converted into glycogen. About half of your daily energy comes from glycogen, which is stored in the liver and muscles.

Lipogenesis: Your liver and muscles can only store so much, so once

their storage supplies get full, the excess glucose is converted into fat and stored away, resulting in weight gain.

These processes are vital to understanding ketosis because they not only demonstrate what happens to excess glucose, but what happens after, too. Once your body is out of glycogen, ketosis kicks in, and your body starts using its stored fat for fuel (5).

How Does Ketosis Work?

Ketosis naturally kicks in when the body has no access to food, whether you're fasting or sleeping. The ketogenic diet helps to keep you in ketosis all day (6). When fats are broken down further, they create fatty acids and glycerol.

Consider ketosis from an evolutionary perspective, our bodies run better on ketones because glucose wasn't always available (7). Without it, our ancient ancestors had no choice but to use stored fat for fuel, which is where ketosis began. Even without glucose, ancient bodies could hunt, gather, and go through everyday life on fat stores alone, so the body adapted over time, transforming ketosis into a natural process. We might not be hunting down wooly mammoths, but just like our ancestors, modern bodies can easily run off of fat stores.

The processes of glycogenesis and lipogenesis are ways of either storing glucose, or converting the glucose we no longer need into fat, helping our bodies function at their best. When you follow the ketogenic diet and maintain a regular state of ketosis, the body runs off of fat for fuel, weight gain isn't an issue, and a healthier lifestyle results (8).

When you understand how glucose is processed by the body, it makes dietary intake easier, too. While the science behind ketosis might sound difficult, it's surprisingly easy to comprehend. Just like our ancestors, who lived off stored fat, not glucose, ketosis is a healthy way of living--one the body has been accustomed to for thousands of years.

REFERENCES

(1) James Baggott, PhD. Synthesis and Utilization of Ketone Bodies. library.med.utah.edu. https://library.med.utah.edu/NetBiochem/FattyAcids/10_1.html. Accessed Sep. 23rd, 2018.

(2) Hussein M. DashtiNaji S. Al-ZaidThazhumpal C. Long Term Effects of Ketogenic Diet in Obese Subjects with High Cholesterol Level. Molecular and Cellular Biochemistry An International Journal for Chemical Biology in Health and DiseaseISSN: 0300-8177 (Print) 1573-4919 (Online). April 26th, 2006.

(3) Shelly Fan. The fat-fueled brain: unnatural or advantageous? blogs.scientificamerican.com. https://blogs.scientificamerican.com/mind-guest-blog/the-fat-fueled-brain-unnatural-or-advantageous/. Oct.1st, 2013. Accessed Sep. 23rd, 2018.

(4) Massimo Bonora, Simone Patergnani, Alessandro Rimessi, et al. ATP synthesis and storage. Purinergic Signal. 2012 Sep; 8(3): 343–357.Published online Apr 12th, 2012.

(5) Jørgen Jensen, Per Inge Rustad, Anders Jensen Kolnes, and Yu-Chiang Lai. The Role of Skeletal Muscle Glycogen Breakdown for Regulation of Insulin Sensitivity by Exercise. Front Physiol. 2011; 2: 112.Published online Dec 30th, 2011.

(6) Swink TD , Vining EP , Freeman JM. The ketogenic diet: 1997. Advances in Pediatrics [01 Jan 1997, 44:297-329] Jan. 1st, 1997.

(7) F. Luca, G.H. Perry, and A. Di Rienzo. Evolutionary Adaptations to Dietary Changes. Annu Rev Nutr. Author manuscript; available in PMC 2014 Sep 15.Published in final edited form as:Annu Rev Nutr. 2010 Aug 21; 30: 291–314. Aug. 21st, 2010.

(8) A Paoli, A Rubini, J S Volek, and K A Grimaldi. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr. 2013 Aug; 67(8): 789–796.Published online Jun 26th, 2013.

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