We have been talking about artificial sweeteners for the past fews weeks as a substitute for sugar and it has sparked a lot of controversy. There is a lot of belief that natural is always a better option no matter what.

Especially in the wake of the grossly inaccurate documentary “What The Health?”, that absolves sugar from all wrongdoing, I thought I would focus this week’s RADLAB article on the dangers of over-consuming sugar and why a sugar substitute isn’t the worst thing in the world.

Artificial sweeteners may not be the healthiest compounds you put in your body, but when it comes to copious amounts of added sugar, sugar is documented to be directly tied to a greater number of diseases with greater severities.

So if you’re curious about the bitter truth about sugar and it’s impacts on our health, then you need to read this article...


Added Sugar Is Unnatural

Just because something is unnatural, doesn’t necessarily make it bad for you, but for all those who think sugar is better for them simply because it’s natural, think again.

Let me start by saying there is nothing natural about how sugar has been added to the entire food industry. In its natural form, sugar is almost always coupled with fiber. Fruit is certainly sweet, but the inclusion of fiber is what allows the body to metabolize it in a healthy fashion. Even sugar cane itself has so much fiber it’s literally a stick.

Eating whole foods that contain natural sugars is not at all the problem. Our bodies evolved to process sugar in this combination. The real problem exists when refined sugar is added to food items, because in this case, it is not accompanied by its corresponding fiber. Make no mistake, the added sugar in the food industry is at the epicenter of many metabolic diseases of today.

How Much Sugar Are You Really Eating?

In moderation sugar is ok, but the overconsumption of sugar is that overwhelms the body and drastically affects your metabolism on many fronts. The major issue is that you may underestimate how much added sugar is already in your diet before you even consider sugary sweets. Of the over 600,000 items in the american food supply, 80% of them have added sugar. Things like bread, yogurt, juice, salad dressing, bbq sauce, spaghetti sauce...and much more, all typically have a ton of added sugar. So while you think that rationing your sugar consumption, from things like sweets, it’s likely that you’re consuming more added sugar than you intend.

Aren’t Sugars And Carbohydrates The Same?

When I was in high school learning about carbohydrates in science class I didn’t think there was anything to worry about sugar, since it’s just a regular natural carbohydrate that fuels my body. I know carbohydrates are good, so sugar shouldn’t be bad. Since then I have learned that I couldn’t be further from the truth.

Yet even today, most people don’t quite fully understand the dangers associated with excessive added sugar consumption. This is because when they think of sugar, their mind automatically assumes the broader picture of all carbohydrates. However, the truth is that not all carbohydrates are equal, and consequently, your body treats them vastly differently.

For example, you may notice that not all carbohydrates are sweet. Starches are not sweet. Surprisingly, even the breakdown product of starch, glucose, isn’t very sweet. I originally found this surprising because I thought all carbohydrates eventually broke down to glucose in the end. The reason that table sugar is sweet, has nothing to do with the glucose at all, and in fact glucose is not the enemy.

Glucose: The Energy of Life

Glucose is a perfectly healthy energy source that can be used in any tissue in the body. Every living organism on the planet can metabolize glucose for energy. The consumption of complex carbohydrates, maltodextrin or even straight dextrose ultimately enters the bloodstream as glucose. Since it can be used by every tissue, it gets spread around the body and never overwhelms any single organ. Muscle for instance is a huge recipient of glucose. During exercise, glucose is the primary and most efficient source of energy, and during rest, muscle can stockpile added glucose as glycogen. Consequently, less than 20% of the total glucose load makes it to the liver to be metabolized, where the liver also has a great ability to store glucose as glycogen. Some glucose will be burned as energy to fuel the liver, and a small portion of it will be converted to fat, packaged as VLDL cholesterol, which eventually finds its way to a fat cell. For the most part, however, glucose is not responsible for producing fat in the liver or causing most other metabolic diseases.

Unfortunately, the glucose molecule isn’t very sweet and thus is not what is added to foods to improve palatability. The molecule that possesses sweetness is something completely separate, called fructose and, fructose is the prime reason why sugar is so bad.

Table sugar (sucrose) is a sugar molecule that as soon as it hits your mouth breaks into two parts: One part glucose and one part fructose. While the glucose poses very little health risk, any appreciable amount of fructose is what is wreaking havoc on your metabolism.

High-fructose corn syrup (HFCS), is simply the combination of glucose and fructose that is already separated from each other, and as you can imagine, is treated in a similar fashion as sucrose.


The Dangers of Fructose Metabolism In Your Liver

Unlike glucose, that uses a transporter found all around the body, called GLUT2, fructose requires a different transporter called GLUT5, that is nearly exclusively located on the liver. This means that nearly all dietary fructose needs to go straight to the liver to be metabolized and cannot be spread throughout the body as glucose is.

This is the first reason why fructose is so different. A diet high in added sugar does not fuel most of the body but instead completely overwhelms a single organ: the liver.

Once inside the liver, a common misbelief is that fructose can be converted directly into the non-toxic, glucose. Unfortunately, this is never the case. In some cases, with elite athletes for example, when liver glycogen has been completed depleted, fructose can be converted to glycogen and stored in the liver for future use. However, there is a limited capacity to store fructose as glycogen and when that limit is reached, fructose metabolites directly activate enzymes responsible for new fat formation. It is definitively incorrect to believe that fructose will enter the liver, simply be converted to glucose and proceed to leave the liver to fuel other tissues.

Unless, you’re an elite athlete that has depleted your liver glycogen, more than 30% of the ingested fructose will directly end up as fat. For this reason, a diet high in sugar, can also be considered a diet high in fat because a lot of the sugar will be immediately converted to fat anyway. A lof of this fat production will be targeted to the fat cells, but some of this fat will not even make it out and instead stay in the liver to contribute to fatty liver disease.


Fructose Alters Metabolic Biochemistry

Converting fructose directly to fat is a major concern, for fat gain and the development of obesity and liver steatosis, it is not the only health consequence of fructose.

Blood pressure

One of the very first steps in fructose metabolism in the liver increases the production of uric acid. In extreme cases, this can then lead to gout. However, uric acid also plays a role in inhibiting an enzyme responsible for keeping blood pressure low, nitric oxide synthase. Therefore excessive sugar can be responsible for increasing blood pressure, but this is not the only mechanism responsible for high blood pressure.


People are quick to point out that fructose can’t cause diabetes because fructose does not stimulate an insulin response. The latter part is true; fructose does not stimulate insulin, at least not very effectively. However, that’s only half the problem fructose has with insulin. The metabolites of fructose in the liver have been shown to inhibit insulin signaling, which leads to liver insulin resistance. This makes the pancreas work much harder to produce higher insulin levels, which further raises blood pressure, increases fatty acid synthesis in the body, and increases fatty acids delivery into the fat cells. Effectively, the implication on insulin signaling is another mechanism that fructose leads to fat gain, but more importantly insulin resistance and inevitably diabetes.

Additionally, high-insulin levels and insulin resistance is directly linked to leptin resistance which promotes a whole host of additional metabolic issues that can be discussed in another post. In short, the negative effect on leptin promotes continued caloric consumption because your brain loses the ability recognize that energy was consumed. Ultimately, through its effect on insulin and subsequently leptin, the fructose in added sugar consumption ends up telling your brain that you're starving, which then leads to overeating.
Overall, the impact that fructose has on insulin signaling, negatively affects high blood pressure, fat production, fat storage, insulin resistance, and leptin resistance, which subsequently contributes to overeating and a lack of energy toward exercise.


Sugar in the bloodstream is directly involved in a reaction (called the Maillard reaction) that negatively affects the proteins it comes in contact with. The effects of this reaction over time is responsible for several of the effects of aging. The reaction consists of sugar molecules attaching to proteins (glycation) causing them to have decreased function, decreased flexibility and resulting in the release of reactive oxygen species. In a diet insufficient with anti-oxidants, this can lead to oxidative stress and the damage to several body systems.The glycation products from the Maillard reaction affect nearly every type of cell and molecule in the body and are a factor in aging and in the development or worsening of many degenerative diseases.

This reaction is continuously occurring and aging is something we cannot prevent. However, this reaction occurs seven times faster with fructose than it does with glucose, suggesting that those with a high-sugar diet will potentially age faster than individuals who restrict added dietary sugar.

The functional outcome with the production of these glycation products not only include oxidative stress, but also inflammation associated with many metabolic diseases. They also get linked into blood vessels that cause stiffening, again raising blood pressure, and the entrapment of LDL cholesterol, associated with heart disease. Additionally, the glycation of LDL cholesterol by fructose has been shown to accelerate the progression of atherosclerosis. Therefore, there is substantial evidence that a diet chronically high in added sugars are accelerating the aging process.


Sugar: Just as Harmful to The Liver as Alcohol

Sugar, particularly the fructose in sugar meets all the defining characteristics to be considered a poison. Sugar is not simply just empty calories but rather a harmful compound that is essentially no different than alcohol is in the liver. As a matter of fact, the alcohol molecule (ethanol) is literally fermented sugar and the parallels between ethanol and fructose are uncanny. They have the same chronic outcomes because they both go through very similar reactions to increase uric acid, increase blood pressure, produce extra fat, contribute to obesity and destroy the liver. The damage to the liver is very well-accepted with alcohol but some people still don’t appreciate the connection with sugar.

Obviously, these disease states only manifest when you over-consume these products. I’m not advocating to cut out sugar completely from your diet, just as I do not suggest everyone needs to cut out alcohol completely. There is nothing wrong with living a balanced lifestyle while accepting that everything we do is not always perfectly healthy. The human liver can handle a lot of toxins and poisons through our lives, but let’s not kid ourselves and believe that sugar isn’t a chronic hepatotoxin that is harmful to your health in high amounts. It certainly is not part of a natural diet that some people believe.


In moderation, the negative effects of added sugar in our food and beverages are minimal. Just as we are cautious with many other vices in our lives, sugar is something to be cognisant of. The notion that sugar is a natural carbohydrate and therefore must have no harmful effects is simply a naive view of the many ways that added sugar can impact your health in a negative way.

Studies designed to determine causation, have shown sugar to be causal to diabetes, heart disease, fatty liver disease and tooth decay. Sugar is certainly not the only cause of diabetes however, 25% of diabetes worldwide is explained by sugar alone. In fact, one study determined that only changes in sugar availability has been shown to the prevalence of diabetes.

An important point from this article is that the mechanisms for these diseases are not completely tied to glycemic index, or even total calories, as fructose and sucrose both have fairly low glycemic indexes. The critical idea of this article is that fructose is toxic to the liver all by itself, independent of the calories. The severity of these effects are a relationship the volume of added sugar being consumed on a regular basis. Simply put, excessive fructose consumption puts fat in your liver, makes your pancreas release more insulin and that causes diabetes and ultimately metabolic syndrome.
In order to avoid these negative effects here are a few tips to consider:

Eat mostly whole food with low sugar and high fiber.
Eat food with added sugar in moderation. The american health associated recommends ingesting no more than 25g of added sugar for woman or 38 g of added sugar for men.
When eating particularly sugary food, include other fibre sources to reduce the effects of sugar. Studies show that eating fruit with fruit juice is actually healthier than drinking fruit juice on its own despite having more total sugar.

Bottom line is you can definitely still enjoy some sugary foods or beverages every once in awhile as part of a balanced, sustainable diet, but don’t think that because sugar is naturally found in certain foods that it automatically makes it healthy for you in mass quantities.

Be sure to keep things in moderation and opt for less added sugars when an alternative is available. The use of artificial sweeteners can be an effective method to satisfy your sweet cravings without the onslaught of metabolic consequences. For more information on the health effects of artificial sweeteners, you can check out this previous RADLAB article here.

If you’re someone who regularly enjoys sugary beverages like juice, lemonade or soda, a great alternative would be AminoFast™ by Blue Star Nutraceuticals™. At Blue Star Nutraceuticals we never formulate our products with added sugars (even those with carbohydrates).

With AminoFast™ you get all the sweetness of a sugary drink without the sugar plus the added benefits of a full dose of BCAAs and glutamine to help prevent muscle breakdown and reduce soreness.

Find out more about AminoFast™ and try it out for yourself on the next page:

Next Page


  1. Bizeau ME, Pagliassotti MJ. Hepatic adaptations to sucrose and fructose. Metabolism. 54; 1189-1201, 2005.
  2. Choi HK, Curhan G. Soft drinks, fructose consumption, and the risk of gout in men: prospective cohort study. BMJ. 336; 309-312, 2008.
  3. Dills WL. Protein fructosylation; Fructose and the Maillard reaction. Am J Clin Nutr. 58; 779S-787S, 1993.
  4. Elliott SS, Keim NL, Stern JS, Teff K, Havel PJ. Fructose, weight gain, and the insulin resistance syndrome. Am J Clin Nutr. 76; 911-922, 2002.
  5. Faeh D, Minehira K, Schwarz JM, Periasamy R, Park S, Tappy L. Effect of fructose overfeeding and fish oil administration on hepatic de novo lipogenesis and insulin sensitivity in healthy men. Diabetes. 54; 1907-1913, 2005.
  6. Gao XB, Qi L, Qiao N, Choi HK, Curhan G, Tucker KL, Ascherio A. Intake of added sugar and sugar-sweetened drink and serum uric acid concentration in US men and women. Hypertension. 50; 306-312, 2007.
  7. Havel PJ. Dietary fructose: Implications for dysregulation of energy homeostasis and lipid/carbohydrate metabolism. Nutr Rev. 63; 133-157, 2005.
  8. Hellerstein MK, Schwarz JM, Neese RA. Regulation of hepatic de novo lipogenesis in humans. Annu Rev Nutr. 16; 523-557, 1996.
  9. Johnson RJ, Segal MS, Sautin Y, Nakagawa T, Feig DI, Kang DH, Gersch MS, Benner S, Sanchez-Lozada LG. Potential role of sugar (fructose) in the epidemic of hypertension, obesity and the metabolic syndrome, diabetes, kidney disease, and cardiovascular disease. Am J Clin Nutr. 86; 899-906, 2007.
  10. Johnson RK, Appel L, Brands M, Howard B, Lefevre M, Lustig R, Sacks F, Steffen L, Wyllie-Rosett J. Dietary sugars intake and cardiovascular health: a scientific statement from the American Heart Association. Circulation. 120; 1011-1020, 2009.
  11. Kelley GL, Allan G, Azhar S. High dietary fructose induces a hepatic stress response resulting in cholesterol and lipid dysregulation. Endocrinology. 145; 548-555, 2004.
  12. Le KA, Ith M, Kreis R, Faeh D, Bortolotti M, Tran C, Boesch C, Tappy L. Fructose overconsumption causes dyslipidemia and ectopic lipid deposition in healthy subjects with and without a family history of type 2 diabetes. Am J Clin Nutr. 89; 1760-1765, 2009.
  13. Lustig RH. Response to “Metabolic improvement with fructose restriction: Is it the fructose or the weight loss?”. Obesity. 24; 550, 2016.
  14. Lustig RH, Mulligan K, Noworolski SM, Tai VW, Wen MJ, Erkin-Cakmak A, Gugliucci A, Schwarz JM. Isocaloric fructose restriction and metabolic improvement in children with obesity and metabolic syndrome. Obesity. 24; 453-460, 2016.
  15. Lustig RH. Fructose: metabolic, hedonic, and societal parallels with ethanol. J Am Diet Assoc. 110; 1307-1321, 2010.
  16. Montonen J, Jarvinen R, Knekt P, Heliovaara M, Reunanen A. Consumption of sweetened beverages and intakes of fructose and glucose predict type 2 diabetes occurrence. J Nutr. 137; 1447-1454, 2007.
  17. Ng SW, Slining MM, Popkin BM. Use of caloric and noncaloric sweeteners in US consumer packaged foods, 2009-2009. J Acad Nutr Diet. 112; 1828-1834, 2012.
  18. Nguyen S, Choi HK, Lustig RH, Hsu CY. Sugar-sweetened beverages, serum uric acid, and blood pressure in adolescents. J Pediatr. 154; 807-813, 2009.
  19. Pickens MK, Yan JS, Ng RK, Ogata H, Grenert JP, Beysen C, Turner SM, Maher JJ. Dietary sucrose is essential to the development of liver injury in the MCD model of steatohepatitis. J Lipid Res. 50; 2072-2082, 2009.
  20. Rodriguez LA, Madsen KA, Cotterman C, Lustig RH. Added sugar intake and metabolic syndrome in US adolescents: cross-sectional analysis of the National Health and Nutrition Examination Survey 2005-2012. Public Health Nutr. 19; 2424-2434, 2016.
  21. Rutledge AC, Adeli K. Fructose and the metabolic syndrome: Pathophysiology and molecular mechanisms. Nutr Rev. 65; S13-S23, 2007.
  22. Basu S, Yoffe P, Hills N, Lustig RH. The Relationship of Sugar to Population-Level Diabetes Prevalence: An Econometric Analysis of Repeated Cross Sectional Data. PLoS ONE 8; e57873, 2013.
  23. Schalkwijk CG, Stehouwer CD, van Hinsbergh VW. Fructose-mediated non-enzymatic glycation: Sweet coupling or bad modification. Diabetes Metab Res. 20; 369-382, 2004.
  24. Schwarz JM, Noworolski SM, Wen MJ, Dyachenko A, Prior JL, Weinberg ME, Herraiz LA, Tai VW, Bergeron N, Bersot TP, Rao MN, Schambelan M, Mulligan K. Effect of High-Fructose Weight-Maintaining Diet on Lipogenesis and Liver Fat. J Clin Endocrinol Metab. 100; 2434-2442, 2015.
  25. Shapiro A, Mu W, Roncal C, Cheng K, Johnson RH, Scarpace PJ. Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding. Am J Physiol Regul Integr Comp Physiol. 295; R1370-1375, 2008.
  26. Sorensen BL, Raben Am Stender Sm Astrup A. Effect of sucrose on inflammatory markers in overweight humans. Am J Clin Nutr 82; 4221-427, 2005.