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Posts tagged ‘Fructose’

Sugar, the hidden enemy – part 2

In the last blog I talked about what sugar is, what it consist of, and how it is broken down in the body. I also mentioned that High Fructose Corn Syrup and sugar are basically the same thing, and that the difference between these two things and other carbohydrates is the molecule fructose. This fructose molecule and the way the body metabolizes it, may make it singularly harmful, at least if consumed in sufficient quantities(1-3).

They have done different studies on animals and have seen that if the fructose hits the liver in sufficient quantity and with sufficient speed, the liver will convert much of it to fat(4). This, according to the studies, will lead to a condition know as Insulin Resistance. So what is Insulin Resistance?

  • INSULIN RESISTANCE – When you eat something ( particular carbohydrates) your body responds by secreting insulin, to keep blood sugar in control after a meal. When your cell´s become resistant to insulin, your pancreas responds to rising blood sugar by pumping out more and more insulin. At the end your pancreas will no longer be able to keep up, this will lead to your blood sugar to rise out of control, and eventually you will probably get type 2 diabetes. Some people who are insulin resistance may NOT get diabetes, as somehow their body will continue to secrete enough insulin to overcome their cell´s resistance. But having elevated insulin levels is also quite bad, as it can lead to heart disease.

So basically the theory goes like this, accumulation of fat in the liver will lead to insulin resistance. You may ask yourself that maybe simply getting fatter leads to a fatty liver? But, this does not explain fatty liver in lean (skinny) people. According to Prof Lustig, the fat in the liver is caused by the fructose found in the SUGAR (5)!! Because the fructose component of sugar is metabolized primarily by the liver, while the glucose from sugar is metabolized by every cell in the body. So consuming sugar means more work for the liver. And this has been demonstrated in laboratory rats (6).  Whenever they wanted to create insulin resistance on them, they would just simply feed them diets consisting of pure fructose or sugar.

Now, I don´t want people to panic and think that fructose is horrible. Fructose is horrible if eaten in abundance. The dosages of fructose required to produce negative effects are quite high. Not impossible to reach through dietary means but almost impossible through fruit alone!!  I say this because, as most of us, know fruit is made up of fructose, and some people may think this is bad and the reason why they aren´t losing weight. But this is FALSE. What´s bad for you is the regular consumption of sugar sweetened beverages and all that sugary food we are always eating. Plus, fruit contains a lot of vitamins, minerals and other important nutrients, as well as fiber (7,8). Fiber helps slow your absorption of fructose. The slow absorption minimizes any surge in blood sugar(9).

So how much Fructose should you be eating? According to different clinical trials, 25-40 grams of fructose per day is totally safe. That´s 3-6 bananas, 6-10 cups of strawberries, or 2-3 apples per day(11). But for all those who drink a lot of sugar sweetened beverages or other ¨ junk food¨, I want to give an example so that you guys understand where the problem is really coming from(11).

  • A 20- ounce bottle of soda contains 35 grams of fructose (10,11)!!
  • If you eat a dessert with 50 grams of sugar – remember sugar is made up of 50% glucose, 50 % fructose – you are getting about 25 grams of fructose(11).
  • And let us not forget that HIGH FRUCTOSE CORN SYRUP is about 55% fructose, 45 % glucose, and this is found in many processed foods, fruit juices, sports-drinks, energy drinks and so on(11).

So now you tell me, where is the problem coming from? Why is sugar the hidden enemy? And how can we stop this obesity and diabetes epidemic?

Here is a link to a great video done by Prof. Lustig it has gotten 4 million views., it´s 1 hour and 20 minutes but it´s worth it.


  1. Wiernsperger N. Hepatic function and the cardiometabolic syndrome. Diabetes Metab Syndro Obes, 2013 Oct 10;6:379-88.
  2. Song M, Schuschke DA, Zhou Z, Chen T, Shi X Zhang J, Zhang X, Pierce WM jr, Johnson WT, Vos MB, McClain CJ. Modest fructose beverage intake causes liver injury and fat accumulation in marginal cooper deficient rats. Obesity (silver Spring). 2013 Aug:21(8):1669-75.
  3. Botezelli JD, Cambri LT, Ghezzi AC, Dalia RA, Voltarelli FA, de Mello Ma. Fructose-rich diet lead to reduced aerobic capacity and to liver injury in rats. Lipids Health Dis. 2012 Jun 19;11:78
  4. de Castro UG, Dos Santos RA, Silva ME, de LIma WG, Campagnole-Santos MJ, Alzamora AC. Age-dependent effects of high-fructose and hig-fat diets on lipid metabolism and lipid accumulation in liver and kidney of rats. Lipids Health Dis.2013 Sep18;12(1):136.
  5. Lustig RH. Fructose: It´s ¨alcohol without the buzz¨. Adv Nutr, 2013 Mar 1; 4(2):226-35.
  6. Lanaspa MA, Ishimoto T, Li N, Cicerchi C, Orlicky DJ, Ruzicky P, Rivard C, Inaba S, Roncal-Jimenez CA, Bales ES, Diggle CP, Asipu A, Petrash JM, Kosugi T, Maruyama S, Sanchez-Lozada LG, McManaman JL, Bonthron DT, Sautin YY, Johnson RJ. Endogenous fructose production and metabolism in the liver contributes to the developmetn of metabolic syndrome. Nat Commun.2013;4:2434
  7. Larsson SC, Virtamo J, Wolk A. Total and specific fruit and vegetable consumption and risk of strok3: a prospective study. Atherosclerosis, 2013 Mar; 227(1):147-52.
  8. Steinmetz KA, Potter JD. Vegetables, fruit, and cancer prevention: a review. J Am Diet Assoc.1996 Oct;96(10):1027-39.
  9. Ulrich IH, Albrin MJ. The effect of dietary fiber and other factors on insulin response: role in obesity. J Environ Pathol Toxicol Oncol.1985 Jul;5(6):137-55.
  10. Bray GA, Popkin BM. Calorie-sweetened beverages and fructose: what have we learned 10 years later. Pediatt Obes 2013 Aug;8(4):242-8.
  11. Matthew M. Do Fructose and Fruit Make You Fat and Unhealthy? www.muscleforlife. com April 15,2013.

Sugar, the hidden enemy!

As I have mentioned in other posts(, there has been a huge increase in obesity and diabetes in the last 50-60 years. It is such a huge problem that obesity is now a World Wide Epidemic, and recent studies are suggesting that a reason for this is the increase in amount of sugar we are eating. First, let´s explain what sugar is.

Sugar is not only the white granulated stuff that we put in coffee and sprinkle on cereal -which by the way is called sucrose- but also high-fructose corn syrup. High-fructose corn syrup replaced sugar in sodas and other products in the early 1980s, in part because refined sugar then had the reputation as generally noxious nutrient (meaning a bad nutrient). High-fructose corn syrup was portrayed by the food industry as a healthful alternative, and that is how the public perceived it. But recently this has started to change, companies have realized that high-fructore corn syrup was getting a bad rap and have decided to start using sugar again, saying that it is healthier, but is this true?

Well, according to professor Robert Lustig -a specialist on pedriatic hormone disorders and the leading expert in childhood obesity at the University of California- sugar and high fructose corn syrup are the same, meaning they are both bad, he even uses the word poisonous!

Refined sugar (that is sucrose) is made up of a molecule of the carbohydrate glucose, bonded to a molecule of the carbohydrate fructose, so it is 50-50. The fructose, which is almost twice as sweet as glucose, is what distinguishes sugar from other carbohydrate rich foods like bread or potatoes that break down upon digestion into glucose alone. High-fructose corn syrup is 55% fructose and 45% glucose. So you see, there isn´t really a big difference between sugar and high fructose corn syrup. Now let us get to the important  information and find out why both of them are quite bad.

  1. Refined sugar and high fructose corn syrup don´t come with any protein, vitamins, minerals, antioxidants or fiber, in other words they are basically empty calories.
  2. According to Prof Lustig ¨sugar has unique characteristics, specifically in the way the human body metabolizes the fructose in it¨. So let me give an example to explain things better. Imagine we eat 100 calories of glucose (from a potato or bread) or 100 calories of sugar (half glucose and half fructose). Those 100 calories which are the same will metabolize differently and have a different effect on the body, because the fructose component of sugar and high fructose corn syrup will primarily be metabolized by the liver, while the glucose from sugar and carbohydrates(potato, bread) will be metabolized by every cell in the body.
  3. They have done studies on animals and have seen that if the fructose hits the liver in sufficient quantity and sufficient speed, the liver will convert much of it to fat. When you take sugar in liquid form (sodas), the fructose reaches the liver faster. This apparently induces a condition know as insulin resistance, which is considered the fundamental problem in obesity, diabetes and heart disease.

Since I want you guys to stay with me I´m going to recap.

  • Sugar (sucrose) is 50% glucose and 50% fructose
  • High Fructose Corn Syrup (HFCS) is 45% glucose and 55% fructose.
  • Refined sugar and HFCS are basically empty calories.
  • The molecule of fructose found in sugar and HFCS is broken down by the liver. If the fructose hits the liver in sufficient quantity and with sufficient speed, the liver will convert much of it to fat. This apparently induces a condition know as INSULIN RESISTANCE.

I will leave it like that for the moment since there is a lot of information for you guys to absorb, but in my next post I will try to explain what insulin resistance is, why it leads to diabetes, and how all this is related to SUGAR.


Lustig RH. Fructose: It´s ¨alcohol without the buzz¨. Adv Nutr, 2013 Mar 1; 4(2):226-35.

BasuS, Yoffe P, Hills N, Lustig RH. The relationship of sugar to population-level diabetes prevalence: an econometri analysis of repeated cross sectional data. Plos One, 2013:8(2)

Weiss R, Bremer AA, Lustig RH. What is metabolic syndrome, and why are children getting it? Ann N Y Acad Scie, 2013 Apr; 1281:123-40.

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