Although I always encourage people to avoid artificial sweeteners, I want to stress the importance of avoiding a natural sweetener that, in some aspects, might even be worse. All of the following information is based on the work of Dr. Robert Lustig, Professor of Pediatrics in the Division of Endocrinology at the University of California, San Francisco. He is a pioneer in decoding sugar metabolism. For anyone who is interested in a more detailed report please watch his lecture here.
Fructose is one of the most commonly used sweeteners in the United States and has found its way into most of our foods. Used as high-fructose corn syrup (HFCS) in sodas, juices, and sport drinks, or grape juice extract, agaves sweetener, honey, or other fruit sweeteners in almost everything on our tables, fructose poses a major threat to our health. Child and infant obesity is an epidemic and Americans in general weigh 25 lbs more than 30 years ago. Associated diseases such as hypertension, heart disease, stroke, and diabetes all significantly increased despite the successful implementation of a low-fat diet since 1982 to battle obesity and heart disease. Much of this is a result of significant amounts of fructose added to our diets.
The average sugar consumption in the US has reached its peak at 141 lbs per person per year, with 63 lbs of that coming from fructose. The type of sugar our bodies utilize best is called glucose. It is our primary source of fuel and is used by every single cell in our bodies. Although over consumption of glucose certainly causes weight gain, obesity, and associated diseases, fructose is by far worse. And here is why:
- Fructose is a toxin that can only be metabolized by the liver and causes harmful effects to the body in this process. I order to metabolize it your liver produces VLDL (damaging form of cholesterol), triglycerides, and free fatty acids, which get stored as fat. It is interesting to note that the production of the damaging form of cholesterol (VLDL) is actually triggered by carbohydrates (e.g. fructose) and not by fat (triggers non-damaging form of cholesterol)
- Fructose increases uric acid levels which cause high blood pressure and gout. If your blood tests show elevated uric acid levels this might be why
- Fructose is converted into fat much more rapidly than glucose. When you eat 120 calories of glucose, less than one calorie is stored as fat. 120 calories of fructose results in 40 calories being stored as fat. Consuming fructose is like consuming fat
- Fructose causes us to eat more because it blocks the two hormones ghrelin and leptin which regulate our appetite and satiety, and it has a bad effect on our insulin regulation. Compared to 20 years ago, teen boys eat 275 kcal more per day, adult males 187 kcal, and adult females 335 kcal per day. Most of these calories (95%) come from carbohydrates not from fat (5%). We do not have more food available than 20 years ago. Our appetite regulating mechanisms just don’t work anymore.* And it’s primarily because of fructose
- Chronic fructose exposure leads to insulin resistance, metabolic syndrome, and increased belly fat
- It depletes important vitamins and minerals your body needs
- The more fructose you eat the more you will crave it
- Fructose and sucrose behave identically
You might ask why is there so much more fructose in our diets compared to 30 years ago? For this please watch the lecture by Dr. Lustig, MD.
*One more fact I found worth mentioning: Dr. Lustig points out repeatedly that, when it comes to weight gain and associated illness from fructose, it is not essentially about the calories but the biochemical processes fructose triggers in our bodies. While this is true it is important to understand why fructose makes us eat more.
Because our appetite and hunger regulating hormones leptin and ghrelin do not respond to fructose, ingesting calories from fructose will not make you feel less hungry or more satisfied and your brain will not even recognize that you have eaten. Therefore, if a person needs to ingest 2,500 kcal per day to function and 10% of those are from fructose they will essentially eat 250 calories more than they need. And if you consume one 12 oz can of soda (150 kcal) beyond what your daily caloric requirement is (every day, for one year) you will gain 15,6 lbs of fat per year. According to Dr. Lustig this makes the obese the victim, especially when it comes to child obesity. I have to agree.
So remember, it’s not in the fats! If you want to be healthy, avoid those types of sweeteners. The best is to avoid sugar in general. If have seen many people who lost excess weight very fast simply by cutting out processed foods, sugar and breads and by consuming a diet of mostly based on vegetables and lean protein.