New research shows that there are big differences in how the sugars fructose and glucose are metabolized by your body. Overweight study participants showed more evidence of insulin resistance and other risk factors for heart disease and diabetes when 25 percent of their calories came from fructose-sweetened beverages instead of glucose-sweetened beverages.
A study looked at 32 overweight or obese men and women. Over a 10-week period, they drank either glucose or fructose sweetened beverages totaling 25 percent of their daily calorie intake.
Both the groups gained weight during the trial, but imaging studies revealed that the fructose-consuming group gained more of the dangerous belly fat that has been linked to a higher risk for heart attack and stroke. The fructose group also had higher total cholesterol and LDL ("bad") cholesterol, and greater insulin resistance.
Dr. Mercola's Comments:
This is not the first study showing that fructose harms your body in ways glucose does not. Two years ago, another study
concluded that drinking high-fructose corn syrup (HFCS) -- the main ingredient in most soft drinks throughout the world -- increases your triglyceride levels and your LDL (bad) cholesterol.
And, just like this latest study, these harmful effects only occurred in the participants who drank fructose -- not glucose.
How Much Fructose are You Consuming?
Today, 55 percent of sweeteners used in food and beverage manufacturing are made from corn, and the number one source of calories in America is soda
, in the form of high fructose corn syrup.
Food and beverage manufacturers began switching their sweeteners from sucrose (table sugar) to corn syrup in the 1970s when they discovered that HFCS was not only far cheaper to make, it's also about 20 times sweeter than table sugar.
This switch drastically altered the average American diet.
Corn syrup is now found in every type of processed, pre-packaged food you can think of. In fact, the use of HFCS in the U.S. diet increased a staggering 10,673 percent between 1970 and 2005
, according to a recent report
by the USDA.
By USDA estimates, about one-quarter of the calories consumed by the average American is in the form of added sugars - the majority of which comes from high fructose corn syrup.
As I've mentioned on numerous occasions, processed foods account for more than 90 percent of the money Americans spend on their meals, so it's no wonder the yearly sugar consumption of the average American weighs in around 142 pounds a year
This is a staggering amount, but if you eat mainly processed foods, you're likely in this category whether you're consciously aware of consuming that much sugar or not.
Ironically, the very products that most people rely on to lose weight -- low-fat diet foods -- are often those that contain the most fructose!
My personal recommendation is to ideally limit your intake of added sugar to about 5 pounds per year in order to optimize your overall health, and one of the easiest ways to accomplish this is to focus on fresh, whole foods that have not been altered and processed.
Fructose is Metabolized Differently by Your Body
Despite the fact that this and other studies show clear differences in how fructose is metabolized by your body, researchers like principal investigator Peter J. Havel, PhD, and cardiologist James Rippe (who is also a consultant for the Corn Refiners Association), claim that the findings do not prove that HFCS is worse for your health than other sugars.
That simply makes no sense.
They keep claiming that HFCS is chemically similar to other widely used sweeteners, including table sugar (sucrose), honey, and even sweeteners made from concentrated fruit juices.
But this is clearly not true.
HFCS is a highly processed product that contains similar amounts of unbound fructose and glucose. Sucrose, on the other hand, is a larger sugar molecule that is metabolized into glucose and fructose in your intestine.
And whereas the glucose in other sugars are converted to blood glucose, fructose is a relatively unregulated source of fuel that your liver converts to fat and cholesterol.
There is over 35 years of hard empirical evidence, in addition to this latest study, showing refined man-made fructose like HFCS metabolizes to triglycerides and adipose tissue, not blood glucose.
The danger of that is that fructose does not stimulate your insulin
secretion, nor enhance leptin production, which is thought to be involved in appetite regulation. This was detailed in one of the most thorough scientific analyses
published to date on this topic.
Because insulin and leptin act as key signals in regulating how much food you eat, as well as your body weight, dietary fructose can also contribute to increased food intake and weight gain.
So, if you need to lose weight, fructose is one type of sugar you'll definitely want to avoid, particularly in the form of HFCS.
Beware of New Super-Charged Fructose Sweetener!
Despite the evidence against fructose, industry has created a new high-octane version of HFCS that's 99 percent fructose, called "crystalline fructose."
Clearly, all the health problems associated with HFCS could become even more pronounced with this product.
Adding insult to injury, crystalline fructose may also contain arsenic, lead, chloride and heavy metals
-- a virtual laundry list of toxic agents you clearly want to avoid at all cost. Especially if you have children, as all of these contaminants can impact your child's development and long-term health.
Fructose Raises Your Risk of Heart Disease
Aside from the weight gain and increased risk of diabetes, fructose has been shown to increase your triglyceride levels. In one previous study, eating fructose raised triglyceride levels by 32 percent in men.
Triglycerides, the chemical form of fat found in foods and in your body, are not something you want in excess amounts. Forty years worth of research has confirmed that elevated blood levels of triglycerides, known as hypertriglyceridemia, puts you at an increased risk of heart disease.
How to Have Your Cake and Eat it Too
Ideally I recommend that you avoid sugar, in all forms. This is especially important for people who are overweight or have diabetes, high cholesterol or high blood pressure.
But if you're looking for the occasional sweet treat, I recommend:
1. The herb stevia (this is the best and safest sweetener, although illegal to use as a food additive, according to the FDA)
2. Organic cane sugar
3. Raw, organic honey
I recommend avoiding all other types of sugar, including fructose, HFCS, and any type of artificial sweeteners. As I mentioned earlier, the absolute easiest way to do this is to stop drinking soda and avoid processed foods.
Small amounts of whole fruit, which do contain fructose, are typically not a problem. As long as you're healthy, feel free to enjoy fruit and berries in moderation according to your nutritional type.