Research Suggests that to Lose Weight We May Have to Restrict Fructose

at 4:58 PM

First of all what is fructose? Fructose is an isomer of glucose and this simply means that their chemical structure is exactly the same except one variation in the three dimensional space.  Fructose naturally occurs in fruits and many vegetables.  But dietary exposure to fructose has increased over the past few decades and there is concern that high fructose consumption in humans may be in part responsible for the high incidence of obesity not just in the U.S but worldwide.  Certainly fructose is not the only cause of obesity but research suggests that since its metabolism is different than that of glucose it may be more lipogenic (making more body fat) than previously thought. 

In humans triglycerides (fat molecules) are primarily made in the liver.  As Dr. Elizabeth Parks from UT Southwestern in Dallas explains, the liver acts like a traffic cop to coordinate and decide what to do with the dietary sugars. Should it store it as glycogen, burn it for energy or turn it into fat?  Fructose, it seems, enters this pathway downstream and bypasses the traffic cop, so it may not be as tightly regulated as glucose.  Dr. Parks says that this less-controlled regulation may contribute to higher amounts of triglyceride synthesis.

As I mentioned before, fructose naturally occurs in fruit but it is added to many processed foods at high concentrations.  High fructose corn syrup is 55% fructose and 45% glucose.  It has become the preferred method of sweetening processed foods because it is cheaper, sweeter and easier to blend.

In Dr. Park's research they gave healthy lean subjects sugary drinks that were either 100% glucose, half and half glucose/fructose or 25% glucose/75% fructose.  They then measured fat synthesis in these individuals and they found that lipogenesis increased significantly when only half the glucose was replaced with fructose in the sugary drinks.  The fructose given in the sugary drinks to the subjects also changed the way the body handelled the food eaten at lunch.  So it was more likely that all the extra calories that the subjects consumed during lunch were turned into fat.

The subjects in this study were healthy, lean individuals and other studies suggest that fat synthesis may be worse in people who are overweight or obese. Obviously we can't demonize fructose, it is only one of the contributors to the whole complex problem of obesity.  Americans are eating too much of everything, too many calories, too much sugar, too much fat,  and little activity other than reaching for the remote.

These seemingly 'healthy' foods all contain high fructose corn syrup:

Yoplait yogurt

Most salad dressings especially the 'lite' or reduced calorie ones

Special K cereal- there is nothing smart about this cereal and please don't replace your lunch with it which is another favorite subject that I will tackle at another time!

Many of the low calorie ice cream treats

100 calorie snack packs are loaded with HFCS.  Just have a few almonds or sugar snap peas.