DIET CHAT USA

Are All Sugars Created Equal?

At the University of California, Davis, Dr. Peter Harvel conducted a study using 33 over-weight and obese adults to answer that question. These individuals were placed on a diet consisting of 30% fat, 55% complex carbohydrates and 15% protein for two weeks. For the following 10-weeks they switched to a diet where 25% of their energy came from either glucose or fructose.

Glucose is found in complex carbohydrates like grains and starch. Pure fructose is found in fruit juice, fresh fruit and preserves.

It has been feared for years that fructose and high fructose corn syrup (found in soft drinks and many processed foods) have been fueling the epidemic of obesity, stimulating insulin resistance and diabetes, but there have been few human investigations.

 

So, Peter Harvel conducted his study. Those in his study given fructose instead of glucose gained 1.5 kilograms and increased intra-abdominal fat—the fat that causes a pot belly and wraps itself around the internal organs and has been linked to increase the risk of cardiovascular disease and diabetes.

In comparison, the individuals who were given glucose instead of fructose gained the same amount of weight. However, the intra-abdominal fat did not occur.

This study was conducted using only pure fructose, but another study by Harvel and his colleagues, published in the American Journal of Clinical Nutrition (vol 87 p 1194) compared fructose, high fructose corn syrup, sucrose, and glucose. The participants consumed a meal containing 25% of the energy from fructose, sucrose, HFCS, or glucose.

The study found that blood triglyceride levels were raised in the individuals who consumed fructose, sucrose and high fructose corn syrup. Individuals who consumed glucose did not have elevated triglyceride levels, suggesting that fructose and fructose containing products may have the same effects on cardiovascular health and obesity.

Nevertheless, additional, long term studies need to be conducted to ascertain whether the high triglyceride levels produced by high fructose corn syrup and sucrose have similar effects to fructose on abdominal fat and insulin resistance. "The question is, what is the amount of HFCS or normal sugar you need to consume to get these effects?" says Havel, who is planning a long-term study to find out. He also says it's not too soon for people with metabolic syndrome - the combination of conditions including belly fat and insulin resistance that raise the risk of diabetes and cardiovascular disease - to avoid drinking too many fructose-containing foods and beverages.