June 9, 2004 -- All sweeteners may not be created equal when it comes to how they affect your weight.
New research suggests that fructose, a sweetener commonly used in soft drinks and found naturally in fruit juice, may induce a hormonal response in the body that promotes weight gain.
The study showed that drinking a fructose-sweetened beverage caused levels of the hormones insulin and leptin to be lower than those found after drinking a beverage sweetened with glucose, another natural sweetener.
Fructose also does not increase release of insulin and may lead to lower leptin levels. Thus, the researchers wanted to see if a high-fructose diet results in the same hormonal changes that result from a high-fat diet.
In addition, the study also showed that levels of another hormone called ghrelin, which is thought to stimulate appetite and normally declines after a meal, decreased less after drinking a fructose-sweetened beverage.
Fructose May Raise Obesity Risks
In the study, published in the Journal of Clinical Endocrinology and Metabolism, researchers fed 12 normal-weight women standardized meals containing the same number of calories and distribution of total carbohydrate, fat, and protein on two days. On one day the meal included a beverage containing fructose, and on the other day the same beverage was sweetened with an equal amount of glucose.
Researchers collected blood samples from the women after each meal and found several major differences in how the body responded to the two different sweeteners.
Following meals containing the fructose-sweetened beverage compared with the other:
- Leptin levels were lower (linked to increased appetite and weight gain) as were insulin levels.
- Levels of the appetite-triggering hormone ghrelin decreased less.
- Fatty molecules in the blood called triglycerides experienced a prolonged surge, which may raise the risk of heart disease.
Researchers say that taken together, the hormonal responses after drinking beverages containing fructose suggest that diets high in fructose may be one factor contributing to the current epidemic of obesity.
They estimate that fructose consumption has increased by 20%-30% over the last 30 years, a rate that is similar to the growth of obesity rates during the same period.
Even though fructose is found naturally in fruit juice, these findings would not likely apply to eating fruit. Other components of fruit, such as the fiber, would affect how the body handles fructose.
Researchers say more studies are needed to look at the long-term effects of fructose on appetite and energy.