Who says Fructose Promotes Obesity?
Written By: By David Liu, Ph.D.
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Published - May 22, 2011
Fructose has been associated with obesity. And many people believe now that fructose mostly in the form of high fructose corn syrup, which is commonly used in sugary drinks and processed foods, may be responsible for the obesity epidemic in the U.S.
But a Mexican study published in the May 27, 2011 issue of Metabolism suggests that was not the case when people used an energy restricted diet. Fructose used in such a diet actually helped obese people to lose weight.
For the study, M. Madero of Instituto Nacional de Cardiología Ignacio Chávez in Mexico City, Mexico and colleagues tested two energy restricted diets, one with a moderate amount of natural fructose (50 to 70 grams per day and the other with a low amount (less than 20 grams per day) in 131 obesity patients who had an average body mass index of 32.4 kg/m(2) at baseline.
Both diets had three different levels of energy, 1500, 1800, and 2000 calories per day.
Subjects were randomly picked to receive one diet or another. The dietary intervention lasted for six weeks. Weight loss in patients was calculated as the primary outcome and blood pressure, lipid profile, blood sugar, insulin resistance, uric acid, and others were measured as the secondary outcomes.
Patients in both energy restricted diets experienced a significant weight loss, compared to the weight at baseline. Both diets improved the secondary outcomes.
But more weight loss was observed in those who had the diet with the moderate amount of fructose, compared to those who had the low fructose intake, 4.19 pounds versus 2.83 pounds.
The researchers did not tell in the abstract of their study report how fructose intake affects weight loss in each energy level.
They concluded though that an energy-restricted diet with a moderate amount of natural fructose results in more weight loss than a low fructose energy restricted diet.
The results suggests that fructose alone does not boost the risk of obesity. The most important thing to do is use an energy or calorie- restricted diet.
That does not mean that high fructose corn syrup would have the same effect as natural fructose.
Rutgers University researchers have found reactive carbonyls in high fructose corn syrup, which are present at high levels in the blood of diabetes patients.