Study comparing the effects of drinking glucose- or fructose-sweetened drinks
I came across a 10-week study that compared the effects from drinking glucose- or fructose-sweetened drinks with interesting results. For the first two weeks of this study, 30 obese men and women consumed an energy-balanced diet, which is basically the amount calories required to maintain weight. These initial two weeks were conducted to help establish baseline measurements.
For the next 8 weeks, subjects were either given glucose- or fructose-sweetened drinks to have each day, which would account for 25% of their caloric needs. During this time, the subjects followed an self-selected ad libitum diet. That is, they could eat what they wanted, but the researchers had a fairly good idea how many calories they ate, on average, per day based on interviews. The subjects then consume either the glucose- or fructose-sweetened throughout the day in amounts, which would provide 25% of their caloric needs.
During the last two weeks of the study, subjects went back on an energy-balanced diet, but still consumed 25% of their caloric needs from either glucose- or fructose-sweetened drinks.
Throughout the study, the researchers looked at resting energy expenditure (REE) of the subjects. REE is the amount of calories (energy) required over a 24-hour period during a period of inactivity (like lying down). What they found was that those who consumed fructose-sweetened drinks had a significant decrease in REE. Whereas those who consumed glucose-sweetened drinks did not.
Additionally, the researchers looked at the net post-prandial (after food consumption) fat oxidation (burning) rates. What they found was that those who consumed the fructose-sweetened drinks had a significant decrease in fat oxidation when compared to their baseline measurements and the group who consumed glucose-sweetened beverages.
Furthermore, the researchers found that both groups gained fat without a significant difference between them. However, fat distribution was different. That is, those who consumed fructose-sweetened liquids primarily showed increases in visceral fat, which is the fat stored around the organs and is generally thought of as unhealthy. Whereas subjects consuming glucose showed more of an increase in subcutaneous fat, which is the fat underneath the skin and generally preferred over visceral fat.
Therefore, while the amount of fructose-sweetened drinks (such as fruit juice and soda/pop) consumed in this study seems relatively high, it would seem that large amounts of this type of drink are not beneficial.
For more information:
Cox, CL et al. 2012. Consumption of fructose-sweetened beverages for 10 weeks reduces net fat oxidation and energy expenditure in overweight/obese men and women. Eur J Clin Nutr. Feb; 66(2): 201–208.