Women who replaced an afternoon diet drink with water lost more weight and had better insulin sensitivity.
The study involved 81 overweight and obese women with type 2 diabetes who were all self-reported habitual consumers of diet drinks. Scientists asked them either to substitute water for diet drinks, or to continue drinking diet drinks five times a week after their lunch for 24 weeks.
Both groups of women were allowed to drink water at other times but were not allowed to have diet drinks at any other time. The two groups were also asked not to drink anything while eating their lunch and not to add low calorie sweeteners to drinks such as tea or coffee. The results are published in the journal Diabetes, Obesity, and Metabolism.
“Many obese people trying to lose weight believe that low calorie or diet drinks can help them to lose weight,” says Ian Macdonald, professor of metabolic physiology at the University of Nottingham. “This study shows that while they can still lose weight, they may not be losing as much as they would if they drank water in place of diet drinks.
“Our results also question whether consuming diet drinks is the most effective way for people with diabetes to manage their condition. But since the consumption of diet soda is higher among people with diabetes, the potential implications of our study needs further and larger scale research.”
The women followed a diet plan and their post-lunch drink option for 24 weeks with the goal of losing 7-10 percent of their body weight at a rate of 0.5 to 1 kilogram (about 1 to 2 pounds) a week. They also followed an exercise plan that gradually increased during the trial to achieve 60 minutes of moderate activity five days a week.
Body weight was measured at the start, at 12 weeks, and at 24 weeks. Waist circumference was also measured and BMI calculated at the same intervals. Fasting blood samples were collected also at the start, 12, and 24 weeks to check diabetes indicators.
“Our results are very interesting. They show that the women drinking water after their main meal at lunch time over 24 weeks lost on average 1.16 kilograms more than the women who drank diet drinks after their meal,” Hamid Farshchi from the University of Nottingham’s School of Life Sciences.
“We think that by drinking water instead of sweet-tasting diet drinks, the women may be adhering better to the weight loss diet because artificial sweeteners may increase desire for sweetened and more energy dense foods.
“We also found that the women who drank water achieved a better improvement in insulin sensitivity.”
Source: University of Nottingham