Participants in the beverage interventions significantly reduced their intake of caloric beverages and increased their consumption of the recommended noncaloric beverages in a manner consistent with intervention assignment. The average daily reduction of caloric beverages across both of the beverage groups was approximately the 2-serving/d recommendation that was prescribed (eg, −235 kcal/d at 3 mo and −225 kcal/d by 6 mo). The AC group also reduced their caloric beverage consumption by ~1 serving/d (−112 kcal/d at 3 mo, −106 kcal/d at 6 mo), despite not being informed about the true study purpose or substitutions to that group or about the beverages being used as a weight-control strategy in the AC treatment sessions. Thus, we observed a smaller caloric difference between the 2 beverage substitution groups and the control group. All interventions groups showed statistically significant weight losses by 6 mo, but there were no differences between groups.
The DB group reported an absolute reduction in caloric beverage intake of ~70 kcal more per day at both 3 and 6 mo compared with the Water group, although reported reductions in energy (kcal) from food averaged over the 6 mo were very similar between the DB and Water groups. This reflected better adherence to the beverage replacement prescription in the DB group, which resulted in a greater likelihood of achieving a 5% weight loss compared with the AC group at 6 mo. The greater adherence to intake of DBs over time may have been due to the variety of flavors (36
) or similar properties to the caloric beverage (eg, caffeinated), which suggests that it may be easier for consumers of caloric beverages to replace their beverages with noncaloric sweetened alternatives. The pattern of weight loss in the Water group suggests a slower weight loss and may reflect that consumers of caloric beverages needed to adjust preferences for consuming nonsweetened beverages over time.
Despite similar or somewhat smaller weight losses, the water replacement groups showed statistically significant reductions in fasting glucose and improvements in hydration compared with the control AC group. The DB group also showed improvements in many of these variables by 6 mo, but the changes were not significantly different from those in the AC group. In the completer's analysis, the improvements in systolic and diastolic BP in the Water group were statistically significant from those in the AC group. Reductions in fasting glucose and BP seen in the Water group are similar to the improvements seen in other weight-loss trials at 6 mo (37
). These analyses should be interpreted with caution because the hydration-BP relation has not been well-studied and other mechanisms, other than the benefits of lowering body weight, are not clear (39
). Future analyses will examine potential diet, physical activity, and other mechanisms that might account for these changes.
The design of the current study differs from that of other studies in the literature, ie, previous research in adults focused on changes in beverage intake as part of overall dietary restrictions aimed to induce weight loss rather than on beverage replacement as the primary weight-loss strategy. Despite these differences, this study can be compared with others that examined the effects of beverage consumption during weight loss. In examining our findings on changes in caloric beverages overall, this study showed that a reduction in caloric beverages of ~2 servings resulted in a 2-kg weight loss at 6 mo across the DB and Water groups, which is more than the 0.6-kg weight loss that was associated with a 200-kcal/d reduction in liquid calories in a secondary data analysis of PREMIER. This study did not show as much of an advantage to an increase in water consumption as has been reported previously in the literature (13
). Participants in our study reported an increased consumption of water of 1 L/d at 3 mo and of ~0.80 L/d at 6 mo, yet they lost ~0.25% (or 0.3 kg) more than those in the AC group at 6 mo. Stookey et al (14
) reported a 2-kg greater weight loss among water consumers on a hypocaloric diet than among those who consumed less water, although participants in that study were not randomly assigned to consume more water. In the study by Dennis et al (24
), middle-aged adults on a hypocaloric diet were randomly assigned to consume 500 mL (~16 oz) of water 3 times/d, before each meal, or to follow the hypocaloric diet without premeal water consumption. Those randomly assigned to premeal water consumption lost ~1.3% more than did those on the hypocaloric diet alone (P
= 0.13). Future studies could examine whether the amount (eg, 1 compared with 1.5 L), the timing (premeal compared with not), or the other factors explain these differences. Notably, these prior studies included 8–29% nonwhite participants, whereas CHOICE included 60% nonwhite participants.
The results of this trial are encouraging despite the modest weight loss achieved. In more intensive clinic-based behavioral lifestyle modification programs (40
), 5–10% weight losses have been observed at 6 mo. This is not surprising because such programs typically include greater caloric restriction (500–1000 kcal/d), goals for caloric expenditure, more intensive diet and activity monitoring, and frequent patient-provider contact. This intervention required minimal self-monitoring (only beverages) and included monthly treatment visits with recommendations to change one aspect of dietary behavior and produced a 2–2.5% weight loss. The importance of caloric beverages as a target for calorie reduction is noteworthy because they are typically consumed at least daily, whereas food intake types may vary. This approach is more consistent with others recommending small but potentially sustainable lifestyle changes that can be made to improve health (43
The strengths of this study were that it is the first randomized trial in adults to examine a simple strategy for calorie reduction and weight control, with participants masked to the study purpose, including >50% racial and ethnic minorities, strong retention rates, 24-h dietary recalls, provision of beverages, an AC group, and objective weight and physiologic outcome measures. Importantly, the AC group was not a “no treatment control group”; this group was taught general weight-control strategies, reported weight and general behavior (not kcal) weekly, and attended 60-min monthly treatment meetings equating for contact time and other variables known to affect weight loss among motivated individuals. Limitations of the study included the potential for being underpowered, self-report measures of diet and physical activity, underrepresentation of men, a relatively short duration (6 mo) to allow benefit of a small caloric change such as beverage substitution to accrue, and lack of long-term follow-up.
On a population level, replacement of caloric beverages with noncaloric alternatives could be an important public health message. This strategy also has implications for health care settings because assessing SSB intake is feasible, and the prescriptive recommendation to replace caloric beverages with noncaloric alternatives is simple and straightforward. Replacing SSB with either DBs or water, based on the consumers’ preference and ability to adhere, appears warranted at this stage of research on the basis of these findings. Future research should examine long-term health effects of consuming either beverage as a replacement for caloric beverages before specific recommendations can be made.