Alternative Eats Part II Addendum
Covering two new studies on artificial sweeteners and weight-loss
In a recent post, I broke down the randomized-controlled trials (RCTs) included in the World Health Organization’s latest guidelines on the use of non-sugar sweeteners (NSS ; i.e. artificial sweeteners) for weight-control. (I)
In the process, I found that the vast majority (>85% of the 32 studies) are not properly designed to assess whether NSS are useful for weight-management in the context of a realistic weight-loss or weight-loss maintenance protocol.
In particular, they didn’t meet my criteria of being mid- (2-6 months) to long-term (6 months+) in duration and including an intentional weight-loss or weight-loss maintenance protocol involving NSS-use or substitution for caloric sweeteners (i.e. added sugar).
Amongst the 7 studies from that meta-analysis that did meet these criteria (VII, VIII, XII, XIII, XIV, XV, XVI), I found that the results suggest that NSS-use is an effective tool for weight management.
In addition to those 7 studies, Harrold et al. recently published two papers that both meet our criteria. The first one consists of a 12-week weight-loss protocol (IX), while the second covers a follow-on 40-week weight-loss maintenance protocol in the same subjects from the first study. (X)
Importantly, since these were just published in August and October of 2023, they are not included in any of the reviews or meta-analyses on NSS and weight-management that I have seen to date—including the meta-analysis at the basis of the World Health Organization’s new guidelines. (II, III, IV, V, VI)
Here, we’ll breakdown these studies and what they mean for answering our question of whether artificial sweeteners are useful for weight management.
If you’re interested in learning more about artificial sweeteners and weight-management as a whole, start here.
Origins
Harrold and colleagues based their, “The effectS of non-nutritive sWeetened beverages on appetITe during aCtive weigHt loss” (SWITCH) studies off of a similar pair of studies published by Peters et al. in 2014 and 2015. (VII, VIII)
The original pair had overweight and obese subjects aged 21-65 follow a cognitive behavioral therapy weight-loss protocol. Notably, all of these subjects regularly consumed at least 3 non-nutritive-sweetened beverages (NNS; i.e. artificially-sweetened beverages) per week prior to entering the study. (VII, VIII)
On top of their weekly weight-loss meetings, the subjects consumed 24 ounces of either NNS beverages or water per day. The first phase consisted of 12 weeks of active weight-loss, while the second phase involved 40 weeks of weight-loss maintenance.
At the close of the first study, the subjects in the NNS group lost statistically significantly more weight on average than subjects in the water group (13.1 lbs vs. 9.0 lbs, respectively). (VII) Also, 64.3% of the subjects in the NNS group lost greater than 5% of their body weight as compared to 43% of the subjects in the water group. (VII)
This gap widened by the end of Phase 2, where subjects who completed both phases in the NNS group lost 18.5 lbs relative to their baseline weight as compared to the water group’s 7.5 lbs of weight-loss relative to baseline. (VIII) The portion of subjects achieving greater than 5% weight-loss also remained in favor of NNS-use, with 44.2% of subjects in the NNS group succeeding compared to 25.5% in the water group. (VIII)
Take Two
Harrold and colleagues sought to replicate these studies while addressing a couple of limitations. Specifically, they were interested in what would happen if the subjects voluntarily continued consuming the beverages for another year following the maintenance phase but without any cognitive behavioral therapy weight-control meetings or guidance. (IX)
Also, they wanted to test whether they would find similar results if they included subjects who did not regularly consume NNS beverages (remember, the subjects in Peters et al.’s studies all consumed at least 3 NNS beverages per week prior to entering the study). (IX)
“The SWITCH trial built on [the Peters et al. studies] by including an additional voluntary 1-year extension to assess effects during unassisted weight maintenance as well as by including both NNS beverage-naïve and non-naïve participants.” (IX)
Aside from including, “NNS beverage-naïve,” subjects–defined as individuals for whom 0-25% of drinks in the past 5 years were NNS beverages–and involving only people living near Merseyside, England, this second round of studies utilized similar inclusion criteria as those used by Peters and colleagues (IX, X):
Healthy males and females
Aged 18-65
BMI 27-35 (overweight/obese)
Regularly consume more than 3 chilled beverages of any type per week
Harrold and colleagues also used a similar intervention scheme, where subjects in each group attended weekly cognitive behavioral therapy sessions with nutritionists and consumed at least 2 servings of either NNS beverages or water each day. (IX, X)
“The 12-week active weight-loss phase was based on the comprehensive cognitive behavioral intervention ‘The Colorado Weigh’ [(25)], used by the [Peters et al.] group [(23)]. The program consisted of weekly 1-hour group meetings (5–20 participants) led by a qualified nutritionist who provided guidance on nutrition, behavioral changes, and structured physical activity, as well as homework for participants to complete prior to their next session.” (IX)
At the end of Phase 1 (active weight-loss), subjects in both groups lost a significant amount of weight–12.8 lbs and 12.3 lbs for the NNS and water groups, respectively–with no statistically significant difference between the two groups in terms of weight-loss. (IX)
Phase 2 (weight-loss maintenance) showed similar results, in that both groups lost a significant amount of weight relative to baseline on average. (X)
However, at the 1-year mark, subjects in the NNS group lost statistically significantly more weight relative to baseline on average than subjects in the water group did on average (16.5 lbs vs. 13.4 lbs, respectively). (X)
Of note, although this ~3 lbs difference was statistically significant, the authors deemed it clinically insignificant. In other words, although the statistical analysis suggests that this difference did not simply occur due to chance, the authors think the difference is too small to make a meaningful impact in real-life (i.e. 13 lbs of weight-loss on average is basically as good as 16 lbs of weight-loss on average)
“Although the difference in weight loss between the groups was statistically significant, it is important to note that this did not reach the 1.5-kg difference identified for clinical significance [15]. The results were statistically significant because the small increase in power compared with the protocol meant that this difference between the groups could be observed.” (X)
For more details on the importance of statistical vs. clinical significance, check out this post.
Interestingly, both groups made similarly large reductions in sugar consumption and did not experience increased hunger at the end of either phase. (IX, X)
The NNS group did show a statistically significant greater decrease in hunger on average at Week 12 relative to baseline. (IX), while the water group did show a non-statistically significant greater decrease in hunger rating on average at the end of the maintenance phase. (X)
But neither of these differences were statistically significant when comparing between the groups. (IX, X)
Conclusions
So, what does this mean from a zoomed-out perspective?
To me, first, this is another pair of studies to add to our list of mid- to long-term weight-loss/weight-maintenance RCTs suggesting that artificial sweetener-use is an effective tool for facilitating weight-loss. (VII, VIII, XII, XIII, XIV, XV, XVI)
Second, this is another case where both AS- and water-use showed benefits in the context of weight-loss/weight-maintenance protocols. (VII, VIII, XII, XIV, XVI)
Importantly, it’s also another example that AS-use showed benefits despite not showing any clinically significant differences compared to water–i.e. just because it isn’t better than water doesn’t mean it isn’t useful at all.
For more details on my first and second points here, check out this post.
Thirdly, if we simplify things, this is another well-designed RCT suggesting that artificial sweeteners are essentially the same as water from a calorie standpoint when it comes to weight-management. This is important because it refutes the claims that consuming artificial sweeteners will cause you to gain weight.
Lastly, as I’ve repeated and will continue to repeat, it’s also an example that you don’t need to use artificial sweeteners to lose weight: you can cut calories without them—using water to help you, for example—and do just fine with weight-management as well.
IMPORTANT: If you enjoyed or found this post useful, leave a like and/or a comment to let me know what you think. This will help me gear future content towards what’s best for you. Thanks again for reading/listening.