A claim you hear on longevity podcasts

Do diet sodas help you lose weight?

The claim checked: Swapping sugary drinks for diet drinks may help weight loss, though the trials are not clear-cut Hear it at 25:30

What do the studies say?

Leaning for

Six of ten studies found that diet drinks or other low-calorie sweeteners in place of sugar help with weight. A pooled analysis adds up many smaller studies; one of 15 trials found the swap modestly cut body weight. A review found that replacing sugary drinks with diet drinks or water cut BMI by about 0.3 units over 6 to 18 months. One Dutch study of 78,286 adults went the other way: people who made the swap gained slightly more weight. Three studies were mixed, including two trials where the diet-drink group lost no more weight than the others.

Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.

What was said on the podcast?

“You know, there's some evidence that if you replace habitual sweetened beverage consumption with habitual artificial sweetened beverage consumption, that that could have some beneficial effects on weight loss.”

Scott Kanoski, a guest on Huberman Lab · How Food Choices Shape Memory, Cognition & Cravings | Dr. Scott Kanoski · 25:30 on YouTube

Episode check Most people quit GLP-1 drugs within two years, the episode says. Nine studies split on it. 4 claims checked against 50 studies · 29 chapters not checked yet See the whole episode →

Point 1 of 2 Leaning for

Replacing sugar-sweetened drinks with artificially sweetened drinks helps people lose weight

Agree 6

pooled analysis · 2016 · landmark

“We found a considerable weight of evidence in favour of consumption of LES in place of sugar as helpful in reducing relative EI and BW, with no evidence from the many acute and sustained intervention studies in humans that LES increase EI.”

Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies. Int J Obes (Lond)
Who: Systematic review of animal studies, prospective cohorts and human intervention studies; the main BW meta-analysis of sustained trials covered adults (mostly overweight or obese) and one trial in children
PMID 26365102

systematic review · 2022 · landmark

“In this systematic review and meta-analysis, using LNCSBs as an intended substitute for SSBs appeared to be associated with reductions in body weight and cardiometabolic risk factors, including BMI, percentage of body fat, and IHCL, without evidence of harm.”

Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk: A Systematic Review and Meta-analysis. JAMA Netw Open
Who: 1,733 adults with overweight or obesity who were at risk for or had diabetes, in 17 RCTs (mean age 33.1 years, 77.4% women)
PMID 35285920

pooled analysis · 2014

“Findings from the meta-analysis of 15 RCTs—the gold standard study design in medical research—indicate that substituting LCS for sugar modestly reduces body weight, BMI, fat mass, and waist circumference.”

Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies. Am J Clin Nutr
Who: Generally healthy children and adults in 15 RCTs (8 solely in overweight or obese populations) and 9 prospective cohorts
PMID 24944060

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pooled analysis · 2020

“Rather, our data indicate that replacing sugar with NNS leads to weight reduction, an effect that is particularly evident in adults, subjects with overweight/obesity, and those under an unrestricted diet.”

Effects of nonnutritive sweeteners on body weight and BMI in diverse clinical contexts: Systematic review and meta-analysis. Obes Rev
Who: RCTs in children/adolescents and adults with normal weight, overweight or obesity, without diabetes, pregnancy or other chronic disease
PMID 32216045

systematic review · 2021

“The results of this review show that consumption of LCS vs sugar decreases BW, and that it does so via decreasing daily EI.”

The effects of low-calorie sweeteners on energy intake and body weight: a systematic review and meta-analyses of sustained intervention studies. Int J Obes (Lond)
Who: Adults and children with healthy weight, overweight or obesity in parallel-group and cross-over intervention studies
PMID 33168917

pooled analysis · 2024

“Findings from the present systematic review and meta-analysis showed that replacing an existing SSB-consumption with ASBs or water reduced BMI about 0.3 units during 6–18 months interventions.”

Substitution of sugar-sweetened beverages with non-caloric alternatives and weight change: A systematic review of randomized trials and meta-analysis. Obes Rev
Who: Children, adolescents and adults with an existing intake of sugar-sweetened beverages, randomized to replace them with artificially sweetened beverages or water or to continue SSBs (USA, Mexico, Netherlands)
PMID 37880814

Partly agree 3

pooled analysis · 2019 · landmark

“Subgroup analysis by body weight status suggested that NSS use by overweight or obese individuals (that is, those not trying to lose weight, mean body weight 86.87 kg) resulted in reduced body weight of 1.99 kg (95% confidence interval −2.84 to −1.14; three studies, n=146, duration of studies, four weeks to six months) but no change in individuals of normal weight (0.03 kg, −0.03 to 0.09; two, n=110; fig 3 ).”

Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies. BMJ
Who: Generally healthy adults and children, including those with overweight or obesity; 56 studies (RCTs, non-randomised trials and observational studies); diseased and pregnant populations excluded
PMID 30602577

controlled trial · 2012

“All groups lost weight at 3 and 6 mo ( Table 2 ; all P < 0.01); neither the DB group nor the Water group differed from the AC group at either time point.”

Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial. Am J Clin Nutr
Who: 318 overweight and obese adults aged 18-65 y (BMI 25-49.9, 84% female) consuming >=280 kcal/d of caloric beverages
PMID 22301929

controlled trial · 2020

“Although body weight and fat mass also did not differ among groups, baseline trunk fat was a significant effect modifier for these outcomes.”

Effects of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Beverages on Cardiometabolic Risk Factors, Body Composition, and Sweet Taste Preference: A Randomized Controlled Trial. J Am Heart Assoc
Who: 203 adults aged 18-40 y (BMI 18.5-40) who habitually consumed at least 1 serving/d of sugar-sweetened beverages
PMID 32696704

Disagree 1

other primary study · 2022

“In contrast, replacing SSB with LNCB was positively associated with increased weight (+0.04 kg/year, SE 0.01) and waist circumference (+0.08 cm/year, SE 0.01).”

Dose-Response and Substitution Analyzes of Sweet Beverage Consumption and Body Weight in Dutch Adults: The Lifelines Cohort Study. Front Nutr
Who: 78,286 Dutch adults from the Lifelines Cohort Study, mean age 45.9 years, 60% women
PMID 35832052

Point 2 of 2 Conflicting

Randomized trials show no clear benefit or harm of low-calorie sweeteners for weight overall

Six of ten studies found a small benefit from sweeteners in place of sugar. That goes against the idea that trials show nothing either way. One pooled analysis found 0.80 kg less body weight. Another found 1.06 kg less, with no sign of harm. Three studies agree that trials do not show a benefit you can count on, including a review in the BMJ. Compared with water or nothing, one review found sweeteners had no effect on weight.

Computed from 10 studies that test this point, each judged by two readers, in full. Sources land on both sides. 6 more studies are waiting for a full read and do not count yet.

Agree 3

pooled analysis · 2017 · landmark

“Evidence from RCTs does not clearly support the intended benefits of nonnutritive sweeteners for weight management, and observational data suggest that routine intake of nonnutritive sweeteners may be associated with increased BMI and cardiometabolic risk.”

Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. CMAJ
Who: Adults and adolescents; RCT participants were obese, overweight or hypertensive
PMID 28716847

pooled analysis · 2019 · landmark

“Body weight In randomised controlled trials, we saw no significant differences in change in body weight between adults receiving NSSs compared with those receiving different sugars or placebo (mean difference 1.29 kg, 95% confidence interval −2.80 to 0.21; five studies, n=229, very low certainty of evidence; fig 3 ).”

Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies. BMJ
Who: Generally healthy adults and children (including those with overweight or obesity); diseased populations and pregnant women excluded
PMID 30602577

controlled trial · 2012

“All interventions groups showed statistically significant weight losses by 6 mo, but there were no differences between groups.”

Replacing caloric beverages with water or diet beverages for weight loss in adults: main results of the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial. Am J Clin Nutr
Who: 318 overweight and obese adults aged 18-65 (mean BMI 36.3, 84% female, 54% black) consuming >=280 kcal/d of caloric beverages
PMID 22301929

Partly agree 1

systematic review · 2021

“Overall, there was no effect of LCS vs water/nothing on BW or BMI.”

The effects of low-calorie sweeteners on energy intake and body weight: a systematic review and meta-analyses of sustained intervention studies. Int J Obes (Lond)
Who: 60 articles reporting 88 parallel-groups and cross-over intervention studies >=1 week in children and adults with healthy weight, overweight or obesity (some with diabetes)
PMID 33168917

Disagree 6

pooled analysis · 2016 · landmark

“In all cases, the use of LES led to a relative reduction in EI, and greater loss (or reduced gain) of BW.”

Does low-energy sweetener consumption affect energy intake and body weight? A systematic review, including meta-analyses, of the evidence from human and animal studies. Int J Obes (Lond)
Who: systematic review of animal studies, human prospective cohorts and human short-term and sustained intervention studies; BW meta-analysis of sustained interventions in adults and one in children
PMID 26365102

systematic review · 2022 · landmark

“This substitution was associated with reduced body weight (MD, −1.06 kg; 95% CI, −1.71 to –0.41 kg) and lower BMI (MD, −0.32; 95% CI, −0.58 to –0.07), percentage of body fat (MD, −0.60%; 95% CI, −1.03% to –0.18%), and IHCL (standardized MD [SMD], −0.42; 95% CI, −0.70 to –0.14).”

Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk: A Systematic Review and Meta-analysis. JAMA Netw Open
Who: Adults with overweight or obesity at risk for or with diabetes (mean age 33.1 years, 77.4% women) in RCTs of LNCSBs, SSBs and/or water
PMID 35285920

pooled analysis · 2014

“In the meta-analysis of all subjects, LCS reduced body weight by 0.80 kg (95% CI: −1.17, −0.43; fixed-effect WGMD = −0.61) compared with the comparator arm.”

Low-calorie sweeteners and body weight and composition: a meta-analysis of randomized controlled trials and prospective cohort studies. Am J Clin Nutr
Who: 15 RCTs in generally healthy children and adults (mean age 4-65 y) plus 9 prospective cohorts
PMID 24944060

Show 3 more Show fewer

controlled trial · 2014

“In this 12-week weight loss study, consuming water and NNS beverages were not equivalent for weight loss, with the NNS group losing significantly more weight than the water group.”

The effects of water and non-nutritive sweetened beverages on weight loss during a 12-week weight loss treatment program. Obesity (Silver Spring)
Who: Men and women aged 21-65 with BMI 27-40 who already drank at least 3 NNS beverages per week, in a behavioral weight loss program at University of Colorado and Temple University (about 80% female)
PMID 24862170

controlled trial · 2016

“In conclusion, among participants enrolled in a comprehensive weight loss program, regular users of NNS beverages who were asked to consume NNS beverages lost significantly more weight, and maintained significantly greater weight losses, over 1 year than subjects asked to stop NNS beverage consumption and consume water alone.”

The effects of water and non-nutritive sweetened beverages on weight loss and weight maintenance: A randomized clinical trial. Obesity (Silver Spring)
Who: Adults aged 21-65 with BMI 27-40, weight stable, regular NNS beverage users, without diabetes or CVD, in a behavioral weight loss program at two US sites
PMID 26708700

pooled analysis · 2020

“Participants consuming NNS showed significant weight/BMI differences favouring NNS compared with nonusers.”

Effects of nonnutritive sweeteners on body weight and BMI in diverse clinical contexts: Systematic review and meta-analysis. Obes Rev
Who: Children, adolescents and adults with healthy weight, overweight or obesity in RCTs
PMID 32216045

What else was said but not tested?

Habitual sweetener exposure early in life changes later appetite and glucose control in rodents

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