Can sugar cause anxiety?

Nobody has shown that it does. We found no randomized trial that cut sugar and measured anxiety, and none registered. The closest experiments, 31 placebo-controlled studies in 1259 people given a single dose of carbohydrate or sugar, found no lift in any aspect of mood. In observational data, a 2024 meta-analysis of 9 studies in 88,046 people found no significant link between total sugar and anxiety (OR 1.11, 95% CI 0.93 to 1.28). Some large cohorts do tie heavy sugar and sugary drinks to more anxiety. Those studies cannot tell whether the sugar came first.

Unsettled. The answer stays open because the two kinds of evidence never meet. The trials gave one dose and watched mood for an hour, with anxiety as one item on a wider scale. The studies of everyday eating cover years, but most are cross-sectional snapshots, and anxious people may reach for sweet food as easily as sweet food may feed anxiety.

What the trials found

A dose of sugar and mood in the next hour

A meta-analysis of 31 placebo-controlled studies in 1259 people pooled 176 effect sizes and found no positive effect of carbohydrate on any aspect of mood at any time point. Within the first hour after eating it, people reported more fatigue and less alertness than on placebo. The abstract does not say how large that difference was. These were single-dose studies, so they say nothing about years of eating.

Myth. Sugar is not a quick mood lift. Across 31 controlled studies it lifted no aspect of mood at any point, and in the first hour it left people more tired and less alert than placebo.

Cutting carbohydrate does not ease anxiety

A meta-analysis of 8 randomized trials in 590 people found that low-carbohydrate diets did not reduce anxiety (SMD 0.19, 95% CI -0.10 to 0.47). The diets cut all carbohydrate, not sugar alone, and most trials were weight-loss studies that could not be blinded. In the trials where carbohydrate fell below 26% of energy, anxiety scores went up (SMD 0.31, 95% CI 0.10 to 0.52). That is a subgroup result.

A sugar drink before surgery in children

A meta-analysis of 14 randomized trials in 1428 patients aged 18 or younger found that a carbohydrate drink before surgery, in place of fasting, reduced anxiety at the start of anesthesia. The abstract gives no size for the effect. This is a child who has gone without food before an operation, and it tells us nothing about sugar in an ordinary day.

What observational studies show

The pooled 2024 analysis is the widest view. In its 9 anxiety studies, 8 of them cross-sectional, the link with total sugar did not reach significance and the studies disagreed sharply with each other (I2 = 99.7%). In the same review the link with depression was significant (OR 1.21, 95% CI 1.14 to 1.27), and the authors judged the anxiety evidence insufficient.

Narrower questions give firmer associations. A 2026 meta-analysis of studies in adolescents linked higher sugary drink intake with 34% higher odds of an anxiety disorder (OR 1.34, 95% CI 1.14 to 1.59). Those drinks include energy drinks and caffeinated sodas, so caffeine may explain part of it, and most of the studies were cross-sectional. In 169,776 UK Biobank adults followed for about 10.5 years, high intake of total sugars went with a 20% higher hazard of anxiety (HR 1.20, 95% CI 1.13 to 1.28) and high sucrose with 28% (HR 1.28, 95% CI 1.21 to 1.37). In 84,087 adults from the same biobank, sucrose and anxiety scores followed a J-shaped curve in both sexes, in a single snapshot.

In the Whitehall II study of British civil servants, men in the top third of sugar intake from sweet food and drinks had 23% higher odds of a new common mental disorder after 5 years (OR 1.23, 95% CI 1.02 to 1.48). That outcome lumps anxiety and depression together, and the finding was in men only. Two systematic reviews that did not pool their studies, one of 26 studies and one of 11, both describe a possible positive link between sugar and anxiety and call for better long-term studies.

Who should be careful

Not for everyone. Cutting carbohydrate very hard is not a safe anxiety fix. In randomized trials of diets with under 26% of energy from carbohydrate, anxiety scores rose (SMD 0.31, 95% CI 0.10 to 0.52), in a subgroup of a meta-analysis of 8 trials.

In children before surgery, a standard sugar drink carried a risk of higher blood glucose after the operation, while a compound carbohydrate drink had a better metabolic safety record. The review does not say how large the risk was, and the choice of drink belongs to the surgical team. We found no study of sugar and anxiety in pregnancy, in people with diabetes or alongside medicines. We also looked for an agency page on the overlap between low blood sugar and anxiety symptoms and found none we could use.

What expert bodies say

WHO recommends that adults and children keep free sugars below 10% of daily energy, as a strong recommendation, and suggests going below 5%. The limit covers free sugars, and does not apply to the sugar inside whole fruit, vegetables or milk. WHO bases these limits on body weight and tooth decay. Neither anxiety nor mental health is part of that evidence. We found no position from NIH, NICE or WHO on sugar and anxiety.

How we searched

What would change this answer

• A randomized trial that cuts sugar or sugary drinks for several weeks and makes anxiety its main outcome. We found none finished and none registered.
• Long cohort studies that measure sugar and anxiety more than once, so the order of the two can be seen. Most of what exists is a single snapshot.
• Studies of sugary drinks that separate the sugar from the caffeine.

What sugar does on the plate, and the limits that apply to it, are on the sugar page.

Sources

1. ev-sgax-01 · Meta-analysis or systematic review · systematic review and meta-analysis of placebo-controlled experimental studies · n = 1259
   Analysis of 176 effect sizes (31 studies, 1259 participants) revealed no positive effect of CHOs on any aspect of mood at any time-point following their consumption.
   
   Who: adults given an acute carbohydrate dose (mostly sugar drinks) or placebo in experimental studies
   Effect: no positive effect of carbohydrate on any mood dimension across 176 effect sizes
   Certainty: Acute single-dose studies; mood scales include tension and anxiety items; long-term intake not tested.
   Neurosci Biobehav Rev, 2019 · checked 2026-10-07 · we read the abstract
2. ev-sgax-02 · Meta-analysis or systematic review · systematic review and meta-analysis of placebo-controlled experimental studies · n = 1259
   However, CHO administration was associated with higher levels of fatigue and less alertness compared with placebo within the first hour post-ingestion.
   
   Who: adults in placebo-controlled acute carbohydrate studies
   Effect: higher fatigue and lower alertness vs placebo within 60 minutes
   Certainty: Short-term effect; size of the difference not given in the abstract.
   Neurosci Biobehav Rev, 2019 · checked 2026-10-07 · we read the abstract
3. ev-sgax-03 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 590
   This study did not show any significant association between a low carbohydrate diet and the of anxiety (SMD = 0.19, 95 % CI -0.10, 0.47; P = 0.20) and also depression (SMD = 0.06, 95 % CI -0.11, 0.24; P = 0.49).
   
   Who: adults on low-carbohydrate diets vs control diets in randomized trials
   Effect: anxiety SMD 0.19 (95% CI -0.10 to 0.47; P = 0.20); depression SMD 0.06 (95% CI -0.11 to 0.24)
   Certainty: Diets cut total carbohydrate, not sugar alone; blinding not possible; trials were mostly weight-loss studies.
   J Affect Disord, 2023 · checked 2026-10-07 · we read the abstract
4. ev-sgax-04 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials, subgroup analysis · n = 590
   This study showed that this diet increases anxiety in studies with <26 % carbohydrate intake (SMD = 0.31; 95%CI 0.10, 0.52; P ≤ 0.001; I2 = 0.00, P = 0.52)
   
   Who: adults in RCTs of very low carbohydrate diets (<26% of energy)
   Effect: anxiety SMD 0.31 (95% CI 0.10 to 0.52) at <26% carbohydrate; I2 = 0
   Certainty: Subgroup finding; caution against very strict carbohydrate cutting as an anxiety fix.
   J Affect Disord, 2023 · checked 2026-10-07 · we read the abstract
5. ev-sgax-05 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 1428
   It effectively improves cooperation during anesthesia induction (reducing anxiety and enhancing sedation) and stabilizes metabolic status (the compound carbohydrate solution reduces postoperative insulin levels and insulin resistance).
   
   Who: patients aged 18 or younger before surgery, carbohydrate drink vs fasting or placebo
   Effect: lower anxiety and better cooperation at induction; fewer cases of postoperative nausea and vomiting
   Certainty: Surgical setting with fasting stress; effect size not given in the abstract; not about everyday sugar intake.
   J Pediatr Surg, 2026 · checked 2026-10-07 · we read the abstract
6. ev-sgax-06 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 1428
   Notably, while a standard carbohydrate solution carries a risk of elevating postoperative blood glucose, the compound carbohydrate solution demonstrates a more favorable metabolic safety profile.
   
   Who: patients aged 18 or younger before surgery
   Effect: standard carbohydrate solution may raise postoperative blood glucose; compound solution safer
   Certainty: Safety signal for glucose, size not given in the abstract.
   J Pediatr Surg, 2026 · checked 2026-10-07 · we read the abstract
7. ev-sgax-07 · Observational data · systematic review and meta-analysis of observational studies (8 cross-sectional, 1 cohort for anxiety) · n = 88,046
   The overall odds ratio (OR) for the association between sugar intake and anxiety risk was 1.11 (95% CI: 0.93, 1.28; Table 2; Figure 3).
   
   Who: general population in cross-sectional and cohort studies
   Effect: anxiety OR 1.11 (95% CI 0.93 to 1.28; I2 = 99.7%); depression OR 1.21 (95% CI 1.14 to 1.27) in the wider 40-study set
   Certainty: Very high heterogeneity; mostly cross-sectional; OR is odds, not risk.
   Front Nutr, 2024 · checked 2026-10-07 · we read the fulltext
8. ev-sgax-08 · Observational data · systematic review and meta-analysis of observational studies · n = 1,212,107
   Results showed that sugar intake increased the risk of depression by 21% (OR = 1.21, 95% CI: 1.14, 1.27), while the overall association between sugar intake and anxiety risk was not statistically significant (OR = 1.11, 95% CI: 0.93, 1.28).
   
   Who: general population, 40 observational studies
   Effect: depression OR 1.21 (95% CI 1.14 to 1.27); anxiety OR 1.11 (95% CI 0.93 to 1.28)
   Certainty: Association only; reverse causation (low mood leading to sweet eating) not excluded.
   Front Nutr, 2024 · checked 2026-10-07 · we read the abstract
9. ev-sgax-09 · Observational data · systematic review and meta-analysis of observational studies · n = —
   The meta-analysis random effects model which is limited to studies reporting anxiety disorder as binary outcome revealed that higher sugar-sweetened beverage consumption was associated with increased odds of anxiety disorders (OR: 1.34, 95% CI: 1.14-1.59).
   
   Who: adolescents in 9 studies (7 cross-sectional, 2 longitudinal)
   Effect: anxiety disorder OR 1.34 (95% CI 1.14 to 1.59) for higher sugar-sweetened beverage intake
   Certainty: Sugary drinks include energy drinks and caffeinated sodas, so caffeine may confound; mostly cross-sectional.
   J Hum Nutr Diet, 2026 · checked 2026-10-07 · we read the abstract
10. ev-sgax-10 · Observational data · systematic review of observational studies, no meta-analysis · n = —
    However, an overall positive association was observed between high intake of sugar and increased risk of anxiety and depressive symptoms in different populations across the globe.
    
    Who: children, adolescents and adults in 14 cross-sectional, 10 cohort and 2 case-control studies
    Effect: overall positive association; no pooled estimate because of heterogeneity
    Certainty: Direction only; causal direction unknown.
    Obes Rev, 2026 · checked 2026-10-07 · we read the abstract
11. ev-sgax-11 · Observational data · systematic review · n = —
    The findings suggest a possible positive relationship of added sugar consumption with anxiety disorders, with age as a potential moderator in such association.
    
    Who: 10 cross-sectional studies and 1 RCT on sugar intake and anxiety disorders
    Effect: possible positive association for added sugar; inconclusive for sugar-sweetened beverages and foods
    Certainty: Mostly cross-sectional; authors call for longitudinal studies.
    Nutr Bull, 2024 · checked 2026-10-07 · we read the abstract
12. ev-sgax-12 · Observational data · prospective cohort study · n = 169,776
    Compared to low intake, high intake of total sugars, free sugar, lactose, non-milk extrinsic sugars, and sucrose was associated with an increased risk of depression (HR = 1.26, 95% CI [1.18-1.33], 1.23 [1.16-1.30], 1.15 [1.08-1.22], 1.24 [1.17-1.32], and 1.33 [1.25-1.41]), anxiety (1.20 [1.13-1.28], 1.22 [1.14-1.29], 1.16 [1.09-1.23], 1.23 [1.15-1.31], and 1.28 [1.21-1.37]), and self-harm (1.37 [1.08-1.75], 1.35 [1.06-1.72], 1.64 [1.27-2.11], 1.45 [1.14-1.84], and 1.37 [1.08-1.75]).
    
    Who: UK Biobank adults with at least one Oxford WebQ diet record, median follow-up 10.54 years
    Effect: anxiety HR 1.20 (1.13 to 1.28) total sugars, 1.22 (1.14 to 1.29) free sugar, 1.28 (1.21 to 1.37) sucrose, high vs low intake
    Certainty: Association; U and J shaped curves; residual confounding by diet quality and weight possible.
    J Nutr Health Aging, 2025 · checked 2026-10-07 · we read the abstract
13. ev-sgax-13 · Observational data · prospective analysis of repeated measures in a cohort · n = 23,245
    In prospective analyses, men in the highest tertile of sugar intake from sweet food/beverages had a 23% increased odds of incident CMD after 5 years (95% CI: 1.02, 1.48) independent of health behaviours, socio-demographic and diet-related factors, adiposity and other diseases.
    
    Who: British civil servants, 23,245 person-observations
    Effect: incident common mental disorder OR 1.23 (95% CI 1.02 to 1.48) in men, highest vs lowest tertile
    Certainty: Common mental disorder covers anxiety and depression together; finding in men only.
    Sci Rep, 2017 · checked 2026-10-07 · we read the abstract
14. ev-sgax-14 · Observational data · cross-sectional analysis with generalized additive models · n = 84,087
    Specifically, the association between sucrose consumption and GAD score followed a J-shaped pattern in both genders.
    
    Who: UK Biobank adults with GAD-7 scores and Oxford WebQ diet data
    Effect: J-shaped association of sucrose with GAD-7 score; non-linear links for total sugar in people aged 45 or younger
    Certainty: Cross-sectional; thresholds not causal.
    Nutr J, 2026 · checked 2026-10-07 · we read the abstract
15. ev-sgax-15 · Position of an expert body · WHO guideline · n = —
    In both adults and children, WHO recommends reducing the intake of free sugars to less than 10% of total energy intake2 (strong recommendation). WHO suggests a further reduction of the intake of free sugars to below 5% of total energy intake (conditional recommendation3).
    
    Who: adults and children
    Effect: free sugars <10% of energy (strong), <5% (conditional)
    Certainty: Upper limit for intake; applies to free sugars, not sugars inside whole fruit, vegetables or milk.
    WHO, 2015, Guideline: sugars intake for adults and children · checked 2026-10-07 · we read the section
16. ev-sgax-16 · Position of an expert body · WHO guideline · n = —
    These recommendations were based on the totality of evidence reviewed regarding the relationship between free sugars intake and body weight (low and moderate quality evidence) and dental caries (very low and moderate quality evidence).
    
    Who: adults and children
    Effect: evidence base: body weight and dental caries
    Certainty: No major agency sets a sugar limit on mental health grounds.
    WHO, 2015, Guideline: sugars intake for adults and children · checked 2026-10-07 · we read the section