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Added sugar

In trials, adults who ate less sugar lost about 0.8 kg and those who ate more gained about as much, an effect that disappeared when calories were matched. More sugar raised triglycerides, cholesterol and blood pressure in trials and liver fat in one. Cohorts link sugary drinks to type 2 diabetes and heart disease. Sugar did not lift mood.

Add to Bio HackChecked 2026-11-13
Status
A food, not a regulated health product. The FDA Daily Value for added sugars is 50 g a day on a 2,000-calorie diet, and the FDA states the Dietary Guidelines for Americans advise keeping calories from added sugars under 10% a day [1]. The World Health Organization's limit for free sugars is under 10% of daily energy, with further benefit suggested below 5% [2].
Also called
sugar, table sugar, sucrose, free sugars, sugar-sweetened beverages, SSBs, soda, soft drinks, sugary drinks, high-fructose corn syrup, syrups, sweets
Studied for
energy, sugar rush, mood, focus, weight gain, type 2 diabetes, heart disease, tooth decay, fatty liver, hyperactivity in children, sugar addiction

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help1

Reported risks5

What it was studied for, and what was found

Shown to help1

Strong

Body weight, eating less or more sugar

Shown to lower body weight about 0.8 kg when adults ate less sugar, and to raise it as much when they ate more. Swapping sugar for other carbohydrates changed nothing.

Compared with groups eating more sugar, or less, in trials of freely chosen diets [3]; other carbohydrates with the same calories [3]; control groups in trials that cut or added sugar-sweetened drinks [4]

The numbers and sources
Effect
In adults on freely chosen diets, eating less sugar lowered body weight by 0.80 kg (95% CI 0.39 to 1.21) and eating more raised it by 0.75 kg (95% CI 0.30 to 1.19). Exchanging sugars for other carbohydrates with the same calories did not change weight (0.04 kg, 95% CI -0.04 to 0.13). Trials advising children to cut sugar had low compliance and found no overall weight change [3]. Adding sugar-sweetened drinks raised adult body weight by 0.85 kg (95% CI 0.50 to 1.20). Cutting them in children reduced BMI gain by 0.17 units (random effects 95% CI -0.39 to 0.05, fixed effects significant) [4]. In cohorts, the highest intake of sugar-sweetened drinks was linked to 55% higher odds of overweight after a year [3].
Population
30 trials and 38 cohort studies in adults and children [3]. 5 trials in 2,772 children and 5 trials in 292 adults, plus 22 cohorts [4].
Sources
[3], [4]
Caveats
The weight change came from calories, since equal-calorie swaps changed nothing [3]. Trials were short, and the children's result depends on the statistical model used [4].

Not shown to help2

Moderate

Mood and energy, the sugar rush

Not shown to lift mood at any point after eating it, in a meta-analysis of 31 studies. Fatigue was higher and alertness lower in the first hour.

Compared with placebo [5]

The numbers and sources
Effect
Across 176 effect sizes, carbohydrate had no positive effect on any aspect of mood at any time after eating. In the first hour, it was linked to more fatigue and less alertness than placebo [5].
Population
1,259 participants in 31 studies [5].
Sources
[5]
Caveats
The review covered carbohydrate in general, mostly sugars, taken in single doses. It does not test daily eating patterns.
ModerateStudied in children

Behavior and thinking in children

Not shown to change behavior or thinking in children against an artificial sweetener placebo, in a meta-analysis of 23 blinded studies.

Compared with an artificial sweetener placebo, with children, parents and staff blinded [6]

The numbers and sources
Effect
Across 14 measures of behavior and thinking, effect sizes ranged from -0.14 for direct observation to +0.30 for academic tests, and every 95% confidence interval included zero [6].
Population
Children in 23 within-subject studies from 16 reports [6].
Sources
[6]
Caveats
The authors note a small effect, or effects in some children, cannot be ruled out [6]. The review dates from 1995.

Amounts studied

Trials changed sugar intake in adults eating freely for at least 2 weeks [3], or added sugar-sweetened drinks in adults and replaced or discouraged them in children [4]. Cohorts compared one serving a day of sugar-sweetened drinks [7], quantiles of intake [8][9], or the share of daily calories from added sugar, under 10%, 10% to 24.9% and 25% or more [10]. Lipid and blood pressure trials compared higher with lower free sugar intakes for at least 2 weeks [11]. The liver fat trial gave 1 L a day of regular cola for 6 months [12]. The tooth decay review compared free sugar intakes below and above 10% and 5% of energy [13].

Risks

Reported risks5

LimitedHow often is not known

Type 2 diabetes

Linked to type 2 diabetes in cohorts, 13% to 18% higher per daily serving of sugar-sweetened drinks, and 26% higher at the highest intakes.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Each daily serving of sugar-sweetened drinks was linked to 18% more type 2 diabetes (95% CI 9% to 28%), and 13% (95% CI 6% to 21%) after adjusting for body fat [7]. People drinking 1 to 2 servings a day had 26% higher risk than those drinking under 1 a month (RR 1.26, 95% CI 1.12 to 1.41) [8]. A 2023 meta-analysis found RR 1.27 (95% CI 1.17 to 1.38) for the highest intakes [9].
Population
17 cohorts with 38,253 cases [7]. 310,819 participants with 15,043 cases [8]. 72 articles of prospective studies [9].
Sources
[7], [8], [9]
Caveats
Observational. Heterogeneity was high (I² 89%) [7], and people who drink more sugary drinks differ in other ways. Artificially sweetened drinks were also linked to diabetes, which points to confounding or reverse causation in these studies [7][9].
LimitedHow often is not known

Heart disease, stroke and death

Linked to heart disease and death in cohorts. US adults getting 25% or more of calories from added sugar had 2.75 times the heart death risk.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Against under 10% of calories from added sugar, 10% to 24.9% was linked to higher cardiovascular death (HR 1.30, 95% CI 1.09 to 1.55) and 25% or more to HR 2.75 (95% CI 1.40 to 5.42) [10]. An umbrella review found each 250 mL a day more of sugar-sweetened drinks linked to 17% more coronary heart disease and 4% more death from any cause, on low quality evidence [14]. A 2023 meta-analysis linked these drinks to hypertension, stroke and death from any cause, with relative risks from 1.08 to 1.54 [9].
Population
11,733 US adults followed a median 14.6 years, 831 cardiovascular deaths [10]. 73 meta-analyses [14]. 72 articles [9].
Sources
[10], [14], [9]
Caveats
Observational, open to confounding and reverse causation. The umbrella review rated these links low quality [14].
ModerateHow often is not known

Blood fats and blood pressure

Shown to raise triglycerides, total and LDL cholesterol and blood pressure in trials of higher against lower sugar intake, independent of body weight.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Higher sugar intake raised triglycerides by 0.11 mmol/L (95% CI 0.07 to 0.15), total cholesterol by 0.16 mmol/L (95% CI 0.10 to 0.24), LDL cholesterol by 0.12 mmol/L (95% CI 0.05 to 0.19) and HDL cholesterol by 0.02 mmol/L (95% CI 0.00 to 0.03). In trials of 8 weeks or longer, systolic pressure rose 6.9 mmHg (95% CI 3.4 to 10.3) and diastolic 5.6 mmHg [11]. A liter of regular cola a day for 6 months raised triglycerides 32% and total cholesterol 11% more than milk, diet cola or water [12].
Population
37 trials reporting lipids and 12 reporting blood pressure, each at least 2 weeks [11]. 47 overweight adults [12].
Sources
[11], [12]
Caveats
Heterogeneity was moderate to high (I² 36% to 75%) [11]. The cola trial was small.
LimitedHow often is not known

Liver fat

One trial found a liter of regular cola daily for 6 months raised liver fat more than milk, diet cola or water. Cross-sectional studies link sugary drinks to fatty liver.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Relative changes in liver fat, muscle fat (117% to 221%) and visceral fat (24% to 31%) were larger with regular cola than with the other three drinks, while total fat mass did not differ [12]. In 4 cross-sectional studies, the highest intake of sugar-sweetened drinks was linked to 40% higher odds of non-alcoholic fatty liver disease (OR 1.40, 95% CI 1.07 to 1.82) [15]. An umbrella review rated the link between added sugars and fat stored in organs as moderate quality [14].
Population
47 overweight adults [12]. 6,326 participants with 1,361 cases [15]. 73 meta-analyses [14].
Sources
[12], [15], [14]
Caveats
One small trial. Cross-sectional studies cannot show which came first.
ModerateHow often is not known

Tooth decay

Linked to more tooth decay in 42 of 50 studies in children and all 5 in adults, with moderate quality evidence of less decay below 10% of energy.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
A systematic review for the World Health Organization found at least one positive association between sugars and caries in 42 of 50 studies in children and 5 of 5 in adults. Evidence that caries is lower when free sugars are under 10% of energy was rated moderate quality, and under 5% very low quality [13].
Population
55 studies: 3 intervention, 8 cohort, 20 population and 24 cross-sectional [13].
Sources
[13]
Caveats
Most studies were observational, and variation between them prevented pooling [13].

Possible, not studied in people1

Untested

Sugar addiction

Not studied in people as an addiction. Rats given intermittent sugar access showed bingeing, withdrawal-like and craving behaviors, and a review found little support in humans.

No study in people. This rests on animal studies.

The numbers and sources
Effect
In rats with intermittent access to sugar, bingeing, withdrawal, craving and cross-sensitization were each shown, with brain changes also seen with addictive drugs [16]. A later review found little evidence for sugar addiction in humans and concluded that the animal behaviors arise from intermittent access to sweet or palatable foods rather than from sugar's effects in the brain [17].
Population
Rats [16]. A review of animal and human literature [17].
Sources
[16], [17]
Caveats
Animal findings under intermittent access schedules do not show addiction in people [17].

Claims tested and not found

  1. That sugar gives a mood lift or a burst of energy. A meta-analysis of 31 studies found no positive effect on mood at any time point, and more fatigue and less alertness in the first hour [5].
  2. That sugar makes children hyperactive. Blinded studies against an artificial sweetener found no effect on behavior or thinking [6].
  3. That sugar causes weight gain separately from its calories. Swapping sugars for other carbohydrates with the same calories did not change body weight in trials [3].

Sources

  1. U.S. Food and Drug Administration. Added Sugars on the Nutrition Facts Label. 2026. https://www.fda.gov/food/nutrition-facts-label/added-sugars-nutrition-facts-label
  2. World Health Organization. Healthy diet. Fact sheet. 2026. https://www.who.int/news-room/fact-sheets/detail/healthy-diet
  3. Te Morenga L, Mallard S, Mann J. Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies. BMJ. 2013. https://doi.org/10.1136/bmj.e7492
  4. Malik VS, Pan A, Willett WC, Hu FB. Sugar-sweetened beverages and weight gain in children and adults: a systematic review and meta-analysis. The American Journal of Clinical Nutrition. 2013. https://doi.org/10.3945/ajcn.113.058362
  5. Mantantzis K, Schlaghecken F, Sünram-Lea SI, Maylor EA. Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood. Neuroscience and Biobehavioral Reviews. 2019. https://doi.org/10.1016/j.neubiorev.2019.03.016
  6. Wolraich ML, Wilson DB, White JW. The effect of sugar on behavior or cognition in children. A meta-analysis. JAMA. 1995. https://doi.org/10.1001/jama.1995.03530200053037
  7. Imamura F, O'Connor L, Ye Z, et al. Consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review, meta-analysis, and estimation of population attributable fraction. BMJ. 2015. https://doi.org/10.1136/bmj.h3576
  8. Malik VS, Popkin BM, Bray GA, et al. Sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis. Diabetes Care. 2010. https://doi.org/10.2337/dc10-1079
  9. Li B, Yan N, Jiang H, et al. Consumption of sugar sweetened beverages, artificially sweetened beverages and fruit juices and risk of type 2 diabetes, hypertension, cardiovascular disease, and mortality: A meta-analysis. Frontiers in Nutrition. 2023. https://doi.org/10.3389/fnut.2023.1019534
  10. Yang Q, Zhang Z, Gregg EW, et al. Added sugar intake and cardiovascular diseases mortality among US adults. JAMA Internal Medicine. 2014. https://doi.org/10.1001/jamainternmed.2013.13563
  11. Te Morenga LA, Howatson AJ, Jones RM, Mann J. Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. The American Journal of Clinical Nutrition. 2014. https://doi.org/10.3945/ajcn.113.081521
  12. Maersk M, Belza A, Stødkilde-Jørgensen H, et al. Sucrose-sweetened beverages increase fat storage in the liver, muscle, and visceral fat depot: a 6-mo randomized intervention study. The American Journal of Clinical Nutrition. 2012. https://doi.org/10.3945/ajcn.111.022533
  13. Moynihan PJ, Kelly SA. Effect on caries of restricting sugars intake: systematic review to inform WHO guidelines. Journal of Dental Research. 2014. https://doi.org/10.1177/0022034513508954
  14. Huang Y, Chen Z, Chen B, et al. Dietary sugar consumption and health: umbrella review. BMJ. 2023. https://doi.org/10.1136/bmj-2022-071609
  15. Asgari-Taee F, Zerafati-Shoae N, Dehghani M, et al. Association of sugar sweetened beverages consumption with non-alcoholic fatty liver disease: a systematic review and meta-analysis. European Journal of Nutrition. 2019. https://doi.org/10.1007/s00394-018-1711-4
  16. Avena NM, Rada P, Hoebel BG. Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake. Neuroscience and Biobehavioral Reviews. 2008. https://doi.org/10.1016/j.neubiorev.2007.04.019
  17. Westwater ML, Fletcher PC, Ziauddeen H. Sugar addiction: the state of the science. European Journal of Nutrition. 2016. https://doi.org/10.1007/s00394-016-1229-6

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