Table 2.

Intervention trial characteristics.

Author/s	Population	Cognitive Measures	Intervention/Control	Fasting	Major Findings
Adan and Serra-Grabulosa, 2010 [51]	N = 72 young adults (36 male) aged 18–25 (M = 21.07, SD = 1.70)	RAVLT, Purdue–Pegboard, Benton Judgement of Line Orientation Test (JoLO), WCST, California Computerized Assessment Package (CalCAP), digit span of WAIS	(1)75 mg caffeine, (2)75 mg glucose, (3)75 mg caffeine + 75 mg glucose, (4)Water	8 h	Water performed worse than treatment groups (p = 0.026). Glucose performed better on Purdue pegboard assembly than placebo or caffeine (p = 0.039). No effect of treatment on reaction time, WAIS, WCST, and RAVLT.
Allen et al., 1996 [62]	N = 28 elderly adults (6 male) aged 61–87 (M = 73)	Rey–Osterrieth Complex Figure, Taylor Complex Figure, dichotic listening, TMT, verbal fluency, Boston naming test, Meier visual test, grooved pegboard, figural fluency	(1)50 g glucose, (2)23.7 mg saccharin	9 h	Glucose enhanced delayed recall and verbal and figure fluency (ps < 0.001). No effect of glucose on other measures. Poor glucose regulation associated with worse performance in dichotic listening (p < 0.005) and verbal fluency (p < 0.05).
Azari, 1993 [63]	N = 18 young male adults aged 19–25 (M = 21, SD = 1.65)	Word recall	(1)30 g glucose + 350 mg aspartame, (2)100 mg glucose, (3)450 mg aspartame	4.5 h	No effect of glucose or BGL on memory.
Benton et al., 1987 [64]	N = 60 children (30 male) aged 6 or 7 years old.	Paradigm of Shakow	(1)25 g glucose, (2)Saccharin	2–3 h	Improved reaction time after glucose (p ≤ 0.05). Glucose group reported increased quiet concentration (p < 0.001) and less likely to fidget (p < 0.04).
Benton, 1990 [65]	T1: N = 20 male students (M age = 20.3 and 20.5 per group) T2: N = 40 undergraduate students (20 male; M age = 21.2 and 20.9)	T1: choice reaction time task T2: long arithmetic	(1)25 g glucose, (2)Aspartame	4 h	T1: Glucose associated with fewer errors (p < 0.05). T2: No effect of glucose on coordination or arithmetic. Males performed better on arithmetic (p < 0.001) and coordination (p < 0.01).
Benton and Owens, 1993 [66]	T1: N = 153 undergraduate students (100 male, M age = 21.6, SD = 4.8; 53 female, M age = 21.8, SD = 5.2) T2: N = 53 female undergraduates (M = 21.5, SD = 5.0)	T1: word list, pattern recognition T2: word list, Weschler memory scale	T1: (1)50 g glucose, (2)Aspartame + acesulfame K T2: (1)Sustained glucose (50 g + two 25 g top-ups)	No	T1: No effect of glucose on recall or spatial memory. Increased BGL associated with more words remembered (p < 0.002). T2: No effect of glucose on Weschler or word list. Falling BGL in glucose group associated with improved memory; falling BGL in placebo group associated with worse memory.
Benton et al., 1994 [67]	T1: N = 70 female undergraduates (M age = 21.46) T2: N = 50 male undergraduates (M age = 21.7)	T1: RIPT T2: STROOP	(1)50 g glucose + 25 g glucose; (2)Aspartame + acesulfame K	No	Glucose associated with more errors than placebo in RIPT (p < 0.031). No effect of glucose on memory, reaction time, or STROOP.
Benton and Stevens, 2008 [68]	N = 16 children (7 male) aged 9 or 10 years	Recall of objects test, pattern recognition, paradigm of Shakow	(1)25 g glucose, (2)25 g xylitol	No	More pictures recalled after glucose consumption (p < 0.025). No effect of glucose on spatial memory.
Best et al., 2008 [69]	N = 45 adults (19 male) aged 40–63 (M = 52.1, SD = 5.9)	RAVLT, Self-Ordered Pointing Task (SOPT), digit span, WAIS matrix reasoning	(1)25 g glucose, (2)7 g saccharide + 2 drops stevia	2 h	No effect of glucose on any outcome.
Birnie et al., 2015 [70]	N = 16 adults (8 male) aged 18–45 (M = 23.7, SD = 5.0)	SART, Short Imaginal Processes Inventory (SIPI)	(1)25 g glucose, (2)Saccharin	2 h	No effect of glucose on any outcome.
Brandt et al., 2006 [71]	T1: N = 40 undergraduate students (20 male) aged 18–25 T2: N = 40 undergraduate students (14 male) aged 18–36 (M = 22)	Word list	(1)25 g glucose, (2)Aspartame	2 h	No effect of glucose on emotional memory enhancement. BGL were negatively associated with positive items remembered (p < 0.05). Better glucoregulation associated with improved memory for negative items and fewer errors (ps < 0.05).
Brandt et al., 2010 [72]	T1: N = 40 undergraduate students (5 male) aged 18–34 (M = 19.1) T2: N = 40 undergraduate students (27 male) aged 18–37 (M = 21)	Word list	T1: (1)15 g glucose, (2)Aspartame T2: (1)25 g glucose, (2)Aspartame	2 h	Greater false alarm rate after 25 g glucose condition (p < 0.05) Recognition memory was marginally improved in the aspartame group (p = 0.05).
Brandt et al., 2013 [73]	N = 60 undergraduate students (14 male; M age = 19.7)	STROOP	(1)25 g glucose, (2)Aspartame	Overnight	Shorter reaction times in congruent and incongruent conditions after glucose consumption (ps < 0.05). Greater facilitative effect of glucose in incongruent (higher cognitive load) task.
Brandt, 2015 [74]	N = 41 undergraduate students (9 male; M age = 19.47)	Process dissociation procedure	(1)25 g glucose, (2)Aspartame	Overnight	Exclusion (high effort condition) was superior in glucose condition (p < 0.05). No effect of treatment on inclusion. Aspartame scored higher in familiarity (p < 0.01) (low effort condition). No effect of treatment on recollection.
Brody and Wolitzky, 1983 [75]	N = 59 undergraduate students (28 male) aged 16–24 (M = 18.7)	Serial sevens	(1)100 g sucrose, (2)52 mg saccharin, (3)Water	8 h	No effect of treatment.
Brown and Riby, 2013 [76]	N = 35 young adults (14 male) aged 18–35 (M = 22.17, SD = 5.97)	Item recognition task, STROOP	(1)25 g glucose, (2)37.5 mg saccharin	2 h	Glucose facilitation effect in more difficult task conditions, but glucose impaired performance on new items (low cognitive load) (p = 0.02). No effect of glucose on attention.
Craft et al., 1994 [77]	N = 59 (27 younger adults aged 19–28, M = 20.8; 32 older adults aged 58–77, M = 68.5)	Paced Serial Addition Test, paragraph recall, modified CVLT, pattern recall and recognition, serial reaction time, word generation	(1)50 g glucose, (2)23.7 mg saccharin (a)Male vs. female, (b)Young vs. old, (c)Good vs. poor glucose control	Overnight	Glucose improved declarative memory in older males with good glycaemic recovery (p < 0.01). Glucose improved recall in younger men with poor glycaemic recovery (p < 0.01). Younger men with good glycaemic recovery saw memory deterioration after glucose consumption (p < 0.001). No effect of glucose on procedural memory, working memory, or verbal fluency.
Donohoe and Benton, 1999a [78]	T1: N = 67 female undergraduate students (M age = 21.8, SD = 5.1) T2: N = 69 female undergraduates (M age = 20.2, SD = 2.1)	T1: water jar test, Finding Embedded Figures Test, Baddeley Logical Reasoning Task T2: Controlled Oral Word Association Test, WAIS—Block design subtest, Porteus maze—adults/14 year olds	(1)50 g glucose, (2)Aspartame and saccharin	No	T1: No effect of glucose on outcomes. T2: Improved verbal fluency after glucose consumption (p < 0.001). Faster time to solve Porteus maze for 14 year olds after glucose (p < 0.002). No effect of glucose on block design.
Donohoe and Benton, 1999b [79]	N = 188 female undergraduate students (M age 21, SD = 4)	T1: RIPT, word list	(1)50 g glucose, (2)Aspartame and saccharin	No	Faster recall for glucose compared to control (p < 0.001). No effect of glucose on recall. More errors in the placebo group at 2, 4 (ps < 0.01), and 6 min (p < 0.05) (but not 8 or 10 min) of RIPT vigilance task.
Flint and Turek, 2003 [80]	N = 67 Undergraduate students (15 male) aged 18–50 (M = 19.49, SD = 4.35)	Test of Variable of Attention (TOVA)	(1)10 mg/kg glucose, (2)100 mg/kg glucose, (3)500 mg/kg glucose, (4)23.7 mg saccharin	8 h	100 mg/kg showed impaired impulsivity (greater postcommission response time variability) (p < 0.01). No effect of treatment on any other measure.
Ford et al., 2002 [81]	N = 20 undergraduate students aged 20–23	Tailored version of CDR Assessment Battery	(1)25 g glucose, (2)28 mg saccharin	Overnight	No effect of glucose on memory.
Foster et al, 1998 [52]	N = 30 female young adults aged 18–22 years (M = 19.5)	Modified CVLT, ROCF, digit span	(1)25 g glucose, (2)37.5 mg saccharin, (3)Water	9 h	Improved delayed recall after glucose consumption (p < 0.05). No effect of treatment on any other outcome.
Giles et al., 2018 [82]	N = 105 young adults (74 female; M age = 22.5, SD = 6.6)	Immediate and delayed recall, STROOP, N-back task, continuous performance task	(1)Sprite, (2)Sprite zero	12 h	Improved performance on sustained attention after sugar intake (p < 0.05). No effect of treatment on selective attention, verbal memory, or working memory.
Ginieis et al., 2018 [83]	N = 49 young adults (26 fasted (15 female, M age = 22.6, SD = 4.2) or 23 nonfasted (13 female, M age = 24.3, SD = 4.9))	Simple response time task, arithmetic task, STROOP	(1)26 g glucose, (2)14.5 g sucrose, (3)13 g fructose, (4)0.025 g sucralose, (5)Fasted vs. nonfasted	10 h	Slower reaction time after glucose consumption in the fasting group for simple response task and arithmetic task (p < 0.05). STROOP response time was impaired in the glucose and sucrose conditions, independent of fasting (p < 0.001).
Gonder-Frederick et al., 1987 [84]	N = 11 elderly adults aged 58–76 (M = 67.4, SD = 5.7)	WAIS memory subscales	(1)50 g glucose, (2)23.7 mg saccharin	9 h	Glucose group had improved performance on narrative memory (p = 0.024) and total Weschler scale (p = 0.009) (one-tailed). BGL at 30 and 60 min after beverage consumption was negatively associated with narrative memory, visual memory, and total Weschler scale (ps < 0.05).
Hope et al., 2013 [85]	T1: N = 12 young adults (6 male; M age = 25.1, SD = 2.1). T2: N = 24 young adults (3 male; M age = 20.1, SD = 0.7)	(1) Flanker task, simple version (2) Flanker task, demanding version	(1)25 g glucose, (2)2 mg saccharin	No	T1: Slower reaction time after glucose consumption (p = 0.03) only when glucose administered in session 1 and placebo in session 2. T2: Slower reaction time after glucose consumption (p = 0.045). No effect of glucose on error rates.
Jones et al., 2012 [32]	N = 18 young adults (5 male) aged 18–37 (M age = 19)	Tailored version of CDR Assessment Battery	(1)40 g glucose, (2)40 g protein + 2 g aspartame, (3)16 g fat + 2 g aspartame, (4)2 g aspartame	12 h	Enhancements in attention (p < 0.01) and speed (p < 0.05) 15 min after glucose ingestion. Impairments in working memory (p < 0.05) 60 min after glucose ingestion. Speed enhanced 15 min after fat consumption (p < 0.05). Working memory enhanced 15 min following protein ingestion (p < 0.05). Episodic memory and memory quality enhanced 60 min following protein ingestion (p < 0.01).
Kaplan et al., 2000 [31]	N = 20 older adults (10 male) aged 60–82	Tailored version of RAVLT, TMT, attention task (television recall)	(1)50 g glucose, (2)50 g carbohydrate from potato, (3)50 g carbohydrate from pearled barley, (4)23.7 mg saccharin	10–12 h	No effect of treatment on cognitive performance. Significant predictors of declarative memory were glycaemic regulation, BMI, and beta-cell function.
Kaplan et al., 2001 [33]	N = 22 older adults (11 male) aged 61–79 (M = 71.2, SD = 1.3)	Tailored version of RAVLT, paragraph recall, TMT, attention task (television recall)	(1)50 g glucose, (2)50.5 g whey isolate (protein) + 23.7 mg saccharin, (3)41.4 g micro-lipid + 23.7 mg saccharin, (4)23.7 mg saccharin	10–12 h	Protein, glucose, and fat (ps < 0.001) improved delayed recall at 15 min compared to placebo. Protein (p = 0.04), glucose (p = 0.02), and fat (p = 0.008) improved immediate recall at 15 min compared to placebo. No effect of treatment on recall or TMT at 60 min. Fat ingestion improved attention at 60 min.
Kennedy and Scholey, 2000 [86]	N = 20 young adults (6 male) aged 19–30 (M = 20.4)	Serial threes and sevens, word retrieval	(1)25 g glucose, (2)30 mg saccharin	9 h	Improved performance in serial sevens after glucose ingestion (p < 0.01). Performance in serial threes and sevens positively associated with fall in BGL during task (ps < 0.05). No significant effect of glucose on word retrieval.
Maben and Smith, 1996 [49]	N = 48 young adults (24 male) aged 18–32	Word list, Baddeley Logical Reasoning Task, Semantic memory task (not described)	(1)No sugar, (2)Sugar, (3)Aspartame, (4)No sugar + caffeine, (5)Sugar + caffeine, (6)Aspartame + caffeine	9 h	Sugar and aspartame conditions performed more accurately on logical reasoning than control (p < 0.05) but more slowly (p < 0.001). No effect of sugar or aspartame on free recall, semantic memory, or recognition memory.
Macpherson et al., 2015 [87]	N = 48 (24 young adults aged 18–23 (M = 20.6, SD = 1.4) and 24 older adults aged 65–85 (M = 72.5, SD = 5.1))	Auditory word recognition, target tracking task	(1)25 g glucose (2)30 mg saccharin	12 h	Tracking precision improved in older adults after glucose ingestion (p = 0.05) after controlling for BMI, IQ, and glucose regulation. No effect of glucose in younger adults.
Mantantzis et al., 2018 [88]	N = 112 (54 undergraduate students aged 18–27 and 58 older adults aged 65–82)	Choice reaction time task	(1)25 g glucose (2)Aspartame	2 h	Glucose improved speed (p = 0.001) and accuracy (p = 0.007) in the older adult group only.
Martin and Benton, 1999 [89]	N = 80 female undergraduates (M age = 22.6)	Consonant trigrams	(1)50 g glucose aft fast, (2)50 g glucose after breakfast, (3)Aspartame + saccharin after fast, (4)Aspartame + saccharin after breakfast	Overnight fast vs. no fast	Performance improved over time for fasting plus glucose (p < 0.001), breakfast plus glucose (p < 0.03), and breakfast without glucose (p < 0.001). Falling BGL during the task was associated with better recall (p < 0.001).
Meikle et al., 2004 [53]	N = 25 adults (17 female) aged 18–52 (M = 28.4, SD = 9.3). Younger group (N = 14, M age = 21.8, SD = 3.3) and middle-aged group (N = 11, M age = 38.4, SD = 6.7)	Choice reaction time task, TMT, letter cancelation test, word retrieval, word list	(1)25 g glucose, (2)50 g glucose, (3)Placebo (4)Good vs. bad glucose regulators	9 h	Older adults saw improvement in reaction time for high memory load tasks after 25 g (p < 0.05) or 50 g (p < 0.01) of glucose. All participants had improved delayed free recall after 25 g (p < 0.05) and 50 g (p < 0.01) of glucose.
Meikle et al., 2005 [54]	T1: 37 young adults (29 female aged 17–48 (M = 28.3) T2: N = 24 young adults (20 female) aged 18–20 (M = 18.9)	Word list	T1: (1)25 g glucose prelearning, (2)25 g glucose postlearning, (3)Placebo T2: (1)25 g glucose, (2)Placebo	9 h	T1: No main effect of treatment post hoc; for higher difficulty task, placebo forgot more words than glucose prelearning (p < 0.01) and postlearning groups (p < 0.05) T2: Glucose performed better on high memory load tasks (p < 0.01) but not on high cognitive demand tasks.
Messier et al., 1998 [90]	N = 100 female undergraduate students aged 17–48 (M = 21.3, SD = 4.6)	Word list	(1)10 mg/kg glucose, (2)100 mg/kg glucose, (3)300 mg/kg glucose, (4)500 mg/kg glucose, (5)800 mg/kg glucose, (6)1000 mg/kg glucose, (7)52 mg saccharin, (8)Water	12 h	Increased primacy word recall after 10, 300, 500, 800, and 1000 mg/kg compared to one or both controls. Increased recency word performance after 500 mg/kg glucose. Impaired performance on recency word recall after 10 and 300 mg/kg glucose.
Miller et al., 2013 [91]	N = 36 adults (11 male; M age = 23.3, SD = 7.0)	Anagram problem solving	(1)25 g glucose, (2)25 g fructose, (3)Sucralose	3 h	Fructose (p = 0.01) and glucose (p < 0.01) solved more problems than placebo.
Mohanty and Flint, 2001 [92]	N = 70 undergraduate students (22 male; M age = 20.6, SD = 4.3)	Recall of object location task (pattern recognition)	(1)50 g glucose, (2)100 mg/kg glucose, (3)23.7 mg saccharin	8 h	In the emotional condition, more errors were made following glucose ingestion (no p values given). In the neutral condition, fewer errors were made following 100 mg/kg glucose compared to placebo. Response time was slower following 50 g glucose. More errors were made in spatial memory retention following glucose ingestion.
Owen et al., 2010 [55]	N = 90 undergraduate students (29 male) aged 18–30 (M = 21)	Word list, face recognition test	(1)25 g glucose, (2)60 g glucose, (3)Placebo	12 h	Improvement in implicit memory following 60 g glucose (p < 0.01). More false alarms after 25 g glucose compared to placebo or 60 g glucose (ps = 0.03).
Owen et al., 2012 [56]	N = 30 adults aged 18–25 (M = 20)	Word list, serial threes and sevens, Corsi block-tapping, STROOP, simple response time task	(1)2 h fast and 25 g glucose, (2)2 h fast and 60 g of glucose, (3)2 h fast and 0 g glucose, (4)12 h fast and 25 g glucose, (5)12 h fast and 60 g glucose, (6)12 h fast and 0 g glucose	2 h vs. 12 h	60 g glucose increased working memory (speed of recognition (p < 0.05) and serial threes (p < 0.01)) after fasting. Reaction time impaired with 25 g glucose after fasting.
Owen et al., 2013 [57]	N = 24 young adults aged 18–30 (M = 20)	Word list, serial threes and sevens, Corsi block-tapping	(1)25 g glucose, (2)60 g glucose, (3)Placebo	12 h	Improved working memory and declarative memory after 25 g and 60 g glucose (ps < 0.05). Improved spatial working memory and word recognition after 25 g (ps < 0.05) and 60 g (ps < 0.01) glucose. No effect of glucose on accuracy. Participants with poor glycaemic control performed better on recall after 25 g glucose (p < 0.05). Improved response time after 25 g (p < 0.05) and 60 g (p < 0.01) of glucose.
Parker and Benton, 1995 [93]	N = 100 females (M age = 20.15)	Dichotic listening task, word list, choice reaction time task, auditory word recognition	(1)75 g glucose, (2)Aspartame and acesulfame K	No	No effect of glucose on recognition Glucose drinkers recalled more when they nominated their right ear than left (p < 0.005), whereas placebo drinkers did not. Recall from attended (p < 0.013) or unattended (p < 0.034) right ear was better when BGL falling rather than rising.
Peters et al., 2020a [30]	N = 32 adults (16 younger adults aged 21–30 (8 female, M age = 25.8, SD = 3.2) and 16 older adults aged 55–78 (8 female, M age = 68.6, SD = 6.5))	Serial sevens, Virtual Morris Water Maze	(1)25 g glucose, (2)30 mg saccharin	12 h	Older adults performed worse than younger in placebo condition (p = 0.02) but not glucose condition. Older adults had poorer glucose regulation (p = 0.002) and a greater response to glucose (p = 0.006) than younger adults.
Riby et al., 2004 [94]	N = 20 older adults (M age = 68.75, SD = 6.0)	Verbal Paired Associates, digit symbol substitution, digit span	(1)25 g glucose, (2)38 mg saccharin	Unclear	Greater recall in glucose compared to placebo group (p < 0.05); immediate recall most sensitive to glucose (p < 0.01).
Riby et al., 2008 [95]	N = 33 middle-aged adults (19 females) aged 35–55)	Word list, national adult reading test, digit symbol substitution, letter cancellation, TMT, digit span, category fluency	(1)25 g glucose, (2)50 g glucose, (3)Saccharin	2 h	50 g glucose scored higher on word recall accuracy than 25 g or placebo (p < 0.001). Good glucose regulators performed better on trail making, except after 50 g glucose (p = 0.05). Consumption of “sugar, calories, sweets and drinks” were related to poor glucose control (p < 0.05).
Riby et al., 2011 [96]	N = 56 adults (25 male) aged 17—80 (M = 34.4, SD = 17.0)	SART	(1)25 g glucose, (2)Saccharin	3 h	Increased speed of response after glucose (p < 0.05). No effect of glucose on accuracy or sustained attention. Good glucose regulators had quicker responses compared to poor regulators (p < 0.05).
Scholey et al., 2001 [97]	N = 30 adults (11 male) aged 20–30 (M = 27.7)	Serial sevens, word retrieval, word list	(1)25 g glucose, (2)30 mg saccharin	9 h	Glucose ingestion led to more responses in serial sevens (p < 0.05). BGL fell more during serial sevens (high cognitive load task) regardless of treatment (p = 0.009). No effect of glucose on verbal fluency or memory.
Scholey et al., 2009 [98]	N = 120 adults (77 female; M age = 21.6, SD = 4.9)	Word recognition (auditory), tracking task	(1)25 g glucose, (2)30 mg saccharin	11 h	Improved tracking after glucose ingestion (p = 0.045). No effect of glucose on recognition accuracy or reaction time.
Scholey et al., 2014 [58]	N = 160 adults aged 18–55	Arithmetic task, STROOP, memory search task, target tracker	(1)25 g glucose, (2)60 g glucose, (3)40 mg caffeine + 60 g glucose, (4)Placebo	12 h	No difference between glucose groups and placebo. Improved scores due to caffeine + glucose.
Serra-Grabulosa et al., 2010 [59]	N = 40 students (20 male) aged 18–25 (M = 19.6, SD = 1.7)	Continuous Performance Test—Identical Pairs (CPT-IP)	(1)75 g glucose, (2)75 mg caffeine, (3)40 mg caffeine + 60 g glucose, (4)Placebo	8 h	No effect of treatment on performance.
Smith and Foster, 2008 [99]	N = 32 adolescents (12 male) aged 14–17 (mean = 15.6, SD = 0.9) N = 10 in glucose second test condition	Modified CVLT-II	(1)25 g glucose, (2)Aspartame	9.5–10.5 h	No effect of glucose on recall. Treatment x treatment order effect—improved performance for glucose ingestion only when glucose ingested in second session after placebo trial.
Smith et al., 2011b [100]	N = 58 adolescent males aged 14–17 (M = 15.5, SD = 1.0)	Modified CVLT-II	(1)25 g glucose, (2)Aspartame	9.5–11 h	More items recalled after glucose ingestion on 4th (p < 0.05) and 5th (p < 0.01) trial. Glucose only improved memory in those reporting higher trait anxiety (p < 0.05).
Spiers et al., 1998 [101]	N = 48 adults (24 male) aged 18–35	Word list, digit span, Corsi block test, TMT, Go-No-Go, Controlled Oral Word Association Test (COWAT), STROOP	(1)90 g/d sucrose, (2)15 mg/kg Aspartame, (3)45 mg/kg Aspartame, (4)300 mg cellulose (5)(3-month dietary intervention)	No	No effect of treatment on cognitive performance.
Stollery and Christian, 2013 [102]	M = 93 adults (35 male) aged 18–35 (M = 20.7)	Word list recall, spatial location recognition, category verification	(1)50 g glucose, (2)75 mg saccharin	Unclear	No effect of glucose on any outcome.
Stollery and Christian, 2015 [103]	N = 80 adults (26 male) aged 18–51 (M = 22.4)	PAL	T1: (1)50 g glucose pre-learning, (2)50 g glucose post-learning, (3)75 mg saccharin pre-learning, (4)75 mg saccharin post-learning T2 (retrieval—1 week): (1)50 g glucose, (2)75 mg saccharin	9.5 h	T1: No effect of glucose on performance. T2: Glucose ingestion at retrieval led to improved retention (p = 0.016) and lower omission errors (p = 0.008).
Stollery and Christian, 2016 [104]	N = 31 adults (9 male; glucose M age 22.5, SD = 1.5; placebo M age = 26.5, SD = 4.0)	Object-location binding task	(1)30 g glucose, (2)45 mg saccharin	9.5 h	Improved location memory (p = 0.029) and object-location binding memory (p = 0.006) after glucose ingestion. No effect of glucose on object memory, retrieval time, or errors. Higher BGL associated with better location memory (p = 0.027) and binding memory (p = 0.012).
Sünram-Lea et al., 2001 [105]	N = 60 adults aged 18–28 (M age = 21)	CVLT, Rey–Osterrieth complex figure drawing modified digit Span	(1)25 g glucose + 9 h fasting, (2)Aspartame + 9 h fasting, (3)25 g glucose + 2 h fasting after breakfast, (4)Aspartame + 2 h fasting after breakfast, (5)25 g glucose + 2 h fasting after lunch, (6)Aspartame + 2 h fasting after lunch	9 h or 2 h	Superior performance of glucose on immediate recall interference list (p < 0.01), no effect of fasting condition. Short-delay free recall improved after glucose (p < 0.001) and after breakfast compared to lunch and 9 h fasted (ps < 0.001). Short-delay cued recall, long-delay free recall, and long-delay recognition improved after glucose (ps < 0.001); no effect of fasting condition. Long-delay cued recall improved after glucose (p < 0.001), and breakfast outperformed lunch (p < 0.05). Rey–Osterrieth performance superior after glucose (p < 0.005), no effect of condition. No effect of drink or condition on digit span.
Sünram-Lea et al., 2002a [106]	N = 80 (18 male) adults aged 18–29 (M age = 20)	Modified CVLT, modified Rey–Osterrieth, complex figure drawing, modified serial sevens	(1)25 g glucose, (2)Aspartame	2 h	Superior performance of glucose on immediate recall interference list and long-delay recognition (p < 0.01). Aspartame improved long-delay cued recall in conditions with no interference (low cognitive load) (p < 0.05). Glucose facilitation effect in other short- and long-delay cued and free recall seen only in interference conditions (high cognitive load). Rey–Osterrieth performance superior after glucose (p < 0.05). Serial sevens performance superior after glucose (p < 0.005).
Sünram-Lea et al., 2002b [50]	N = 60 adults (26 male) aged 19–34 (M = 21)	Modified CVLT, serial sevens, ROCF (Delivered at baseline, 15 min, and 24 h after treatment)	(1)25 g glucose, (2)Aspartame (3)(On day one only)	2 h	Improved performance on delayed free recall after glucose ingestion (p < 0.001). Improved 24 h delayed free recall (p < 0.001) and recognition (p = 0.007) after glucose ingestion. After 30 min, glucose performed better on delayed reproduction of figure (p = 0.03). No effect of glucose on immediate free recall or serial sevens performance.
Sünram-Lea et al., 2008 [107]	N = 56 young adults aged 18–25 (M = 20)	Word list	(1)25 g glucose, (2)Aspartame	2 h	Increased recognition responses (recalling words associated with memories or experiences) following glucose ingestion (p = 0.04).
Sünram-Lea et al., 2011 [108]	N = 30 young adults (6 male) aged 18–25 (M = 20)	Serial threes and sevens, word list	(1)15 g glucose + 14 saccharin tablets, (2)25 g glucose +7 saccharin tablets, (3)50 g glucose +5 saccharin tablets, (4)60 g glucose + 3 saccharin tablets, (5)20 saccharin tablets	12 h	Improved spatial working memory (Corsi block task) after 25 g glucose ingestion (p < 0.02). Improved immediate free recall after 25 g glucose ingestion (p < 0.01). Improved recognition performance after 25 g glucose ingestion (p < 0.05). No effect of glucose on numeric working memory (serial threes and sevens) or delayed free recall. Good glycaemic control associated with improved performance after 60 g glucose. Poor glycaemic control associated with improved performance after 15 g glucose.
van der Zwaluw and et al., 2014 [61]	N = 43 older adults (16 male; M age = 77.7, SD = 5.6)	RAVLT, PAL, story recall, verbal fluency, digit span, STROOP, Test for Attentional Performance (TAP)	(1)50 g glucose, (2)100 g sucrose, (3)Placebo	10–12 h	Improved attention, working memory, and information processing after sucrose compared to placebo (p = 0.04). Improved tap flexibility.
Walk et al., 2017 [60]	N = 113 children aged 9–10	Erikson flanker task	(1)Sucrose, (2)Maltodextrin, (3)Carbohydrate blend (68% isomaltulose, 9% maltodextrin, 13% Fibersol-2), (4)Sucralose	10 h	No effect of treatment on cognitive performance. When glycaemic regulation was adjusted for, only Maltodextrin had improved reaction time (p = 0.044).
Winder and Borrill, 1998 [109]	104 adults (52 male) aged 18–55 (mean = 29.2, SD = 9.23)	Name–face association task, selective reminding task	(1)50 g glucose with oxygen, (2)50 g glucose with air, (3)4 g aspartame with oxygen, (4)4 g aspartame with air	No	No effect of glucose on performance.

M = mean; RAVLT = Rey Auditory Verbal Learning Memory Test; WCST = Wisconsin Card Sorting Test; WAIS = Wechsler Adult Intelligence Scale; TMT = trail making tests; RIPT = rapid information processing task; SART = sustained attention to response task; CVLT = California Verbal Learning Test; CDR = Cognitive Drug Research; ROCF = Rey–Osterrieth Complex Figure; PAL = paired-associate learning; BGL = blood glucose level.