Study	Reason for exclusion
Abbatecola 2009	Although this was a randomised controlled trial two pharmacological agents, repaglinide and glibenclamide, were the interventions used.
ACTRN12610000624088 2010	The ages of the participants ranged from 45 to 60 years. There is no specific data on participants aged 55 or over for meeting the criteria for inclusion in the systematic review.
Amagase 2009	Although this was a randomised controlled trial, the end‐points were antioxidant biomarkers with no cognitive measures.
Ban 1991	Although this was a randomised controlled trial, the participants had dementia.
Benton 2003	Although this was a randomised controlled trial, the participants were young adults and there was no placebo control.
Benton 2004	Although this was a randomised controlled trial, the participants were young adults.
Bergenstal 2008	Although this was a randomised controlled trial two pharmacological agents, glulisine and glargine, were the interventions used. There was no outcome measure of cognition.
Best 2008	Although this was a randomised controlled trial, the mean age of the study sample (N=45) was below 55 (mean age 52.1 ± 5.86 years).
Best 2010	Although this was a randomised controlled trial, the mean age of the study sample (N=109) was below 55. Mean ages for the placebo and treatment groups were 52.44 ± 4.16 and 53.36 ± 4.58 years respectively.
Block 2008	Although this was a randomised controlled trial, behaviour changes pertaining to life‐style were the outcome measures and not cognition.
Brandt 2010	The participants were young adults.
Brinkworth 2009	Although this was a randomised controlled trial, the mean age of the study sample (N=106) was below 55 (mean age 50.0 0.8 years).
Cheatham 2009	Although this was a randomised controlled trial, the participants were young adults.
Conti 1989	There was no randomisation and the particpants had dementia. There was also no placebo control.
Corsica 2002	Although this was a randomised controlled trial, the participants were young females of age between 20‐45 years.
Craft 1994	There was no randomised allocation sequence.
Cukierman‐Yaffe 2009	Although this was a randomised controlled trial, only the relationship between glycaemic control and cognition was analysed.
DeFrance 1997	There was no randomisation and the participants were young adults. The intervention was amino acids.
Finnigan 1998	The participants were young adults. There is inadequate information of randomised allocation of participants.
Fischer 2001	There was no randomisation and the participants were young adults.
Fischer 2002	There was no randomisation and the participants were young adults.
Ford 2002	Although this was a randomised controlled trial, the participants were young adults.
Gariballa 2006	Although this was a randomised controlled trial and of appropriate age, the participants were hospitalised and acutely ill.
Garriballa 2007	Although this was a randomised controlled trial and of appropriate age, the participants were hospitalised and acutely ill.
Halyburton 2007	Although this was a randomised controlled trial, the mean age of the study sample was below 55 years.
Henderson 2006	Although this was a randomised controlled trial, the was no placebo or non‐intervention control.
Kaplan 2000	There was no randomisation.
Kaplan 2001	There was no randomisation.
Kennedy 2004	Although this was a randomised controlled trial, the participants were young adults.
Krikorian 2012	The study assessed the potential cognitive benefit of dietary ketosis in older adults with mild memory decline.
Lee 2001	This was not a randomised controlled trial, with no control or non‐intervention group.
Levin 2009	Although this was a randomised controlled trial, the intervention was choline alphoscerate (cereton), a membrane phospholipid.
Lloyd 1994	Although this was a randomised controlled trial, the participants were young adults.
Malacco 1992	The intervention was dihydroergocristine.
Maridakis 2009a	Although this was a randomised controlled trial, the participants were young adults.
Maridakis 2009b	Although this was a randomised controlled trial, the participants were young adults.
Markus 1999	Although this was a randomised controlled trial, the participants were young adults and there was no placebo or non‐interventional control.
Markus 2002	Although this was a randomised controlled trial, the participants were young adults. In addition, the intervention was alpha‐lactalbumin, instead of carbohydrates.
Markus 2006	Although this was a randomised controlled trial, the intervention was dietary tryptophan, instead of carbohydrates.
Markus 2007	Although this was a randomised controlled trial, the participants were young adults.
Markus 2008	Although this was a randomised controlled trial, the participants were young adults. In addition, the interventions were hydrolyzed protein and alpha‐lactalbumin whey protein, instead of carbohydrates.
Meikle 2004	Although this was a randomised controlled trial, the participants were young adults.
Messier 2010	There was no randomisation.
Mischoulon 2010	Although this was a randomised controlled trial, the participants had seasonal affective disorder. There were no exclusion criteria for mild cognitive impairment and dementia as well as no cognitive outcome measures.
Morgan 2009	Although this was a randomised controlled trial, the participants were young adults.
Nabb 2006	Although this was a randomised controlled trial, the participants were young adults and there was no placebo or non‐interventional control.
NCT00980408	Although this is a randomised ongoing controlled trial, the participants are young adults.
Nilsson 2009	There was inadequate information on randomised allocation of participants in the counterbalanced design.
Pradignac 1995	This was not a randomised controlled trial, with no control or non‐intervention group.
Reger 2004	Although this was a randomised controlled trial, the intervention was a medium chain triglyceride.
Riby 2004	Counterbalanced design but no evidence of randomisation.
Riby 2006	Counterbalanced design but no evidence of randomisation.
Riby 2008	There was inadequate information on randomised allocation of participants in the counterbalanced design. The participants were younger than specified age.
Riby 2009	Counterbalanced design but no evidence of randomisation.
Rohleder 2009	Although this was a randomised controlled trial, the participants were young adults. The intervention was oral cortisol and not carbohydrates.
Salinsky 2005	Although this was a randomised controlled trial, the participants were young adults.
Sayegh 1995	There was no randomisation and the participants were young adults.
Scholey 2006	The participants were young adults.
Scholey 2009	Although this was a randomised controlled trial, the participants were young adults.
Smit 2004	There was no randomisation and the participants were young adults.
Smith 2009	There was randomised allocation to groups but the participants were young adults.
Vamosi 1976	There was no randomisation and no control or non‐intervention group.
Verger 1998	There was no randomisation and the intervention consisted of protein.
Wang 2004	Although this was a randomised controlled trial, the participants were young adults.
Wells 1998	Although this was a randomised controlled trial, the participants were young adults. The outcome measures were mood, energy expenditure, and heart rate.
Winder 1998	Although this was a randomised controlled trial, the participants were 55 years or less.
Wing 1995	Although this was a randomised controlled trial, the participants were young adults.
Young 2004	Although this was a randomised controlled trial, the participants were from an institution and had probable Alzheimer's dementia.